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Residential Heating System Basics

Residential Heating System Basics

The ability to employ mechanical systems to automatically modulate the temperature (and often humidity levels) of our homes is a radical change from the previous centuries of human habitation. Our heating and cooling systems are often complex and high performance devices that give us fingertip control over indoor climate that would have been unthinkable less than a century ago. Until quite recently, the devices we used to achieve stable temperatures were functional but quite inefficient, using large quantities of fuel to meet our thermostat settings. A lot of development has gone into increasing efficiency, and in many cases this has come with increased complexity and cost. The following residential heating systems basics will help you understand your options.

Though most heating devices are intricate systems, it is quite easy to understand the basic technology behind each of them. It is worthwhile as a homeowner to understand these systems, and not leave it to company reps or installers to provide selling points.

It is easiest to think of heating and cooling systems as falling into categories of means of heat production and means of heat delivery. From this understanding, it is possible to narrow down the pool of options to those that suit the needs of a project.

Means of Heat Production

Despite all the competing products in the heating and cooling market, there are just four kinds of heat production. Details for each system are provided individually later in the chapter.

1) Solar Heat

In effect, all sources of heat are based on solar energy, as the fuels used in every heating system are the result of captured and stored solar energy. However, this classification of heating systems is based on direct harvesting of solar energy in real time. Heat from the sun can be collected (and sometimes concentrated) in, on or near the building and distributed for use throughout the building.

There are three basic types of solar heat, which may be used in any combination.

Passive Solar – A building may be designed with sufficient glazing on the sunny side of the building to allow for a measurable increase of indoor temperature when the sun is shining.

Active Solar Air – Collector units are used to gather and concentrate the sun’s heat in a flow of air that is supplied to a heat exchanger or directly to the building.

Active Solar Water – Collector units are used to gather and concentrate the sun’s heat in a flow of liquid that is supplied to a heat exchanger or directly to the building.

This category of heating devices does not include photovoltaic cells, which use solar energy to generate electrical current, and not directly to produce heat. Heat created by solar electric current is considered in the category of electric resistance heating.

Solar energy systems may appear to have low efficiency rates, with figures ranging from 10-70%, depending on ambient temperatures and type of collector, among other factors. These figures represent the percentage of available potential energy from the sun: approximately 1000 Watts per meter squared (W/m2) for a surface perpendicular to the sun’s rays at sea level on a clear day. A reduced figure of 800 W/m2 is often used in generating comparative figures for solar devices. While it is beneficial to increase efficiency rates to produce more heat from less collector area, the efficiency rates aren’t directly comparable to those of combustion devices as no sunlight is actually “wasted” and no harmful byproducts are generated by the solar energy that is not absorbed by the collector.

Solar heating systems do not generate emissions, fuel extraction and transportation impacts or air pollution, with the exception of those systems that use non-solar energy to drive small pumps or fans.

2) Combustion Devices

This category of equipment is by far the most prevalent. Regardless of the type of system and fuel used, all combustion devices burn a fuel and extract heat from the flame. All these devices rely on a supply of oxygen to react with the fuel and create the flame, an exhaust to allow spent combustion gasses to exit the unit and the building and a heat exchanger that passes the heat from the flame to the delivery system that supplies heat to the home. There are two broad categories of combustion devices:

Gas/Liquid Fuel Combustion – These are the dominant players in the market, and include all the various forms of fossil fuel such as natural gas, propane and oil, as well as bio-fuels like biodiesel and vegetable oil.

Solid Fuel Combustion – This group includes wood burning devices, as well as those that use other forms of biomass such as compressed pellets.

Combustion devices have efficiencies that range from 50% for some wood burning devices to 98% for some new gas burning devices. This means that less than all of the heat potential of the fuel is captured and used to supply the building.

Exhaust gasses from combustion devices differ depending on the fuel used and the combustion efficiency and conditions, but all devices release CO2 and a host of other byproducts with environmental effects.

3) Heat Pumps

This category of equipment is widely used in the form of air conditioners, and has started to capture a larger portion of the heating market. These systems use the refrigerant cycle to transfer latent heat from a source and deliver it to a destination or heat sink. It can be difficult to understand exactly how a heat pump works, but it is worth figuring out the principle at work in order to decipher manufacturer claims. Heat pumps can seem like they magically make heat from no heat if the refrigerant cycle is unclear.

heat pump explained

Heat pump explained

Mechanical energy (usually in the form of an electric motor) is used to cycle a volatile refrigerant that is chemically designed to boil and condense in the expected operating temperature range of the heat pump. The refrigerant is in its liquid state when it absorbs latent heat from a source (air, ground or water for most residential purposes). This heat does not need to be in a temperature range that feels warm or hot to the touch, as the refrigerant’s chemical properties will ensure its boiling point is at or near to the source temperature. Once the refrigerant has passed through the heat collection exchanger, the electric compressor pressurizes the warmed refrigerant, which is at or close to its boiling point. The pressurization causes the refrigerant to become a hot vapour. This hot vapour passes through a heat exchanger where the heat generated from pressurization is dispersed. The refrigerant condenses as the heat is removed. Condensed refrigerant now passes through an expansion valve where the pressure is released and the refrigerant returns to its liquid state and returns again to the exchanger and repeats the cycle until a thermostat indicates the proper room temperature has been reached.

It is the process of boiling and condensing a refrigerant under different pressures that creates the heat exchange. Useful heat exists in this boiling/condensing cycle, regardless of the actual boiling point of the refrigerant. As long as heat collection side is above absolute zero, there will be heat to extract. Consider the home refrigerator: cold is not being generated in the freezer, rather heat is being extracted from the freezer and released via the heat coils on the back of the fridge.

The refrigerant cycle can happen in either direction, and some types of heat pumps are designed to work as both heating and air conditioning units by reversing the direction of flow of the refrigerant.

There are three broad categories of heat pumps for residential use:

Ground Source Heat Pumps (GSHP) – The source of heat is the stable temperature of the ground (below the frost line in cold climates). Base ground temperature is very reliable and steady, and the ground provides a large surface area and capacity for heat exchange. Most GSHPs are reversible and can provide heat and cooling.

Air Source Heat Pumps (ASHP) – The source of heat is the ambient air temperature outside the building. As this temperature can be quite variable, different refrigerants and/or pumps are used to continuously extract useful heat from changing air temperature. Most ASHPs are reversible and can provide heat and cooling.

