Straw bale construction is a way of building homes that’s bursting with energy-efficient promise, beauty and flexibility. Straw Bale Building is one of the easiest homes you can build. It’s almost like an Ikea kit, just put one bale on top of another and layer them until you’re done. But it’s not that simple…if you want a strong structure, you’ll have to do some work.
Building a straw bale house is a much more affordable way to build a home than conventional housing. The houses are attractive, healthy, and can be built by the homeowner with little or no experience in construction. Straw bale construction uses natural materials that require very little energy to produce or transport, which reduces the cost of building.
Building with straw bales is as easy as stacking bricks and plastering over them. They are a truly sustainable building material because they are made from the byproducts of wheat production, can be used for more than one purpose, and require less energy to produce than other building materials. While the time it takes to build a straw-bale home depends on your project scope and complexity, most homeowners can generally complete their project in about four months.
Set a foundation and frame support walls.
The foundation of your straw bale house is extremely important to the structure’s stability. Choose a site that has good drainage and is flat. The site should not be near any trees or structures, including paved roads or driveways, as this may damage the straw bales during construction.
Your foundation should be level and at least 6″ thick. In order to ensure proper drainage, it should be built with a concrete slab on top of some sort of base layer (like gravel) that extends out from under the rim joists into either side wall by about 3 feet. If your foundation does not extend all the way up underneath each end joist, you must create openings for air circulation via gaps between wood frame members (usually 2x4s), so look for these in plans supplied by whoever built your home’s frame before purchasing materials such as cement board sheets or insulation boards because they won’t fit properly over existing framing unless there are also openings between them.
Stabilize the foundation or slab.
If you are building on a foundation, or to be more specific, if you are building on a slab, then it is important to stabilize it. Stabilizing the slab will help prevent cracking and damage in your house later on. There are two main ways to do this: using concrete blocks or cementitious foam.
- Concrete block methods: If you have chosen to use concrete blocks as your foundation, there are two ways that they can be stabilized during construction. You can use steel strap anchors that fit into holes drilled into the blocks (and filled with concrete). Or, you can set metal straps around each individual block at their tops and bottoms after they’ve been poured (this option requires more detail work as opposed to simply pouring them all at once).
- Cementitious foam methods: Another option is cementitious foam which has been injected into each void between each course of bricks used for this method creating an added layer of protection against any movement happening within these voids over time while also being lightweight enough so as not destroy any structural integrity from occurring within those same areas because its application takes place before any actual building begins taking place atop these foundations themselves.
Install floor joists, beams, and girders.
The following steps will help you install floor joists, beams, and girders.
- Use 2-by-10 joist hangers to support the floor joists. Install them perpendicular to the ends of your wall with their lip facing down in order to hold up the weight of any roof or ceiling material that will be installed on top of them later.
- To create a strong support structure for your rooms, use 2×10 beams as supports for your floor joists. These can also be installed perpendicular to each other at every point where two walls meet if you want more stability in those areas (for example: around windows).
- The third step is to install a girder at each corner of your house where two walls meet so that they touch each other—these are what hold up all four corners simultaneously and make sure they don’t fall apart over time due to wind gusts during storms etcetera.
Add in plumbing, electrical and insulation.
The next step is to add in plumbing and electrical. This is no different than any other house, except that you’ll have to be careful with your plumbing lines because straw bales are slightly absorbent. If you’re building a small, single story home like ours, then all of your plumbing lines can run through the floor joists instead of through holes in the wall. You will also need to install an airtight door and window for each room so that moisture doesn’t get inside during winter months when exterior walls aren’t exposed (more on this later).
The last step before moving into your new home is insulation—just like any other house! However, because straw bale houses are typically built without insulated foundation walls or basements (which act as insulation), they require more insulation than traditional homes do—typically between R-30-R-40 SPF (for example: 11 inches of cellulose). In addition to this thick layer of insulation on top of the foundation wall (between studs), it’s recommended that homeowners also DIY their own thermal breaks at ceiling intersections where two different materials meet; this helps prevent heat transfer between them by creating an air gap between surfaces which helps keep warm air in cold rooms and vice versa within hot rooms. It’s important not only because it provides better comfort levels but also reduces heating bills too.
Lay down your straw bale walls as square to the floor joists as possible.
Straw bales are an excellent building material for insulation, soundproofing and thermal mass. The wall cavity also acts as a moisture barrier, which makes straw bale houses more durable than timber-framed houses in wet climates. And because they’re made from renewable materials (straw), they’re sustainable—which adds another dimension of value to your home investment.
Put in plaster to hold the straw bales together.
The next step is to apply plaster to the straw bales, which are now stacked and tied together. Plastering will hold them together and make your home waterproof.
To apply the plaster, use a trowel to spread it on all sides of each straw bale. Then smooth out any lumps or rough patches with another trowel so that there’s an even layer throughout. Let this dry for several days before applying more layers over top of it—in total, you’ll need about 18 applications for a single wall (you may want more if you’re using thicker coats).
Use mortar to bond another wall to the straw bale wall if you want to add one.
When you want to add another wall to your straw bale house, you’ll need to use mortar. Mortar is a mixture of sand, lime, and water. It’s used for bonding bricks, stones and other masonry units together and filling in the gaps between them.
Mortar can be purchased from your local home improvement store or made at home using these ingredients:
- 1 part cement powder (the kind that goes into concrete)
- 3 parts sharp sand (sand with no clay in it)
Add 2x-4″ wood studs at 18″ on center if you prefer a traditional framed out look for your walls.
You may want to consider adding 2x-4″ wood studs at 18″ on center if you prefer a traditional framed out look for your walls. Wood studs are much easier to work with than straw bales, and they will also help make your home much stronger. You can use the wood studs to make doors, windows, or other openings in your walls so you have more flexibility when designing your home.
Building with straw bales is more efficient than many realize, and not that hard.
Building with straw bales is more efficient than many realize, and not that hard.
Straw bales are a great alternative to traditional building materials because they’re cheaper, easier to work with, and more sustainable.
Straw bales are also a renewable resource that can be grown on your land or purchased from elsewhere (like the local farmer’s market).
Finally and perhaps most importantly straw bale houses are incredibly energy efficient because they naturally trap heat in during the winter months through thermal mass and insulate against cold winds in the summertime by trapping warm air inside their walls.
We recommend that you take the time to educate yourself about this type of building if you are interested. It can be very rewarding, and even though it requires more planning and maintenance than a conventional build, the long-term benefits are worth it.