Fire-resistant homes can be built with straw bales

Anne Atkins, center, is seen in a photo taken during the installation of straw bales at her home during the build in 2008. Suzanne Moramarco photo

Anne Atkins held an open house Jan. 20 at her ranch to let people know about the benefits of building homes with straw bales, a subject she is passionate about. She first learned about straw bale building from an article in an Orange County newspaper.

Atkins lived in Huntington Beach at the time and had been saving pages from magazines with ideas for her dream home. The benefits of constructing a house with straw appealed to her and she researched the subject, going as far as Sacramento to attend a straw builders’ convention.

In 2007, she and her husband, Bob, bought a property in Rainbow with plans to build their home. However, before they could obtain a permit to live in a trailer there, the Rice fire burned through the area, destroying their trailer and five houses in their neighborhood that October.

The Atkinses were able to have the property cleaned up and graded by the end of 2007 only to have construction delayed by rainy weather throughout January 2008. The foundation was poured the following month.

At the open house, contractor Tony Flynn from Ramona showed visitors a slide show of photos taken during the building process. Flynn has built several straw bale houses besides the Atkins home, which Anne designed and helped build.

The concrete slab was heavily reinforced with rebar. Unlike the garage, which was built with regular framing (2×4’s and plywood), the house has steel shear walls besides wood framing and beams around the perimeter on which rest pre-made wooden trusses that support the roof.

Before constructing the straw bale walls, a concrete trough was lined with a treated base plate covered with tar and a layer of gravel. When the bales are pounded into place, there are no gaps of air. Flynn explained that any moisture that may collect on the straw within the walls will drain into the gravel where it will evaporate.

To fill spaces smaller than a straw bale, a bale is cut to size after being rebound with a special needle and cord, then beaten into place with a large mallet. When all bales are in place, they are bound with chicken wire then coated with cement stucco, 7/8 to 1 inch thick on the outside and ¾ inch thick on the inside.

The Atkinses moved into their finished house July 10, 2008. While the cost was a little higher than a normal build, Anne said, the insulating function of the straw bales keeps the inside temperature constant, saving on heating and cooling costs. Solar panels on the garage roof and the use of propane gas for the stove, drier and water heater also help make the 2,300 square foot home “affordable to live in,” she said.

Because straw is not edible, it does not attract insects or rodents. Without air in the walls, there is no oxygen to allow a fire to burn the straw. That also means there is no heat lost or gained through the walls which can still breathe without moisture building up in them. The thick walls also serve as a sound barrier; from inside the home, the noise of vehicles on the nearby freeway cannot be heard.

The interior walls of the Atkins’ house are conventionally built but do have built-in niches in the living room that echo the inset windows opposite them.

Flynn explained that the window glass is placed at different depths within the two-foot-deep window openings, depending on which direction they face and where the house is located. In southern facing desert homes, windows are installed close to the inside edge of the openings so they are shaded by the walls, not just the roof.

On the north side of a house, the window glass is placed closer to the outer edge to take advantage of the sun and bring in more light. The straw bale wall below the windows creates a natural window seat.

Instead of curtains, the Atkins’ use specially built metal shutters, hung outside above the windows, which they roll down at night and then back up during the day as the sun moves. This not only helps keep the house a comfortable temperature, it also makes it more fire-safe.

In the event of a fire, the shutters can be closed so that no heat can penetrate the windows. To make the house even more fire-safe, the Atkins had sprinklers installed in the outer edge of the roof that can spray water up on the roof and down at the foundation. This feature also earns them a discount on their homeowners’ insurance.

The water from the sprinklers comes from three sources Anne said. Besides the municipal water supply, they have an irrigation well and a pool (aka cement pond) up on the hill above the house. The pool has enough water to spray the house for three days in the event of a fire.

There are more details involved in building with straw bales which Anne

encourages anyone interested to research. A wealth of information can be found online, in books and at workshops.

Before building though, financing is another subject for research. Steve Lewis, the Atkins’ mortgage loan originator, was also at the open house to talk about sources of loans for home building.

There are options for homeowners who lost their homes in the Lilac fire, Lewis said. The 203H program through HUD and SBA do not require mortgage payments up to a year. He added that there are also loans available for fixing partially damaged homes too. Federal Housing Administration 203K loans can fund a new kitchen or to add solar panels. A homeowner can borrow up to 110 percent of the completed home’s value.

In San Diego, Lewis said, loans can be made for up to $649,750, unlike Riverside County, where the loan limit is $453,100. Loans can be as small as $5,000 or up to $35,000 in the 203K program. In these kind of loans, he explained, the lender insures the contractor is paid and the borrower is protected because the contractor is not paid until the borrower is happy.

There is a lot to learn before anyone starts to build a straw bale house. What is important, Anne said, is “knowing what you want and your financial limits.” She is willing to talk to anyone who wants to know about the whole process. She can be reached at­­­­ (760) 216-2016.

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