How to Build a Straw Bale House

For many a savvy self-builder, alternative construction methods for housing are something of an obsession. Low carbon footprint, high thermal mass, reclaimed and renewable materials are all buzzwords which have yet to hit the scrap heap. In fact, ‘alternative’ building methods are gaining a substantial and loyal following; showing no signs of slowing down.

The ‘tiny house’ and ‘van conversion’ movements are capturing the imaginations of the financially-challenged, wannabe home owners around the globe. That’s not to mention the die-hard DIY-ers looking for new projects (and new ways to earn blisters). There are those however, who long for the life-sized 3-bedroom home, and don’t necessarily want their abode on wheels.

Straw bale housing, as we’ve discussed in our previous article, is a terrific way to save on energy costs in the long-term, and can also be much cheaper to build. Making it easier for young people to enter the housing market, as well as helping to keep their energy costs down, straw bale constructions are a dream come true for self-builders looking for a solution which ticks all the boxes. Here, we walk you through the basic steps to building your own straw bale masterpiece.

1. Decide on your size, and make a floor plan

Of course, the first step in any build is planning the layout. While you could have an architect do this for you, true self-builder purists would scoff at the idea. Many websites, including WikiHow are loaded with helpful planning tools and staffed by an avid contingent of contributors who are more than keen to lend their expertise.

Do you need three bedrooms or four? How much land have you got to work with? What size would you like your kitchen and lounge to be?

Needless to say, simple, box-like rooms are easier and cheaper to build; not to mention, less likely to result in tears and hair-pulling.

2. What kind of base are you going to lay?

Before you can begin constructing your dream home, you’ll need to lay the foundations and base. Depending on your local council and building regulations, you may be restricted in the kinds of materials you use. Concrete foundations and base are easy to lay, yet are not the most environmentally-friendly option. Packed-earth is one alternative, yet the use of this will depend on those pesky regulations, so be sure to do your research.

3. Do the math, mate

It’s then time to pull out the calculator and start buying materials. How many straw bales are you going to need? This part of the planning isn’t too difficult, of course. The dimensions of your straw bales versus the size of your plan will give you the final figure for your quantity of bales, whereas rendering/plastering, roofing, plumbing and other fit-outs will depend on how much cash you’ve got to play with. As our mate Kevin McCloud will tell you, having a budget and allowing a contingency are imperative. Fail to plan, and you plan to fail (yeah, thanks Dad.)

4. Build a frame

Regardless of the structural integrity of your straw bales, you are still going to need a frame. Luckily, in the straw bale building process, this aspect is relatively simple. Four posts, one in each corner of the build, and joists to connect these at the height of the structure are all you’ll need to get this project off the ground. Your choice of materials will depend on your budget, and on the strength of your desire to be carbon-neutral. Sustainably sourced timber is light and easy to work with, whereas steel is less forgiving of errors, but longer-lasting and stronger (as well as pest and mould-proof, to boot).

5. Construct the walls

Now for the fun part: Building your straw bale walls. Laying your bales in a brick-wall pattern, ensure that you’re not leaving any gaps (which create draughts, and allow the ingress of mould, and pests). The use of string lines from your frame can help you to keep the bales straight, and with a rather large wooden mallet, you can bang those puppies into submission until they’re in line. Use staves to hold the layers together as you go, and then finish with your chosen render.

You may decide on a cob, or soft plaster finish, depending on your commitment to doing things the hard way. Cob, a mixture of mud, straw and water makes a great, breathable membrane for your walls, however, is quite labour-intensive. Breathable soft plaster can be bought ready-made, and is definitely a much faster (and less rage-inducing) process. That said, slapping wads of cob onto the walls is a job that might keep the kids out of your hair for a few hours weeks. If you’re not concerned about the aesthetics (or if your kids are particularly talented in cob-slapping), cob may be the way to go.

6. Leave gaps for windows and doors

Woops…if you’ve been following this article step-by-step and have put down the computer to go and build your straw bale walls without reading ahead…we apologise. Perhaps we should have mentioned—you need to leave holes for your doors and windows. But frankly, if you didn’t already think of that, you’ve no business on a building site, DIY or not. (And you’ve probably sealed yourself inside the beautifully constructed cell you’ve just created, well done.) Moving along…

7. Organise your electrics and plumbing

Ok, so the electrical component of your build is one area which will require the help of a professional. Go get yourself an electrician and get those power points sorted. Next, plumbing. Right, go hire a plumber as well. Seriously. Don’t try and do that stuff yourself. And no, don’t get Uncle Dave to do it either—as handy as he thinks he is, he’s not going to answer your calls when the cistern busts a gasket in the middle of the night and you’re the proud new owner of a sewage treatment plant.

8. Use a breathable paint to finish walls, inside and out

Once you’ve finished your magnificent straw castle, you’re going to want to put a lick of paint on that baby and make her look a million bucks. Be careful before choosing your paint, as the regular household variety won’t do the job. You’re going to need some breathable paint, as it doesn’t trap moisture within your walls. Moisture is the enemy of a straw bale building. Luckily, this stuff isn’t hard to find. Pick your colours, host a painting party (yes, it’s a thing) and buy a slab of beer for everyone who’s helped you out over the last few weeks. (Maybe hold off on cracking the beer until the painting’s done—unless you’d like a Jackson Pollock-esque, abstract, impressionist finish to your walls.)

Presumably, our expert advice has given you all the knowledge you require to get cracking on your very own straw bale house. We take thank you’s in the form of beer and invitations to house warming parties (so long as there’s beer). You’re Welcome. Happy building!