So, you’re building a tiny house, but what material do you use for the frame? This is a question I get asked regularly and the answer, in my opinion, is simple. When choosing a material for your tiny house frame there’s only one option – STEEL!
When it comes to building frames, I’ve been there and done that. I’ve built new houses and renovations with timber, I spent years travelling Australia building steel framed McDonald’s stores, I’ve even worked on rammed earth projects. I’ll admit that our truck house is the first tiny house frame I’ve built, but a tiny house frame is like any other house frame, with one exception. Most tiny houses can be relocated, and this my friends, is why steel is king. Let us compare the pros and cons of a steel tiny house frame vs a timber tiny house frame.
It’s common knowledge that steel is far stronger than timber, it can withstand far heavier loads due to its higher tensile and yield strengths. Why this is important for tiny house frames is because most of us want our tiny’s to be relocatable, and why wouldn’t you? The ability to pack up your house and move it to a new place with new and exciting opportunities is one of the main draw cards for tiny house dwellers.
Now, imagine your tiny house bumping along the highway to its new destination, but the road is not completely flat. As the wheels of your trailer drift up and down through the contours of the road, your base frame will be subjected to torsional stress, otherwise known as twisting. It may only be a small amount, but if the base of your tiny house is twisting 10mm, the amount of twist at the top of your tiny house frame will be far greater. It may only be a small amount of stress, but it’s happening repeatedly while you’re driving, and don’t even get me started on the effects of vibration! Steel tiny house frames will withstand these stresses far more easily than timber tiny house frames. Timber fixings are not as strong, timber does not like to twist and timber can shrink and deform over the years.
If you’re building your tiny on the back of a vehicle, check out my article on building a torsion-free subframe here
This may be hard to believe, but steel weighs less than timber. Because of its strength, the steel for your tiny house frame can be very thin. Even as thin as 1 millimetre. For our tiny house frame, I’ve used 30 x 30 x 1.6 millimetre SHS (square hollow section) which weighs in at 1.6 kilograms per lineal meter. For the timber alternative, 90 x 45-millimetre pine can weigh up to 3kg per lineal meter. That means a timber tiny house frame will weigh twice as much as a steel tiny house frame. Although using SHS will require the skills of a capable welder, there are plenty of alternatives that don’t require welding, such as BlueScope’s TrueCore framing.
Steel is straighter than timber. This may not seem like a big deal but trust me, building a tiny house frame is much easier when the material you’re using is straight. There’s no need to plane or pack walls to get them straight, wall junctions go together with ease and making the whole structure square is a breeze. A steel tiny house frame won’t shrink, twist or warp, reducing the likelihood of problems such as cracking cornices, jamming doors, sticking windows or wavy rooflines.
Finally, a steel tiny house frame is far more durable than a timber tiny house frame. Steel won’t rot, it’s impenetrable to termites, and it won’t burn. You can drag your tiny house from the chilling winters of Tasmania to tropical North Queensland with confidence. Steel is also recyclable and doesn’t require any trees being chopped down for its production.
A steel tiny house frame may make it more difficult to hang a picture frame, but the benefits far outweigh the negatives.