Battle Lake Design Group

The Evolving Straw Bale House

BLDG — Fri, 08 Mar 2013 19:50:04 +0000

In previous postings we have discussed some of the design rationale and construction methodologies employed and advocated by our company. This is a more detailed analysis of technologies and materials used from foundation to roof.

Not too long ago the construction of a straw bale house involved the design of a custom foundation, sometimes complex and unorthodox framing, shimming trusses and rafters on an undulating box beam on a load bearing straw bale wall, and a host of other quirky construction methods not often encountered by professional builders and home owners. Part to our mandate has been to make straw bale construction simpler and more accessible.

Most of the homes we design are constructed on conventional basements; an eight inch concrete wall and strip footings with a standard I joist floor system. This is the same foundation most standard frame houses are built on. Even though the walls in a bale house are either fourteen or eighteen inches thick, our frame, a modified post and beam system, carries the majority of the structural loading of the building on the outer six inches of the wall, the same as a standard frame house. Interior walls are framed with standard 2×4 and 2×6 stud walls.

Windows and doors are secured in framed openings extending from floor to ceiling and the full depth of the wall, very similar to a frame house. Windows that ‘float’ or are suspended on a light 2×4 or 2×6 frame in a straw bale wall is not something we design or recommend.

Most of the roof systems for our homes are the same truss or stick framed systems you would find in a wood frame house, designed to fit on top of non -loadbearing straw bale walls and frame walls the same way they would in a conventional frame home.

Many of our designs would best be described as hybrids - employing straw bale, conventional frame construction and where appropriate, the use of steel and concrete. Interior walls and ceilings are finished with drywall, locally-milled wood or the many other materials available in the marketplace.

Working with our design team partners, Acius Structural Engineering, Habib John Gonzalez (Sustinable Works), local suppliers, and truss and joist manufactures, we have developed load bearing, structural frame system that uses standard materials and building technologies available at any building supply centre or lumber yard. Plumbing and wiring require only minor modifications (if any) to be adapted to a straw bale house.

Engineered truss roof systems, joist systems and standard basement foundation round out the integration and relative ease of construction we strive to achieve for straw bale home.

The evolving design of straw bale homes is not to make building technology adapt to straw bale, but having straw bale adapt to modern building technologies and products for ease of construction and higher guarantee of a success in home building for novice ‘owner-builders’ and experienced contractor alike.

For more information on straw bale technology or our design services, feel free to contact us.

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McKernan Duo Project under construction, March 2013

Non-Load Bearing vs. Load Bearing Straw Bale

BLDG — Sun, 24 Feb 2013 00:38:13 +0000

There are essentially two methods of constructing bale walls to support the roof structure and multi-storey walls (to a maximum of 3 storeys) in residential construction. They are:

load bearing wall assemblies
non-load bearing wall assemblies

Both systems have their advantages and challenges. We have chosen to focus our efforts on non-load bearing straw bale for a number of reasons. Moisture is the biggest enemy of straw bales during construction, and until a roof is constructed the bales are vulnerable to damage even when stuccoed. Load bearing bale walls must be compressed, leveled and stuccoed before second floor or roof assemblies are constructed.

Both non-load bearing and load bearing walls can be constructed on conventional basements with an engineered i-joist floor system, grade beams, reinforced slabs and rubble trench foundations. It is at this point the construction methodologies diverge.

Non-load bearing wall assemblies are a modified post and beam system, constructed from dimension lumber and plywood found at any local building supply center. These frame assemblies are the same width as the bales and become an integral and hidden part of the bales walls, buried behind the stucco along with the bales. They also form the ‘bucks’, the openings and structural members in which the windows and doors are inserted and secured. Once the box columns – the structural framing members that form the enclosures in which the bales will be stacked – are positioned, leveled and braced, a second floor or roof is constructed and the entire building is largely waterproof before any baling begins.

Tensioned stucco wire on the exterior provides a ‘form’ to bale to from the interior. The roof and its associated overhangs should be generous, not only ensuring protection for the baled walls but providing a dry and secure work area for bale storage during stacking, retieing, installing and tensioning stucco wire. It also provides a protected environment for stuccoing. The chances of bales getting soaked or newly applied cement-lime stucco being ruined by a summer thunderstorm or several days of rain is dramatically reduced or eliminated by completing the framing and roof first.

Battle Lake Design Group has been working on modified structural elements and techniques for straw bale construction since 2004 for our variable Western Canadian climates. We continue to refine and update the modified post and beam system in collaboration with Acius Structural Engineering Consulting to create additional labour and cost efficiencies for both builders and home owners building straw bale homes.