Air Conditioners (AC) – The source of heat is the uncomfortably warm air that is affecting comfort. These units provide cooling only.

Efficiencies for heat pumps far exceed those of combustion devices. The amount of energy input to provide compression of the refrigerant is significantly lower than the amount of heat energy that is extracted from the process and this how manufacturers claim efficiencies ranging from 200-500%. The heat is not “free” as some claim, but for every one unit of electrical energy applied to the system, 2-4 units of heat are returned. The systems don’t work without the electric motors, but they are much more efficient than combustion devices.

While there is no combustion and therefore no exhaust gasses from heat pumps, environmental impacts will vary depending on the source of electricity used to power the system. The refrigerants used can also be powerful greenhouse gasses, though stricter regulations are resulting in less damaging formulations.

4) Electric Resistance Heat

Electrical current can be passed through a resistive conductor to produce heat. This type of heat production is known as resistive, Joule or ohmic heating. The heat produced is proportional to the square of the current multiplied by the electrical resistance of the wire or element. The amount of current supplied can be adjusted to vary the heat output. Heat energy may be supplied through convection and/or infrared radiation depending on the kind of heating element used.

Efficiency of electrical resistance heating is considered to be 100%, as all the potential energy in the current is converted to heat. However, many sources of electrical power are less than 100% efficient, so overall system performance must take into account the type of generation used to supply the electricity.

The type of generation will also determine the environmental impacts, which can range from high for coal-fired power plants (with delivered power efficiencies as low as 35%) to negligible for renewable energy streams like solar, wind and microhydro.

Means of Heat Delivery

Heat flow always moves from a warmer object to a colder one. Heat flow can occur in three ways:

Conduction – Heat energy is transferred from a warmer object to a colder one by direct contact.

Convection – Heat energy is transferred from a warmer object to the air surrounding the object and then to cooler objects in contact with the warmed air. Warmed air become less dense and rises, creating convection currents that affect objects in the path of the current.

Radiation – Heat energy is transferred from a warmer object to a cooler object by electromagnetic waves, caused by energy released by excited atoms.

Heat transfer

Heat transfer

These neat categorizations do not adequately describe heat delivery systems in buildings, as any heating system will warm a space in all three ways to varying degrees. Consider the element on an electric range: anything that touches the hot element will be heated by conduction. At the same time, air near the element will be warmed, become buoyant and warm objects near the range by convection and the heated element will radiate heat to nearby cooler objects, warming the surface of the range and nearby utensils that are not touching the element nor in the path of heated air.

Certain heating systems will rely on one of these methods of heat flow more than others, but cannot be categorized by a particular kind of heat flow.

Instead, it is more useful to consider heating systems in regard to the medium of delivery, of which there are two. Almost any kind of heat production can be twinned with any kind of delivery system.

1) Air Delivery

Passive Air Delivery – These systems rely only on natural convection currents to move heat from a source to the desired locations in the building. No fans or ducts are used to direct warmed air.

Active Air Delivery – These systems use some form of mechanical energy to force air movement in a desired direction. Ductwork is often used to deliver a concentrated stream of warmed air to a particular location.

Air can be an effective medium for delivering heat in some circumstances. It is not very dense, and it is therefore easy to change the temperature of a large volume of air quite quickly. The energy required to move air from one location to another is low, as it flows and changes direction easily and large volumes can be moved quickly. Natural convection loops of rising warmed air and falling cool air can be exploited to good effect to contribute some or all of the required flow.

Occupants in buildings will feel heated air against their skin and have an immediate awareness of warmth and perceived comfort.

These advantages of air as a heating medium are also the disadvantages. The low density of air means that it loses its heat very quickly to more dense objects; raising the temperature of objects in a building via air flow can take a long time, and often objects and the surfaces of the building remain significantly cooler than the ambient air temperature. This can lead to discomfort as the warm occupants in the home will unwittingly be trying to heat the building’s surfaces radiantly, one of the reasons it’s possible to feel a “chill” even in a warm building.

The convection loops associated with air delivery ensure that the warmest area of the building is at the ceiling and the coolest is at the floor. Since occupants reside on the lower side of this balance, some heat is “wasted” by being concentrated outside the contact zone for occupants. Convection loops can also cause cool air to move against occupants in some areas of the building, causing the feeling of chilly drafts even in an air tight building.

In forced air systems with ductwork and fans, the layout must be done carefully if it is going to be efficient. Limiting the number of bends and restrictions increases flow, and proper positioning of outlets can reduce unwanted convection loops and create a relatively even distribution of heat.

Air heating systems will move a significant amount of dust and allergens as it flows. In forced air systems, inline filtration is highly recommended. For natural convection systems, an active filtration system is worth considering.

2) Hydronic Delivery

Using a fluid (typically water) to transfer heat from a source to a destination is a strategy with a long history. Water has a high capacity for absorbing and releasing heat in the range of temperatures used in buildings, and its high density means it can store a lot of heat.

Hydronic heating systems are often called “radiant” heating systems, especially when the heat is delivered to an entire floor area, but this is not an accurate description. Floor heat is conducted through feet, and a very even and useful form of convection accompanies the radiant transfer of heat.

Hydronic heat delivery can be achieved via a radiator that has a lot of surface area. Radiators can be the floor, walls and/or ceilings of the building, or purpose-built radiator systems. Water-to-air systems use a radiator inside forced air ductwork to create a hybrid system.

In all of these systems, produced heat is absorbed into the transfer fluid and moved through pipes through the action of a mechanical pump. The fluid is delivered through branch pipes to the point(s) of delivery where the heat is released, before being recirculated to the heat source again.

Hydronic heating systems will take a longer time to deliver perceptible heat, as the water requires more heat input to reach a perceptible temperature change. Once delivered to the radiator, the quantity of heat in the mass of the water and radiator creates much slower release times. The mass of air (and in some systems, even people) in the building will be lower than the heated mass, and all will rapidly be warmed to the radiator’s temperature without “draining” the radiator of its stored heat, resulting in longer but less frequent cycling of the heating system compared to air systems.

The design of hydronic systems needs to account for the surface area and distribution of the radiator(s), the length of piping and head, and the temperatures required to provide comfort based on the radiator layout. Systems can be quite simple, with a single pump and just a few radiator loops, or they can be complex with multiple pumps and valves responding to individual thermostats in each radiator zone.

