rather than a layer of plastic behind the plaster. Applied to the interior plaster of your walls, the paint can achieve a high degree of protection against moisture migration while avoiding the difficulties of working with a vapor barrier over the straw. You might also decide to apply different vapor retarding strategies in different areas of your home. Bathrooms and kitchens are especially prone to high humidity and can be sealed with more vigor than other areas.
Build to Your Level of Comfort
Bale homes have been built both with and without vapor barriers. To date, only direct water leakage into the wall or rising damp from foundations have resulted in damaging deterioration of the straw. But with no complete set of data from which to work, you must decide how to build to your own level of comfort and protection. Real-life experience has indicated that both unbarriered and barriered homes operate within reasonable levels of moisture content due to vapor penetration.
Building Practices that Minimize Rainwater Penetration
Many simple, effective building techniques are used to protect bales from exposure to moisture. Generous roof overhangs and proper eavestroughs eliminate most direct rainfall and splash-back from reaching your walls. A bale wall that is raised on a wooden curb on the foundation or floor allows any spills or floods inside the house to drain away before they soak into the walls. Plastic or tar paper placed along the top of the walls helps shed any water that may someday come through your roof. Windows and doors can be detailed to incorporate proper flashing and drip edges that shed water away from the walls.
Insects and Pests
Let’s face it: we share this planet with billions of other creatures, both large and small. To say that a particular house or style of construction is pest proof is to ignore the intelligence and persistence of our “little neighbors.”
What Are Pests Looking for?
To be suitable for sheltering pests,our homes must offer them openings, nests, and food. Plastered bale walls are short on all three, since their plaster coating seals the bales from foundation to roof with a difficult-to-chew barrier. Should a gap be left open in the plaster, the bales themselves are too densely packed to make comfortable housing for mice and other rodents. All those comfy spaces in your neighbor’s frame walls, lightly packed with batt insulation, make a much more inviting home.
There is little food for any living creature in a straw wall; even termites tend to eschew straw. An inordinate amount of seed head in the straw does provide a good source of food, which is why you should check your bales for excess seed content before purchasing them. Care should be taken — as with any style of construction — to keep pests out during the building process.
While we have heard of very few pest problems in bale walls, that doesn’t mean pests won’t live in your roof, floor, and basement!
Mortgages, Insurance, and Resale
Perhaps the most difficult part of building with straw (or any other alternative materials or ideas) is presenting your project to the various institutions that often must be involved. Lenders and insurers are, by their very nature, conservative and averse to risks. Any construction method that is perceived as new or experimental can seem to them like a risk they’d rather avoid. It often takes time and no small amount of educational effort on your behalf to negotiate for mortgages and insurance for your project. All the evidence exists to convince them that your proposed straw bale house will be a safe prospect for them, but you will have to be the one to present it to them.
It’s Not Impossible to Get $$
Obtaining a construction mortgage, even for a conventional structure, can often be difficult, especially if you are planning to build for yourself. Banks are wary of construction projects because an awful lot of their money goes into the project before it becomes a home with any appreciable resale value. During construction, their money is in a risky spot, and they must have confidence in you, your abilities, and your overall plan. They must also have confidence in your financial situation. So you enter this scenario with several potential problems to overcome, never mind your plans for straw bale walls.
Don’t panic! Many bale builders have obtained financing from regular sources. There are many things you can do to help your situation. First, it will work in your favor to bring the lender a good set of building plans that are professionally drawn and appear thorough in all their considerations. So will a thorough and realistic budget and timeline. Ensure your budget contains guaranteed quotes for materials and services you’ll require. If you are a first-time builder, you may need to hire professional consultants to show the bank that there is good help available to you should problems arise. If you are hiring a general contractor to build your home, he or she will have to fill out paperwork for the bank too. Hiring someone with a good local reputation will certainly help.
The US Department of Energy has published positive findings about straw bale construction, and other government agencies have also done preliminary studies on straw bale with positive results. The CMHC (Canada Mortgage and Housing Corporation), which helps set many of the standards used by lending institutions in Canada, is quite supportive of straw bale construction, and their data can be used when negotiating for a loan. Government facts, figures, and opinions can be powerful tools when you’re dealing with lenders.
Many bale builders have had to approach numerous lending institutions to find the right combination of personality and corporate culture before they secured funding. Don’t let a rejection put you off. If you truly are a good risk, eventually somebody will lend you the money. It takes thoughtful preparation and patience to explain straw bale construction to a lender.
Obtaining a building mortgage is one thing; living by its strict guidelines is another. Building mortgages come with strict pay-out schedules, and money is only advanced to you when you have completed each phase to the lender’s satisfaction. They will also determine percentages of the overall budget that can be used for certain expenses. For example, they will determine how much of the overall amount you can spend on windows. So your initial budgeting may need to be adjusted to work with the lender’s guidelines. The lender will also hold back the final portion of the loan until they are satisfied that the project is complete. Building with a conventional construction mortgage is often stressful and occasionally requires that you have other means of financing when delays or unforeseen expenses arise.
As the number of bale homes continues to increase, it becomes more likely that a financial institution in your area has already lent to a bale home builder. Some research into existing bale homes in your area can lead you in directions where the doors have already been successfully opened to straw bale buildings.
Research Lending Options
There are many excellent references that describe methods and means for obtaining financing. Read widely before you plunge in — and remember, numerous options are still available to you should you receive an initial negative response from a banker. People have financed bale homes in all kinds of creative ways. Some have applied for numerous credit cards and run them to their maximums to build the house, and then consolidated their credit card debt with a single financial institution at good rates, using the completed house as collateral! Lines of credit can be put to use, as can retirement savings plans. Be sure to fully research any and all programs and incentives that might be offered by government agencies in your area.
Insurance
Insurance companies are concerned with facts and figures that indicate levels of risk. The existing research for straw bale homes scores positively with most insurers, especially the excellent fire ratings. Many insurance companies already have these test results on file; others are willing to consider them if you submit them with your application.
Building code approval