For more information on straw bale technology or our design services, feel free to contact us.

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Completed non-load bearing straw bale wall assembly showing roof framing and overhangs

Straw Bale Building for the DIY Crowd

BLDG — Fri, 15 Feb 2013 04:12:16 +0000

Straw bales as a choice in new housing is distinctly different from virtually all new products developed to enhance the efficiency of home construction from a structural, energy, environmental or cost efficiency perspective. New building products are often developed by large companies through research and development, then marketed, branded and patented. Straw bale, and its applications in house construction, is a grass roots technology, developed by small builders, home owners and ‘do-it-yourself-ers’ exploring a means of providing housing that is cost effective using local, renewable materials for energy-efficient, healthy homes.

Testing in Canada by CMHC and other housing certification agencies in the United States (with ASTM testing) have confirmed and quantified the many exceptional qualities of straw bale construction such as fire resistance, insulation properties, and sound attenuation. The technology is not propitiatory, brandable or patentable by any individual or company. It is a building material available to a broad range of potential home-owners.

Straw bale construction can engage the home owner and community. The raising of a straw bale wall in a properly constructed frame is a ‘low-tech’ procedure. With professional and experienced supervision, the average home owner can quickly master basic baling techniques such as stacking bales, re-tieing, installation and sewing of stucco wire, and the application of cement-lime stucco. This creates a personal connection with the construction of a home, both for the owner and often other family members, friends and the local community.

This ‘hands on’ experience is created by offering workshops led by one or two experienced individuals that can last from several days to a week or more that allow anyone with an interest in straw bale construction to participate and learn both basic and more advanced techniques.

Many of the homes we design are for owner-builders. The baling workshops are an integral part of the ‘house raising’ experience. We design homes that allow home owner involvement at a number of levels. Workshops are often led by Habib John Gonzalez of Sustainable Works, Inc., resident straw-bale workshop expert and a part of our integrated approach to straw bale building design.

We invite any potential homeowner thinking of having their home designed and possibly building their own home to contact us.

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Preliminary idea of one of our straw bale stock plans – single car garage with suite

Dispelling Myths Around Straw Bale Construction

BLDG — Wed, 06 Feb 2013 20:23:19 +0000

The two most common questions we encounter from individuals exploring straw bales as a building option are: “Do they pose a fire hazard?” and “Are they going to be a haven for mice and vermin?” This is a cursory overview of both issues which we will be dealing with in much more detail in future postings.

Straw bales are naturally fire resistant. The dry straw that makes up the bale is very combustible when loose, but compressed in the form of a bale, the straw does not trap enough air to allow easy or rapid combustion. Building-grade bales will burn and char on the surface but their density resists combustion. Straw bales are never left exposed on any sides in a properly designed straw bale building. There is a layer of cement-lime stucco on both sides of the walls along with a fire-stop assembly at the top of each wall section, between floors and roof systems.

A properly designed, constructed and stuccoed bale wall will give a fire rating that can far exceed a fire rated frame wall. Fire safety tests performed by the Research Council of Canada in 1984 withstood temperatures up to 1,850 F for two hours*. The Canadian result was confirmed by ASTM E-119-05a tests in New Mexico in 1993 and Texas in 2006 easily passed to obtain a two hour fire rated wall. The two hour fire rating is double the time required for residential structures and is the standard for commercial buildings in Canada and the U.S.A. The construction techniques and attention to detail on our projects is also a testament to the lasting fire retardant characteristics of a well-design, well-built straw bale building.

Straw bale walls are no more susceptible to an infestation of mice or other vermin than a standard exterior frame wall filled with fiberglass, foam or cellulose insulation. Making sure the walls are properly constructed and not providing holes or entry points are the best defense against the invasion of these creatures or other unwanted pests. Another common misconception is that straw bales provide a food source for mice. Straw is the dried stems from grain crops, and combined and baled properly they do not contain any food source or for rodents.

It is properly designed structural systems, attention to detail during baling, and application of cement-lime plasters that give straw bale buildings their superior fire ratings and make them impervious to rodents or other pests.

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Installing bales in a standard straw bale wall assembly between structural ‘box’ columns

*Magwood, Chris, Peter Mack and Tina Therrien. More Straw Bale Building: A Complete Guide to Designing and Building With Straw. First Edition. Gabriola Island: New Society Publishers, 2005. Page 32.

The ‘Pretty Good House’ a movement we can all build on

BLDG — Tue, 29 Jan 2013 19:29:26 +0000

A commentary in the recent edition of Fine Homebuilding Magazine’s ‘Energy-Smart Homes’ (Winter 2013) points out the need for more homes designed and built with energy-efficiency and other sustainable principles that are within the reach of the average home owner.