Heating System Design: Heat Loss Calculation

Regardless of type of heat production and means of delivery, the design of an effective heating system starts with an accurate assessment of the expected heating needs for the building. This is achieve through the completion of a heat loss calculation. Many building codes now require such a calculation, and even if it is not a legal requirement it is recommended. Oversized or undersized heating systems are not efficient, and will cost a lot more than the calculation.

There are free, simple spreadsheets that can be used for heat loss calculations. These involve gathering dimensions for wall, floor, ceiling, window and door surface areas from the building plans and assigning each its expected heat loss rate (U-value or R-value). These figures are tallied and factored with the number of degree days and minimum anticipated temperature. The results include the hourly heat loss for the coldest expected day (expressed as BTU/hr) and total yearly heat loss (in millions of BTU).

More complex and comprehensive computer modeling programs will include more variables in the calculation, giving consideration to solar gain, thermal bridging in the building enclosure, anticipated air leakage rates and occupant behaviour among other factors. The more detailed the calculation, the more useful the resulting figures for sizing heating systems.

The hourly heat loss figure determines the maximum required output of the heating system, and the total yearly heat loss helps to anticipate energy requirements and costs. Figures from a good heat loss calculation also allow the design of the building to be tweaked for maximum efficiency at the design stage, as variables can be adjusted to determine ideal levels of insulation, window size and quality and air tightness.

With the parameters established by the results of the heat loss calculation, the particulars of the system can be designed to meet these needs in the most efficient and comfortable way.

Making Better Buildings book

This content is based on the book Making Better Buildings by Chris Magwood. 

Rammed Earth Construction Basics

Rammed earth construction basics

How does rammed earth construction rate? This introduction to rammed earth construction is from the book Making Better Buildings: A Comparative Guide to Sustainable Construction for Homeowners and Contractors, by Chris Magwood from the Endeavour Centre. The book gives unbiased information about all the different sustainable building material options.

Applications for rammed earth wall systems

  • Load-bearing wall systems
  • Interior walls
  • Built-in furniture, benches
  • Decorative elements

Basic materials

  • Earth
  • Stabilizer (cement or lime where required)
  • Insulation (where required)
  • Water-resistant finish (where required)

Control layers

Water control  — The finished rammed earth is typically the water control layer. It is possible to use vapor-permeable, water-resistant finishes on the rammed earth surface or to include water-resistant additives in the earth mix before ramming. Additional cladding over the rammed earth is feasible but rarely done.

Air and vapor control — Solid, continuous and dense, rammed earth is an effective air and vapor control layer.

Thermal control — A rammed earth wall requires an additional thermal control layer in hot or cold climates (see Thermal Mass vs. Insulation sidebar). This layer can be on the interior, exterior or center of the wall, and is typically a rigid insulation.

How rammed earth construction works

A lightly moistened earth mix with a relatively low clay content (10%–30% is common) is placed into forms in lifts, then tamped heavily to achieve a desired level of compaction. The soil mix varies by region and builder, but it is common to “stabilize” the mix with a small amount (3%–9%) of portland cement or other hydraulic binder.

The walls are built up in continuous lifts to full height. Often they are built in sections, so that formwork is not needed continuously around the building.

Window and door openings are usually created using a wooden “volume displacement box” or VDB. These VDBs hold the place of the window or door as tamping occurs around them. Once the wall is complete the VDB is removed, leaving a well-formed opening in the wall.

For large openings, lintels of wood, concrete or steel can be used above the opening; these are often buried in the rammed earth so they cannot be seen in the finished wall.

Electrical wiring and switch boxes (or conduits to receive them) are placed in the formwork before adding earth and tamping, and are formed right into the wall. Surface mounting after construction is also possible.

At the top of a rammed earth wall is a bond beam made of poured concrete, wood or steel. The beam is fastened to the top of the wall to provide a continuous attachment point for a roof. The method of fastening will depend on expected wind and seismic loads.

In hot or cold climates, insulation is part of a rammed earth wall system. The insulation can be a continuous wrap on the interior or exterior of the wall, but more commonly it is centered in the wall. Types of insulation used will vary with climate, availability, compressive strength and environmental factors.

Rammed earth walls are usually left exposed to provide the finished surface. A variety of sealants can be used on the raw earth to leave it visible but add protection from water. Plasters and others sidings are rarely used but are possible finishes.

Tips for successful rammed earth walls

  1. Formwork is the key to building with rammed earth, and the better the formwork the faster and more accurate the construction. Forms must be able to withstand the considerable forces of ramming the earth within and be able to be assembled and disassembled with a minimum of effort. Formwork that is reusable can help keep costs down. Check with experienced builders to see what formwork systems are being used successfully.
  2. Soils used for rammed earth must be very well mixed and not too wet. An even distribution of clay and any additional binders (cement, slag, lime, fly ash) is crucial to final wall strength. Rammed earth mixes do not benefit from the plasticity that water adds, and require plenty of mechanical mixing to achieve best results instead.
  3. Test potential soils before using. The makeup of the soil is critical to the performance of the wall. A lot of soil is required to make a rammed earth wall, and changes in its composition will mean that mixes may need to change too. Compact samples of the earth and use reliable sources to determine whether or not you will need stabilizers, and which ones are most appropriate for the soil type.
  4. Plan mechanical systems and wall openings carefully, as modifying rammed earth walls is time-consuming. If services are to be run within the walls, consider using conduit so that you can make changes and repairs without opening the wall.
  5. Avoid finishes that will reduce or eliminate the permeability of the rammed earth wall.
  6. If you are building your own home, consider buying the equipment you will need to dig, mix and tamp the earth. It can be much less costly to buy used equipment and re-sell it at the end of a project than to rent it for a long period of time.

        Pros and cons of rammed earth construction

Environmental impacts

Harvesting — Negligible to Moderate. Site soil can be harvested with negligible impacts. Amending materials like sand and cement have low to moderate impacts including habitat destruction and water contamination from quarrying.

Steel for reinforcing bar is extracted in a high-impact manner, with effects including habitat destruction and ground water contamination.

Manufacturing — Negligible to Moderate. Soil can be extracted and processed with negligible to low impacts.

Portland cement, if used, is fired at extremely high temperatures and has high impacts including fossil fuel use, air and water pollution and greenhouse gas emissions.

Steel reinforcement bar is made in a high-heat process that uses a lot of fossil fuel, and has impacts that include air and water pollution.

Transportation — Negligible to Moderate.

Sample building uses 79,410 – 105,666 kg of rammed earth:

74.6 – 99.3 MJ per km by 35 ton truck

Soil, cement and steel are heavy materials, and accrue significant impacts proportional to distance traveled.

