Natural Buildings
Our passion is to design buildings that are built out of materials that are the most sustainable, the least processed (non-manufactured = lowest embodied energy) and/or the most locally available.
We have experience designing ALL NATURAL buildings as well as being part of the team as the Project Architect of the Flemming College Sustainable Design projects for 2007 & 2008. The Fleming College's Sustainable Building Design and Construction course (based in Haliburton, Ontario) trains students to conceive and construct natural buildings using materials and methods with the least possible environmental impact. They develop strategies to design and build beautiful, healthy, and ecologically sound homes and public buildings. The course was created & led by Natural Building Expert, teacher, builder & author of 3 books on Strawbale construction, Chris Magwood. Ingrid Cryns, Project Architect, facilitated the working drawings, building permit & construction review process.
Natural Buildings employs many sustainable building methods, and makes use of non-toxic, healthy, low-embodied energy materials like hemp straw bales, milk paints and soy stains, and local earthen plasters.
- RD Lawrence Museum, Minden, Ontario - 2007
- Madoc Performing Arts Centre, Madoc, Ontario - 2008
- Earth Organic Farms, Cannington, Ontario 2008 – 2010
- Strawbale House, Erin, Ontario – starting Construction 2009
RD Lawrence Museum
Minden, Ontario
Launch Photo Gallery
To learn more about the Sustainable Building Design & Construction course see: www.sustainablebuilding2007.ca
To learn more about R.D. Lawrence see: www.crywild.com
Features
R.D. Lawrence Place was designed to use the most sustainable methods and materials to create a healthy, beautiful, functional, and environmentally-responsible building. Some of its sustainable features include:
- Passive solar design with south facing windows & concrete thermal mass floor
- Hemp-straw bale and slipstraw construction with earthen and lime plasters
- Cordwood interior walls with recycled materials
- Locally-milled and reclaimed windfall lumber
- Composting toilets
- Roof truss system with galvanized metal sheathing
- Soy based floor stain
- Solar hot water system
- Radiant floor heating
- Renewable electricity generation and demonstration
- Milk paint finished board and batten sheathing
- Non-toxic finishes and interior surfaces
- Mosaic tile washroom backsplash feature & baseboard
- Indoor constructed wetland for waste water treatment
Extensive use of local and recycled materials to keep the overall embodied energy as low as possible
Madoc Performing Arts Centre (MPAC) – 2008, Madoc, Ontario
The following description of the Madoc Performing Arts Centre is from www.sustainablebuilding2008.ca For more photo’s or to learn more about the Sustainable Building Design & Construction course, click on the above link.
Features
WALLS
The wall systems of the MPAC building are one of its most unique features.
The building is based on upon eight load-bearing columns made of large, round, hemp-straw bales. These 4x4 foot round bales are very tightly compacted when they are made, and stacked three high they make for very stable and strong columns. The columns were tested at Queens University for their structural strength.
The straight walls sections between the round bales are infilled with regular, rectangular hemp-straw bales. Both the round and square bales come from Moorcroft Hemp Farms (www.hemphomes.ca ), located just a few kilometers north of the building site.
All the bale wall sections are covered with a slip coat of clay. The round bales had a slip coat sprayed onto the surface, while the square bales had their two exposed faces dipped into a clay slip prior to installation. All the bale walls are then plastered with a clay/sand/straw plaster inside and out. All the clay for the plasters was found on-site, while digging the trenches for the geothermal heating system.
Clay plastered straw bale walls are one of the most environmentally friendly building systems available. The combination of locally-grown, minimally-processed straw and locally harvested clay means that the embodied energy in the wall system is only a tiny fraction of any other wall system. Combined with excellent thermal performance over the lifetime of the building, this system saves energy in every possible way, and is comparable in time and cost to any conventional building system.
For information on straw bale building try The Last Straw Journal at www.thelaststraw.org, and in Ontario, visit the Ontario Straw Bale Building Coalition website, www.osbbc.ca.
The three "wings" of the MPAC building are all based on conventional framing practices. Double 2x4 walls were used, which allowed the minimal amount of wood (which is all locally harvested and milled) to create walls of adequate thickness for good thermal performance. By spacing the two frame walls apart from each other, the thermal bridging effect is minimized which is the key weakness in most frame wall systems.
INSULATION
Three different insulation types were used for the three wings;
One wing is infilled with hempcrete, which is a site mixed combination of ground hemp, water and hydrated lime. This materials creates a light weight, rigid, insulative fill in the wall. We used slip forms on the frame walls to pack in the hempcrete. This is a similar mix and process to the one we used for the foundation grade beams.
The wall in the second wing is infilled with light clay/straw. For this material, we blended chopped hemp straw with a small amount of clay slip (a runny mixture of clay and water). This material is then packed into slip forms, resulting in an insulation with very similar properties to the hempcrete.
The third wing wall is insulated with cotton batt insulation. These batts are similar to fiberglass or Roxul batts, but are made from non-toxic, recycled denim fabric. They are installed in the same way as other batts, and have comparable R-values and fire ratings.
FOUNDATION
The foundation is made using compacted stone in an excavated trench to provide bearing capacity for the walls above. Crushed limestone called "3 inch minus" (any aggregate that would fall through a 3 inch screen) is compacted with a mechanical plate compactor, and is done after adding a depth of 12 inches of stone at a time. The sides of the trench are lined with a recycled carpeting that will keep the soil from migrating into the stone. The bottom of the trench has a drainage tile running in it, sloped on an angle to carry water away from the building.
This type of foundation is strong (the same type of compacted stone foundations support roads, railway tracks and other high-load situations), is self-draining, and is not prone to failure due to cracking like solid (concrete) foundations. The main reasons for choosing a rubble trench foundation are:
- Low embodied energy (local crushed stone has been minimally processed and transported)
- Low cost (no formwork, very little labour)
- Good performance (no concerns about leaks, cracks or other failures)
- High strength (compaction figures well established)
There are two different styles of grade beam foundations.
The earthbag grade beam that supports the main octagonal space is composed of woven polypropylene continuous tube sack material filled with a site soil mixture of gravel, sand, silt and clay and then compacted firmly. Barbed wire is run between each course of earthbag to prevent slippage. Two parallel runs of narrow bag with insulation (hempcrete) were placed between the runs. Earthbag foundations are very low cost, are strong enough for a large building like MPAC and are quite easy to build as they don't require formwork.
The hempcrete grade beams are being used for the first time ever on this building. Hempcrete is a mixture of chopped hemp, hydrated lime and a small amount of either portland cement or quick-set gysum. A reaction between the lime and the hemp results in a very lightweight material that still has reasonable compressive strength. The advantage of hempcrete over regular cement is that the hempcrete is both structural and insulative, so both ends are achieved in the same pour. It is also lower in embodied energy. The disadvantages are a longer set time (2-4 weeks) and lower strengths. However, where the high ultimate strength of concrete is not necessary, this option works well.
Some of its sustainable features include:
- Hemp-straw bale and slipstraw construction with earthen and lime plasters
- Locally-milled and reclaimed windfall lumber
- Hemp stray/clay mix, hempcrete, recycled denim, sheep’s wool and blown cellulose insulations
- Composting toilets
- Roof truss system with galvanized metal sheathing
- Solar hot water system
- Radiant floor heating
- Renewable electricity generation
- Locally milled, ragged edge, vertical board siding
- Non-toxic milk paint finishes and interior surfaces
- Extensive use of local and recycled materials to keep the overall embodied energy as low as possible
Here is a comprehensive list of SUPPLIERS for this project; http://www.sustainablebuilding2008.ca/index.php?
page=suppliers