Residential designer and project manager Michael Maines explains the premise of the ‘Pretty Good House’, “It’s about finding the sweet spot between initial cost and long-term savings, paying attention to critical details while maintaining ease of construction, providing energy-efficiency without ignoring aesthetics, and allowing for comfort while maintaining reasonable size.”

Programs like Leadership in Energy and Environmental Design (LEED) and Passivhaus Institute are examples of building standards achieving the highest levels when it comes to sustainability. While they are admirable targets for many buildings, your average home owner may not have the desire or budget to attain or adhere to the strict rules required for those programs.

Some of the initial thoughts on what constitutes a ‘Pretty Good House’ where discussed at the September 2012 annual meeting of the Northeast Sustainable Energy Association in Portland, Oregon:

supports the local economy in material and labour use;
energy level monitoring after construction and on an on-going basis;
minimal or reasonable operating costs;
well insulated;
reasonable in size;
quality-built and durable construction;
possible to recycle in the future;
incorporates accessibility standards;
and must be well-designed and comfortable.

Battle Lake Design Group has demonstrated these sustainability goals in the homes we have designed. Mill Creek Flexhomes features energy-efficient straw bale construction while the design is modern and urban in context. Many of our homes are designed for ‘owner-builders’, young families or couples wanting to ‘age-in-place’, who act as their own general contractor and are directly involved in the construction of their home. This requires our designs to not only be energy efficient, but also executable and attainable on the average family’s budget.

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A straw bale studio designed and built by Battle Lake Design Group completed near Battle Lake in 2007

McKernan Duo

BLDG — Fri, 19 Oct 2012 22:34:44 +0000

Introducing our latest straw bale infill project in Edmonton! The McKernan Duo project was designed for local developer Kanoo Developments and is now under construction at 10973 76 Avenue.

Form and function marry environmental responsibility. It features open floor plans to encourage family, entertaining and accommodate more intimate spaces. Transitional spaces between indoors and outdoors, adequate natural light, views & privacy, sheltered entries and the defining of public and private spaces are our attention and focus.

Each 2 storey unit is 1367 sq. ft. featuring 2 bedrooms plus flex space, 2 1/2 bath. McKernan Duo semi-detached is designed to take full advantage of its southern exposure with substantial glazing that provides light in the winter, passive solar gain in the shoulder seasons and overhangs and sunshades to reduce heating during the summer. Generous windowing on both floors allows for natural light and natural ventilation, coupled with superior insulation eliminates the need for mechanical cooling. A second storey clerestory provides light and natural ventilation for hallway and main bath. A separated, private side entry allows for future self-contained basement development. Concrete floors on the main level provide thermal mass, excellent sound suppression between floors, and are fireproof and finished to provide a contemporary, easy care floor. Low and no VOC materials have been chosen to enhance the clean indoor air environment provided by the straw bale walls. Alberta aspen and clear pine feature prominently on the main floor ceilings as well as some of the trim an millwork throughout the house.

Now under construction – watch for updates and photos as the project progresses! For sales information, please contact Patti Proctor of Realty Executives Devonshire at 780.438.2500.

Developed by Kanoo Developments Ltd.
Project Management by Fixation Renovations Ltd.
Design and Construction Management by Battle Lake Design Group, Inc.

Straw bale home designed for future

BLDG — Sat, 07 Apr 2012 06:05:24 +0000

Edmonton Journal - April 7, 2012

Dave and Carol moved into the home in April 2010. Before they found it, they’d been looking at lofts downtown. Parking was an issue. But neither of them wanted a “cookie-cutter” home. They wanted something unique. And they wanted to live centrally in an area with cultural amenities and/or mature trees.

“I just didn’t want to have to drive the Henday to get anywhere,” says Caroline.

Dave happened to see a discussion about straw-bale housing on a local website and contacted Battle Lake Design Group the next day.

They’ve now fallen in love with their two-storey, 1,200-square-foot, Mill Creek-area triplex and are building another bedroom in the unfinished basement. Their family might expand one day.

“We wouldn’t want to move,” says Dave.

Private Residence

BLDG — Fri, 17 Feb 2012 19:49:14 +0000

Private Residence, 2005

Stevenson Residence

BLDG — Wed, 08 Feb 2012 03:02:42 +0000

Stevenson Residence owner-built project, 2011.

Devon Professional Building

BLDG — Tue, 07 Feb 2012 04:40:01 +0000

Proposed Devon Professional Building exterior facade renovation, Unbuilt.