Installation — Negligible to Moderate. The process of ramming the soil mixture can be done manually with negligible impact. More often, hydraulic machinery is used, with moderate impacts depending on power source.

Embodied carbon & energy of rammed earth construction:

rammed earth construction embodied carbon

Waste from rammed earth construction: Low

Biodegradable/Compostable — All leftover earth materials.

Recyclable — Metal reinforcement bar.

Landfill — Manufactured insulation offcuts, cement bags.

Energy efficiency of rammed earth: Low to High

A rammed earth wall has a lot of thermal mass and can easily be an airtight wall system, but it has no inherent insulation value (see Thermal Mass vs. Insulation sidebar). The overall energy efficiency of a rammed earth wall system will depend on the insulation strategy. Insulation can be placed on either the interior or exterior of the wall or a double wythe system can have insulation in the middle of the wall.

Insulation on either side of the wall will force a builder to create a finished surface over the insulation, which adds cost and complexity to the wall system and isolates all of the available thermal mass on one side or the other. Core insulation is more effective and leaves the rammed earth as the finish on both sides, but complicates the forming and tamping process and limits choice of insulation to materials that can resist the compressive forces of the tamping process.

Material costs of rammed earth construction: Negligible to Moderate

Components for good rammed earth may be sourced on site at negligible cost, but pre-mixed versions with Portland cement stabilizers may be moderately expensive. The addition of rigid foam insulation between two wythes of rammed earth will raise costs considerably.

Labor input of rammed earth construction: High to Very High

Rammed earth construction is labor intensive. The use of machinery can reduce the amount of labor involved in excavating, mixing and tamping earth, but even machine time can be extensive. Building, erecting and disassembling formwork takes a lot of time regardless of tamping method. However, when used as the finished wall surface, a rammed earth wall eliminates the need for steps often required to sheath and finish other walls.

Skill level required for rammed earth construction: Moderate to High

Mixing and tamping soil does not require prior experience, but the creation and use of formwork does, as does the operation of excavation and dirt-moving machinery. A first-time builder will want some training or experience prior to undertaking a major rammed earth project.

Sourcing/availability of rammed earth materials: Easy to Moderate

Soils suitable for rammed earth construction are widely available, as are the ingredients for amending soils that are not inherently suitable. The equipment used for excavating and tamping earth is common to other more conventional construction activities and should be easy to source.

Insulation materials will vary in availability depending on type and location.

Durability of rammed earth construction: Moderate to High

Rammed earth buildings have a long history in many parts of the world, with some examples lasting well over a thousand years. Erosion and/or spalling caused by excessive wetting are the main causes of failure. Creating adequate roof overhangs and site drainage can control this. Water repellents are sometimes mixed into the rammed earth or applied over exposed surfaces. These must not affect the strength of the mix or overly reduce permeability. Plasters and other forms of siding can also prevent moisture damage.

Rammed earth, like all soil-based construction types, can be repaired quite easily if damaged, by the addition of new soil mix.

Code compliance of rammed earth construction

Rammed earth construction is an accepted solution in some building codes, in regions where the technique has historical precedent. A good deal of testing and modeling of rammed earth walls has been done around the world, and the available data is usually sufficient to justify the use of rammed earth as a load-bearing wall for one- and two-story structures. A structural engineer may be needed to approve drawings to obtain a permit.

Indoor air quality of rammed earth construction: High

Uncontaminated earth is generally agreed to have no inherently dangerous elements and is consistent with the aims of high indoor air quality.

Soil contamination, from natural sources like radon or synthetic sources like petrochemicals, is possible, and it is wise to inspect and/or test soils carefully before using them to build a house.

Future development of rammed earth construction

Code development for rammed earth is moving forward in several countries, including the US and Australia. Widespread code acceptance is likely to encourage more rammed earth construction.

As the basics of rammed earth construction have remained the same for thousands of years, revolutionary developments in technique are unlikely. However, processes to reduce labor input for formwork and soil mixing and tamping are likely to be streamlined, making the system more affordable.

How does rammed earth construction rate?

rammed earth construction

 

Resources for rammed earth construction

Walker, Peter. Rammed Earth: Design and Construction Guidelines. Watford, UK: BRE hop, 2005. Print.

Easton, David. The Rammed Earth House. White River Junction, VT: Chelsea Green, 1996. Print.

Minke, Gernot. Earth Construction Handbook: The Building Material Earth in Modern Architecture. Southampton, UK: WIT, 2000. Print.

Rael, Ronald. Earth Architecture. New York: Princeton Architectural Press, 2009. Print.

Morton, Tom. Earth Masonry: Design and Construction Guidelines. Bracknell, UK: IHS BRE, 2008. Print.

Jaquin, Paul, and Charles Augarde. Earth Building: History, Science and Conservation. Bracknell, UK: IHS BRE, 2012. Print.

Keefe, Laurence. Earth Building: Methods and Materials, Repair and Conservation. London: Taylor & Francis, 2005. Print.

McHenry, Paul Graham. Adobe and Rammed Earth Buildings: Design and Construction. Tucson, AZ: University of Arizona, 1989. Print.

 

Essential Sustainable Home Design

FREE CHAPTER OF NEW BOOK! Essential Sustainable Home Design is the latest book by Endeavour’s Chris Magwood. Get a sneak peak at the book that’s based on our popular Design Your Own Sustainable Home workshop.

Many people dream of building a beautiful, environmentally friendly home. But until now there has been no systematic guide to help potential builders work through the complete process of imagining, planning, designing, and building their ideal, sustainable home.

Essential Sustainable Home Design walks potential homebuilders through the process using key concepts, principles, and a project matrix that will guide the house to successful completion.

The book includes:

  • How to clarify your ideas and create a practical pathway to achieving your dream
  • A criteria matrix to guide design, material, and systems decisions
  • Creating a strong, integrated design team and working with professionals and code officials to keep the project on track from start to finish
  • Key building science concepts that make for a high-performance, durable building
  • Primer on building logistics, material sourcing, and protocols to ensure that the initial vision for the project comes to fruition
  • One-page summaries and ratings of popular sustainable building materials and system options.

Ideal for owner-builders and sustainable building contractors working with clients aiming to design and build a sustainable home.

Download a PDF of the Building Permits chapter.

ESSENTIAL SUSTAINABLE HOME DESIGN IS AVAILABLE FOR PRE-ORDER NOW!

