Expert Advice on Straw Bale Construction

Read surprising answers to common questions about straw bale construction, an increasingly popular alternative building method.


| February/March 2006



Kanata Straw Bale Home

Here is a straw bale home in Kanata, Ontario.


CATHERINE WANEK

Houses made from straw bales are attractive, affordable, energy efficient, environmentally friendly and can be designed to match the owners’ personal needs, aesthetics and budget. These homes are made by stacking rectangular bales of straw and covering them with a plaster shell. Straw bale walls are at least twice as energy efficient as those from conventional stick-frame construction and will save you money on heating and cooling bills. Such savings are among many reasons why straw bale construction is no longer a fringe idea, but one that has spread throughout North America and the rest of the world. Other attractions include its adaptability, hands-on building satisfaction and the cozy atmosphere created inside these homes.

With this recent surge in popularity, the collective knowledge built from the successes and mistakes in this grass-roots movement has helped the technique evolve — we now know much more about what works and what doesn’t. So before you decide if straw bales are right for your dream home, heres’ expert insight into common questions about fire resistance, moisture, pests, building costs, mortgages, insurance and resale value.

Fire Resistance

Straw bale walls are naturally fire resistant. Loose, dry straw is combustible, but when it is compacted into bales, there’s not enough air for the straw to burn well. For a good analogy, compare the combustibility of a single sheet of newsprint to that of an entire telephone directory. A single sheet will burn quickly, but a phone book will just smolder. Combining plaster with the compactness of a bale wall enhances fire resistance. The plaster coating effectively seals the already fire-resistant bales inside a noncombustible casing. According to fire safety tests conducted by the National Research Council of Canada, bale walls withstood temperatures up to 1,850 degrees for two hours.

reneeb
4/25/2015 12:27:05 PM

Reading through the comments I see one person using rice straw. I was going to say I have seen rodent damage in any hay or straw we have always had so I doubt that rodent damage is eliminated/minimized with straw bale construction. However rice straw which is very available in our area might be different. So that question is off the table. I have 2 other questions: what about moisture in the bales themselves? There must be some moisture in the bales. the last question is how does one hang pictures in straw bale construction? Picture moulding? I can't imagine that it's good to poke holes in the plaster and expose the straw. Thanks!


donald
4/22/2015 6:36:13 PM

I use rice straw bales as a very strong wall around my outside space. It has been up for nearly 10 years without any problems. The space is 50' by 70'. Rice straw has a silica base and nothing I have seen eats it. My horses will eat just about anything and they won't give it a second look. My wall cost $4000 which included transport to my house, unloading, and placement of the bales. The main cost is transportation. The bales themselves are cheap (between 15 to 20 dollars for 1500 lb bale).


katie
11/21/2013 3:28:54 PM

Can you build bales with cob over an existing home? My house had been on fire before I bought it, and the previous owner did not use insulation. Thus, my zone 5 home is only tolerable upstairs during Winter with the thermostat set at 55 and it is 70 upstairs. Vice verse in Summer. Any suggestions?


wildflower49
11/7/2013 2:01:58 PM

You skimmed lightly over the subject of obtaining a building permit, falsely indicating that that wouldn't be an obstacle. I do wish you had addressed that issue as my experience indicates that most building inspectors and permit issuers ~ like lenders and insurance companies ~ are NOT willing to accept new concepts without the builders having to jump through hoops, and then still be rejected.


christian kimber
1/25/2013 6:24:32 PM

In response to Melaynes heating question, I just built a strawbale house in SE British Columbia (rocky mountains, real winters and dry summers). We installed an annualized geo-solar heating system. Hot water for the domestic hot water (DHO) and the radiant floor heating is supplied by the solar panels on sunny days and a small geo-thermal system otherwise. Excess summer heat is stored in the geo-thermal component, making it a lot more efficient come winter. There is an electric hot water tank as a back up. Total cost was about $25k, it probably consumes about $600 in electricity per year (heat and DHO for a canadian climate).


david sutter_2
8/8/2010 9:04:39 PM

I live in an older mobile home that just bakes in the sun. I have thought about using insulation panels and siding to improve comfort but the bale construction sounds much more effective. Has anyone used bale construction to add insulation to an existing structure?


melayne pritchett
7/8/2010 11:17:36 AM

I am very interested in straw bale constructed homes. Most of the information that I have gotten has been off of the internet and has been truly helpful. I have 2 questions that I would like to ask...First, since I live in Ohio the weather is variable in summer and winter. I was wondering which is the best heating systems to use in this type of home? I am wanting to go as green as possible (have plans to use solar energy) we use wood heat right now and would like to continue to do so but what kind of extra precautions do I need to take with this. Second, this type of construction is not well known around here or accepted, my questions is what is the normal price for bales? From what Ive read so far I want rectangular bales that are dense and preferably made out of wheat stalks. I don't know of any farmers in my area that farm wheat so where would be the next best place to look? Thank you for your time, Melayne






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