Peterborough Tool Library – New at Endeavour

Peterborough Tool Library – New at Endeavour

The Endeavour Centre is now more than just a sustainable building school! In June, we also opened the Peterborough Tool Library.

A tool library is like a typical library, but for tools instead of books. The Peterborough Tool Library allows community members to borrow from a large inventory of power and hand tools and take those tools home to use them. 

Endeavour director Jen Feigin had the idea to start the tool library, and she and her team of dedicated volunteers got the library up and running with an Indiegogo campaign that pre-sold memberships. They’ve been running the library for over 6 months now, with new members joining all the time. There is a dedicated group managing tool repairs and maintenance, and the inventory is constantly expanding.

For just $50 a year members can start borrowing tools… undertaking their own building and repair projects.

The Peterborough Tool Library is a community resource that will support independence, creativity, and sharing in our community!  

Jumbo bales and hempcrete – together!

Fifth Wind Farms wanted to create a building that could reach the energy efficiency requirements of the Passive House standard without resorting to the use of foam, mineral wool or other materials with a high carbon footprint. While straw bale buildings can have excellent energy performance, typical straw bale construction does not meet the Passive House standard without the addition of an extra layer of insulation (see our “Straw-Cell” project for a different take on this idea).

Jumbo straw bale duplex home

First jumbo bale in place (on a bed of Poraver insulation)

The building owner proposed the use of “jumbo bales,” which are produced from the same local straw and by the same low-carbon machinery, but are of dimensions that greatly increase their thermal performance. While typical straw bales are 14″ x 18″ x 32″, the jumbo bales used for this project measure 32″ x 32″ x 60″! At a nominal R-value of 2.0 per inch, that would give a jumbo bale wall a rating in the range of R-60, more than enough to help the building meet any energy efficiency rating.

However, the jumbo bales provide some issues when it comes to window and door openings… with a wall that thick, window sills and returns are extremely deep, creating not just aesthetic concerns but also concerns about air flow in the deeply recessed bays and the likelihood of condensation forming on the windows in cold weather.

Our solution was to form the window sections at a wall depth of 16″ using double stud framing and hempcrete as the infill insulation. This would keep us on track as far as low carbon footprint is concerned, and the hempcrete would be used to create the tapered window returns to meet the full depth of the bale walls. As a bonus, the hempcrete would completely fill any voids at the ends of the jumbo bales.

One issue with using jumbo bales: they weigh over 500 pounds each! We used a boom truck to install them in the building. With the bales in place and the top plate secured over the bales, we then mixed our hempcrete (you can find our recipe here) and tamped it into the framing and around the jumbo bales. The two materials are very complimentary, with the easily-formed hempcrete able to compensate for the uneven ends of the jumbo bales and creating smooth window returns.

 

The building is currently being prepared for plastering… more posts to follow soon!

SNC Class of 2016

Endeavour’s full time Sustainable New Construction program always attracts a diverse group of students, and 2016 is certainly no exception! People come from all across Canada and around the world to spend six months focused on the theory and the practice of building as sustainably as possible. Together we spend time in the classroom, on the job site, on field trips and with guest instructors.

We’d like to introduce you to the class by letting them introduce themselves to you:

 

Claire Clements

Claire Clements

Claire Clements – Claire is a wildlife film maker from Australia/New Zealand/Ireland.. who finds it hard to just pick one country to be from. She loves animals more than people, dogs more than cats and mountains more than beaches. Her current favorite food is Canadian wild rice even though its not rice and takes a ridiculous amount of time to cook. Claire’s hobbies include buying random pieces of land around the world, collecting earrings and any type of game or sport she is likely to win because she is unfortunately not gracious in defeat.

Her past times (for which she usually gets paid for – yay!) include filming incredible wildlife such as Asian otters and colugos (look them up!), narrowly avoiding death by natural disasters – 1 volcano, 2 earthquakes, and counting and dreaming up ideas for new films.

Claire believes strongly in changing the way we live – becoming more sustainable (climate change is real!) and not destroying any more of the planet or animal species. She plans to build a sustainable house in New Zealand, make a documentary about it and then see what happens next…

 

Alan Cundall

Alan Cundall

Alan Cundall

Hometown: Anywhere, Earth
Ambitions: Architect, Book Illustrator, Peace Activist
Favorite foods: Salmon, Chicken Roti, Cranberry Sauce.

Philosophy of life: Let your vision be world-embracing
Favorite pastimes: Running through hills and valleys, Watching “Manufactured Landscapes”, doodling in class since grade one.
Hobbies: Running, Biking, Swimming, Gardening, Drawing, Singing, Using hand drills
Favourite quote about sustainability: “Think globally, act locally”

Funny quirk: Has an awesome, seldom heard Scottish accent

2016 SNC AlastairAlastair Day – On reaching 30, Alastair felt like a change. He left the comfort of the boat yard in Gloucester docks and landed a job on a 100m super yacht. It soon became apparent that the title of carpenter didn’t involve any woodwork and consisted of hours of cleaning. Undeterred and two fun filled years later he decided to leave the yachting world and seek some adventure in the form of sailboat Benguela. Leaky and the bilges filled with diesel she headed out into the Atlantic. Three months later with a large, surprisingly, red beard Alastair and the crew sailed into Cape Town. After climbing Tabletop Mountain and visiting a Franschhoeks’ he quickly fell in love with another 1980s road bike and flew back to the British Isles. Greeted by a bale of hay and a herd of long horn cattle in need of feeding it was time for another challenge. A seed had been planted through prior periods of volunteering on straw bale / timber frame projects and a desire to become more knowledgeable in these areas arose. An interest in tiny homes, timber frame and semi subsistent living was explored whilst running a pop up yurt making business. On selling his last yurt he ventured to Canada to study with Endeavour. Thoroughly enjoying both the practical and theoretical side to the course Alastair looks forward to more sustainable building projects in the future.

2016 SNC AntoineAntoine DesRochers – Sup everyone, my name is Antoine DesRochers and I was born and raised in l’Acadie, a small town in Quebec, Canada. I came to the Endeavour Centre to develop an important project for me; building a village only from the material of the land where it will rise with my friends and family. Coming here was an important step for me that this quote from Terence Mckenna illustrates well:

“Nature loves courage. You make the commitment and nature will respond to that commitment by removing impossible obstacles. Dream the impossible dream and the world will not grind you under, it will lift you up. This is the trick. This is what all these teachers and philosophers who really counted, who really touched the alchemical gold, this is what they understood. This is the shamanic dance in the waterfall. This is how magic is done. By hurling yourself into the abyss and discovering it’s a feather bed.”

Peace!

Oh and I love my mom’s food.

 

2016 SNC ErinErin McLaine – Growing up on PEI Erin had lots of experience building houses out of twigs and snow banks, but these days you can find her trying to figure out how to make them last a little bit longer.

She’s a travel junkie who wouldn’t want to live without brownies or pizza, and fantasizes about owning a menagerie of primates and canines where she can use her creepy animal voice all day long.

She’ll never understand any of your pop culture references but will make any kind of art or food with you and will be pretty competitive if you challenge her to a sports duel.

She believes that without gorilla, there will be no hope for man

2016 SNC HughHugh Cunningham – Hi, my name is Hugh Cunningham. I am from the small town of Gananoque Ontario but Peterborough has been my home for the last seven years. I have spent a lot of my adult life as a canoe trip guide and outdoor educator. I love being in the outdoors in any way – especially canoeing, hiking, and cross country skiing. I have a deep appreciation of the natural world and I think that it is vital that we do what we can to keep it healthy.   I have been thinking of a career in building for the past couple of years but I wanted to work with sustainable materials and techniques. I first heard about the Endeavour Centre from a friend who had taken the Sustainable New Construction course in the past and it sounded like exactly what I had been searching for. Now that I am in the middle of a build with the Endeavour Centre I know that I will get the knowledge and skills that I need to become a sustainable builder.   If you want to capture my philosophy through a quote, I like this one: “What is the use of a house if you don’t have a decent planet to put it on?” – Henry David Thoreau

2016 SNC JubeJubokafloka , aka Jube-Jube, aka Julia Cicciarella – My name is Julia Cicciarella and i was born and raised in Newtonville ON, Canada. I am currently enrolled in the SNC ’16 class and i’m having an amazing experience. One of my favorite quotes about sustainability is: live simply so others can simply live. My philosophy of life is to keep learning, exploring and experiencing, my mother always told me be a moving target.

You can often see me folding pieces of paper, bending paper clips or tapping my foot when seated; i have a hard time staying still. I love to travel and meet new people anywhere i go. I also like to long board and play soccer with any free time i can find. I do not have a specific food i like, but rather focus on enjoying the company that gathers around to eat.

My ambitions are in a constant flux, changing almost every week, however two concrete ones I have had for some time now are to build my own house and to travel to every continent…at least once!

2016 SNC julesJulia Schubert – Hey! My name is Julia, or Jules, as there is more than one Julia in the program this year 😉 I am from a small town in Germany, but I have a big heart. Whenever we talk about sustainable building materials that are from Germany, I wave my little imaginary German flag (I get to wave it a lot).

The best thing in the world is eating mangoes and solving the world’s problems in a hammock, or maybe just reading.

I  jumped right into the program without any prior experience, and it has been great! Learning to use power tools and designing beautiful natural homes, and not just houses, working in a team and living in a community (20 people on a farm! Sometimes crazy but the pingpong tournaments and smores on the bonfire are amazing!)

“Logic will bring you from a to b. Imagination will take you everywhere”- Albert Einstein

Let’s save the world and build sustainably!

2016 SNC kristofKristof Wittstock
Hometown: Vienna, Austria
Ambitions: make an impact, live life as full as possible and let go of shit that holds me back.
Favorite foods: Everything Indian, Everything…almost.

Philosophy of life:  We do not see things as they are. We see them as we are.

Favorite pastimes: Yes

Hobbies: Hiking, Playing Guitar, Motorbikes, Axe throwing lately, Origami, Flower arrangements, Knitting, Dwarf throwing, Poetry, Line Dancing, Mud Wrestling, Public cuddling
Favourite quote about sustainability: ” Treat the earth well, it wasn’t given to you by your parents, it was loaned to you by your children.”

Funny quirk: Yes

2016 SNC Mike

Mike O’Reilly – My name is Michael O’Reilly. I was born and raised in Stratford Ontario and currently live in London, not far from there, with my wife and our two children. I am fortunate to have the opportunity to learn at Endeavour from Chris, Jen, and Shane for this year’s Sustainable New Construction (SNC) program.

The reason I am here is to learn about sustainable building and to obtain some practical experience with the intention of, one day, providing a place where older adults can live their lives with dignity—in a comfortable, affordable, and healthy environment.

While I am not participating in class and on the site, I thoroughly enjoy making human connections, seeking live music, learning how to drum, drawing, and dreaming!

As far as favourite foods are concerned, I have no enemies—I’ll try just about anything once, and a good ol’ Western sandwich is generally ace!

I have a few quirks—one of which I will share with you now. It has been brought to my attention by my family that I adopt an accent while speaking with telemarketers and bill collectors on the phone.

When it comes to a philosophy of life, I like to reflect on a piece titled Desiderata that is generally credited to Max Ehrmann (sp?); otherwise, I know, I don’t want to be the richest guy in the graveyard!

With regard to sustainability in every facet of my life, I like to consider the following quote from the great law of the Iroquois Nation:

“In our every deliberation, we must consider the impact of our decisions on the next seven generations.”

 

2016 SNC natalieNatalie Van Dreal

Hometown: Salem, Oregon

Ambitions: to be a more kind, helpful human; to be a part of a movement that helps us to earn more time on this beautiful planet; to help encourage, design and build thriving, regenerative communities — and most importantly, to make this accessible to and possible for everyone.

Favorite foods: pizza, popcorn, pickles, avocados, radishes and dark chocolate with salted caramel.

Philosophy of life: In regards to the human condition, I believe that humans need to unlearn a lot and instead focus on learning things like how to practice more compassion, humility, and simplicity. We need to reconnect with and understand the value of all the processes and organisms on which we rely to exist. I also believe that by realizing that we are not the pinnacle of evolution, we can find more purpose and meaning in our lives, and we can take bigger steps toward the kind of change that could benefit the earth and all its beings.

Favorite pastimes: playing with, petting and nurturing animals; spending time with my friends and family; hiking, swimming, singing, dancing, and laughing; cloud, star and moon gazing.

Hobbies: writing, drawing, painting, wood-burning, organizing, and decorating (transforming and enhancing spaces to be more beautiful, inviting and functional).

Favorite quote about sustainability: “These people, they all got white tiled toilets and take big dirty craps like bears in the mountains, but it’s all washed away to convenient supervised sewers and nobody thinks about crap anymore.. or realize that their origins are shit and civet and scum of the sea. They spend all day washing their hands with creamy soaps they secretly want to eat in the bathroom.” – Jack Kerouac, Dharma Bums

2016 SNC DanielDaniel Deza – Hello, my name is Daniel Deza. 33 years of age. I was born in Toronto, Ontario. And raised mostly in the countryside.

Well, my life has been through some major changes within the last few years, my personal wants and needs have transformed.

Entering the Endeavour course was one of those amazing choices I made to forever change the outcome of my future and to be prepared for my journey ahead.

When I caught wind of “ Ecological Communities “ ( Eco Communities ) during my personal time of transformation, I knew instantly that there was something very special about this movement in our current cycle of life….It called to me on many different levels. For a few years now it has been a dream of mine to grow old in an ecologically sustainable community.

I began my research, doing what I could to find workshops and courses to learn as much as I could about ecological/sustainable building, and who might be teaching these courses ?. My mind was racing to get my hands on the right source of information from the right teacher……..And one night, through a random internet search, my friend and I found the Endeavour Centre, and we quickly booked our tickets ( early bird special : ) ,Saturday and Sunday lecture, we couldn’t wait.

That was my first Endeavour workshop, “ build your own sustainable home “, and at the time had only briefly read about Chris and the course he designed. The Workshop blew us away…. along with the amount of usable, up-to-date, easy to understand  knowledge was by far the biggest asset for us, the ball didn’t just get rolling for us, it was canon balled. We had an idea where to start.

A few months had passed since my first workshop and was very excited to know about the six month Endeavour course!, there was still space left for a few students , I had a very big decision to make, and my faith was being exercised. I quit my full time job, enrolled in the Endeavour course, did a dance like Christopher Walken and said to myself…what the hell have I done !.?…

Thank you so much to our very in touch teachers at the Endeavour Centre: Chris, Jen, Shane, their beautiful friends, and their love for the earth. I want to thank my Amazing Mom ( The keeper of the keys ), my big brother, my sister, and my awesome friends for believing in my leap of faith. I love you all very much.

2016 SNC thumbsWe’ve enjoyed working with this crew a great deal… they bring energy, enthusiasm and a good dose of humour to every day on the work site and in the classroom!

Building a roof on the ground

At Endeavour, we tackle some fairly large building projects with our Sustainable New Construction program. This means completing a entire building from the ground up in just 5-6 months, from breaking ground to final finishes. Time is always at a premium, as is the safety of our students. For both these reasons, we often choose to build our roof structures on the ground and lift them into place with a crane.

 

Building on the ground allows us to have a team working on the roof right from the beginning of the project, rather than only starting the roof once the foundation and walls are completed. This kind of “multi-tasking” shortens the entire build cycle, as the mostly-completed roof is set in place as soon as the walls are ready to receive it. The building receives immediate weather protection and the project moves into the finishing phases very quickly.

The process of building the roof is also appreciably faster when it’s done close to the ground. Much less time is spent going up and down ladders and scaffolding, and the accuracy of the work is improved because workers feel comfortable and safe and can take their time to do jobs properly.

And of course, doing the whole project at ground level is a much safer way to learn to how to measure, mark, layout and install all the components of a roof. Much of the work can be done with feet planted firmly on the ground, and even when working at the peak the heights are limited.

For our jumbo straw bale duplex this year, we are again employing this technique, and this time the process includes full construction of the soffits, fascia and gable end siding.

 

The more complex the roof and roof details, the more sense it makes to build this way. None of our roof lifts have required more than 4-8 hours of crane time, which makes it a very affordable process (ranging between $750-1200), especially considering the time savings during construction.

And the day of the lift is exciting, a bit nervous, and a great sense of accomplishment as the building goes from open walls to full enclosed structure.

Building a roof on the ground

Relaxing after the excitement of lift day!

Sustainable Building Essentials from Endeavour and New Society Publishers

The Endeavour Centre is partnering with New Society Publishers to bring natural building enthusiasts a new series of books intended to cover the full spectrum of materials, systems and approaches to natural building.

Sustainable Building Essentials books

Called the Sustainable Building Essentials series, the books cover the full range of natural and green building techniques with a focus on sustainable materials and methods and code compliance. Firmly rooted in sound building science and drawing on decades of experience, these large-format, highly-illustrated manuals deliver comprehensive, practical guidance from leading experts using a well-organized step-by-step approach. Whether your interest is foundations, walls, insulation, mechanical systems or final finishes, these unique books present the essential information on each topic.

The first three titles in the series are now available for pre-order from the publisher, with a 20% discount:

Essential Hempcrete Construction

Essential Building Science

Essential Prefab Strawbale Construction

Upcoming titles in the series include:

  • Essential Straw/Clay Construction
  • Essential Green Home Design
  • Essential Rainwater Harvesting
  • Essential Natural Plasters
  • Essential Cordwood Construction
  • Essential Composting Toilet Systems
  • Essential Green Roofs
  • and many more…

We hope that this series helps continue Endeavour’s mission to bring affordable, accessible and accurate sustainable building information to a wide audience!

Light clay straw insulation

On April 10, a workshop at Endeavour led participants through the theory and practice of making wall insulation from light clay straw (also known as straw/clay, slipstraw, or EcoNestTM).

This is an insulating technique we’ve used numerous times on building projects at Endeavour, and we appreciate the extremely low carbon footprint, simplicity, lack of toxicity and simple installation process of this insulation.

Here is an introductory slide show about light straw clay insulation:

Clay slip versus dry mixing
During our workshop, we used the typical mixing approach for light clay straw insulation: mixing our clay into water until we had a thick, “melted milkshake” consistency. This slip is then poured onto the straw and mixed in until the slip evenly coats all of the straw, so that a handful of straw can be squeezed into a shape that reasonably retains its shape. Whether mixed by hand, in a mortar mixer or in a purpose made straw/clay tumbler, this is how we and other straw/clay builders typically prepare the insulation.

 

For this workshop, we also tried a mixing technique more similar to that we use for hempcrete. When mixing hempcrete, the hemp hurd and the binder are added together when dry, mixed until the powdery binder coats all the hemp, and then lightly misted with water to make the binder sticky. So we tried sprinkling dry powdered clay over the straw, stirring, and then adding water. This didn’t work so well, as the clay powdered sifted down through the straw and ended up at the bottom.

Dry mixing, version 2
For our next batch, we reversed the process and gave the straw a light misting of water and then sprinkled in the clay powder and stirred. This seemed to work very well, as we ended up with a clay coating on the straw that was much stickier than slip mix and allowed the clay/straw to be packed into the forms easily. This process used 25-50% less clay, and more importantly 25-50% less water, which should reduce drying time in the wall dramatically. Having placed both slip-mix and dry-mix side-by-side in the same wall system, there was no appreciable difference in quality in the finished appearance of the insulation, but the dry-mix showed about 25% moisture content on our moisture meter, and the slip mix was up at 36%. Given that slow drying time is the main hang-up for straw/clay insulation, we will use this technique in the future to reduce the wait for the insulation to dry!

NEXT STRAW/CLAY WORKSHOP: OCTOBER 30, 2016

Hempcrete developments

On April 9, a workshop at Endeavour brought participants together to explore hempcrete insulation materials.

The workshop looked at well-used options for these materials, but also explored some interesting new approaches.

Endeavour has continued to develop the use of homemade hydraulic lime binders as a means to eliminate carbon-heavy cement from our building materials and to create locally-sourced binders for cement replacement. At this point, our homemade hydraulic lime binder is well-tested and we feel it works as well as any of the imported (European) hempcrete binders, at a fraction of the cost and with locally-sourced ingredients.

Hempcrete mix
Our hempcrete binder is composed of 50% hydrated lime (most easily accessible to us is Graymont’s Ivory Finish Lime) and 50% Metapor metakaolin from Poraver (created as a by-product of the company’s expanded glass bead production).

We mix our hempcrete at a ratio of 1 part chopped hemp hurd by weight, with 1.5 parts of the binder by weight. After translating these weights to volume measurements, it was 4 buckets or hemp hurd going into the mixer with 1 bucket of binder (1/2 lime, 1/2 metakaolin).

 

hempcrete insulation

Weight ratios are converted to bucket measurements: 1/2 bucket of lime, 1/2 bucket of metakaolin, 4 buckets of hemp hurd

 

The hemp hurd goes into the mortar mixer first and then we sprinkle in the binder and allow it dry mix until the hurd is well coated with binder powder.

hempcrete insulation

A horizontal shaft mortar mixer is used to dry-mix the lime binder and the hemp before water is misted into the mix

Water is then misted (not sprayed) into the mixer until the mix is just moist enough that if we pack it like a snowball in our gloved hands it keeps its shape, but is still fairly fragile (ie, can be broken with a bit of a squeeze). It is important to not over-wet the hempcrete, as this will greatly extend the drying time once the hempcrete has been packed into a wall. If too much water is added, the mix can’t be recovered by adding more dry ingredients as the hemp hurd will quickly absorb excess water and there won’t be any free water for the new dry ingredients. So, add water carefully and gradually!

hempcrete insulation

When packed like a snowball, the hempcrete should just hang together

Hempcrete is placed into formwork on a frame wall, using light hand-pressure to compact the mix just enough to ensure that the binder will stick all the individual pieces of hemp together.

hempcrete construction

Hempcrete is placed into forms and lightly pressed into place. The forms are leap-frogged up the wall.

Our workshop crew was able to mix and place enough hempcrete to fill a 4-1/4 inch deep wall cavity that was 4-feet wide and 13-feet high in just under 3 hours! That’s over 6 cubic feet of material per hour!

Hempcrete recycling
We have long touted the no-waste benefits of hempcrete. We’ve speculated that even when the insulation is being removed from a building during renovations or demolition, that the hempcrete can be broken up and recycled into a new mix with new binder added. We put that theory to the test at the workshop, as we demolished one of our small sample walls and added the broken up hempcrete into our new mixes at a ratio of 3 parts new hemp to 1 part recycled hempcrete. The resulting mixes were impossible to distinguish from the all-new mixes, and confirmed that hempcrete can easily be re-used!

hempcrete insulation

Hempcrete that had already been mixed into a wall was broken up and added into a new mix… Fully recyclable!

Hempcrete book forthcoming
If you are interested in hempcrete insulation, Endeavour’s Chris Magwood has just finished a book called Essential Hempcrete Construction that will be available in June, 2016. It contains recipes, sourcing, costing, design and installation instructions and will be very valuable to anybody considering a hempcrete project.

hempcrete insulation

New book includes everything you need to know about building with hempcrete

Hemp-clay shows lots of promise!
Hempcrete insulation is almost always done using a lime-based binder. But at the Natural Building Colloquium in Kingston, New Mexico last October, we were doing a hempcrete demonstration right next to a straw/clay demonstration, and we took the opportunity to mix up a block of hemp hurds with a clay binder.

hemp clay construction

A sample block of hemp-clay showed the potential for this material combination

The success of that demo block led us to try this combination on a slightly larger scale, and we machine mixed the clay and the hemp to fill one tall wall cavity with this hybrid material. Using the same mixing methodology as typical hempcrete, we added the hemp hurd and dry bagged clay to the mixer and allowed it to dry mix, before misting with water. Interestingly, we were able to use half the amount of clay binder compared to lime binder (1/2 bucket of clay to 4 buckets of hemp hurd) and the resulting mix was stickier and easy to form and pack than with the lime, and with the addition of noticeably less water.

hemp clay construction

The hemp-clay mix has great binding power, and keeps its shape with very little pressure required

The key difference between the two binders is in their manner of setting. Hydraulic lime binders cure chemically, and consume water to change the chemical structure of the mix as it solidifies. Clay binders simply dry out and get hard. So the lime-based versions should be drier and harder sooner. However, the smaller quantity of water required in the clay-hemp mix may mean that drying times end up being similar… we’ll report back when we know.

hemp clay construction

A close-up of the hemp-clay mix formed into the wall. It keeps its shape within seconds of being placed into the forms

Clay binder with hempcrete offers some advantages over lime-based options, including a significantly lower carbon footprint and none of the caustic nature of lime that can cause skin burns when handling. The clay-based binder creates a mix that is much stickier during installation, which means less packing/tamping to get the material to cohere in the forms. Less water means that it was almost impossible to over-compact the mixture. We will definitely be exploring this option in a serious way!

hempcrete insulation

Having placed 18.5 cubic feet of hempcrete in a few hours, the crew stands in front of their work. The lighter coloured hempcrete is our homemade hydraulic binder, the darker mix is Batichanvre, a binder imported from France.

NEXT HEMPCRETE WORKSHOP: OCTOBER 29, 2016

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