Tiny House frame, steel or timber? Help!

Hi Everyone,

I am wanting to build my own tiny house and I am starting by doing extensive research. I am already finding a lot of conflicting opinions/information when contacting trailer companies and people to construct the actual frame ( I will have to pay someone to do this as I don't have the skills, time or woman power on my own so I want to choose wisely).

Some companies swear by timber frame and tell me it's the same weight as steel because the steel needed for a tiny house frame has to be thick and strong. These people say that timber has more flexibility when the house is towed and this is important.

The pro steel frame companies say that you DON'T want movement in the frame when towing as that is where good suspension in the trailer comes into play. These people also say steel is lighter than timber.

I have spoken to about 8 trailer makers and tiny house builders and I am totally confused. I am doing this project in Australia and I am finding many builders who claim they specialise in tiny houses are just starting out and jumping on the band wagon as the Tiny House movement is still in its very early stages in OZ.  Any opinions/experiences would be so welcome. I hope to hear from someone about this.

Thanks

I can't speak to steel, but my heavily built wood-framed 26' tinyhouse on a 14k equipment trailer(basic leaf-springs) survived extensive violent fishtailing across 2.5 lanes of a 2-lane highway with zero damage.. can't imagine there was too much movement or the steel siding or windows would be unhappy...


Now that I have established myself as someone who tows things that they probably should not.. I think this choice is not the most critical.

I would suggest you attempt to select an experienced builder with some sort of track record, and have them build the way they are used to building! If there are two choices equal in all other ways... well, someone else will be along with more of an opinion on the steel option I bet!

I have built houses with both.
For a land based home, timber is easier, but a trailer built Tiny house is best with a steel frame.
As a Civil Engineer I can tell you steel gets its strength from its shape and does not need to be heavier material.
Steel is riveted together and with good design will be lighter and stronger than any timber frame.

I do not build Tiny Homes, and steel will be lighter.
The weight of a tiny home can creep up if you are not careful, and then you have registration issues.


On Facebook there was a page for a Tiny Homes Festival in Bendigo recently, you may see some more info there. Contact me if you want someone to bounce ideas from.

With steel you would be able to get it build as sections at a steel frame plant, the rest is straight forward.

Aluminium and wood-composite. At least in my climate.

Steel is a wonderful material if keep away from oxygen, or if it can be sanded and repainted regularly. Otherwise it will loose up to 1mm/year as rust (when salt is involved).

Aluminium holds up much better, but unless it is a marine-grade aluminium, salt is also an issue. So if you may be driving on roads with salt on them, it needs to be marine-grade aluminium. Aluminium also holds up against all the UV radiation here. (Which few paints, that would be required for steel, do.)

I have read great and bad great things on wood-composite. So if you go that route, let the builder show you how their previous projects have hold up after 20 years.

Are you building a house or a trailer? If you plan to move often then weight is important. If you are building a house, insulation becomes important. I have roasted in a hot trailer, then paid a fortune to heat it. Give me good old fashioned 2x6 walls, better yet a double layer 2x4 wall, with triple pane windows. If I’m moving a lot I’ll buy a tent.

Thanks people for the replies. Yes I plan to build a tiny house on wheels. It will need to be towed on the odd occasion ( and maybe quite a long distance) so it needs to not just be legal but strong and as light as possible. This will be a challenge because ideally I would like it to be between 7 and 8 metres long ( 22-26 feet long). I would be looking at building much of the furniture and cabinetry as non fixed ( or easily detached), so if it did need to be towed it can come out and be moved separately to save weight. As it will most probably need to travel on unsealed roads for short distances, I want to make sure I get the frame and trailer right as I know how important the foundation is.
I plan to use galvanised steel so hopefully that should protect from any rust for the rest of my lifetime anyway.
I also want to use non toxic materials for insulation and lining. I seem to have found a plywood that has no formaldehyde so hopefully that will be one of the lighter options to line the interior.

Hi Kate:   Welcome to Permies!

Some good options here for you , Ill add mine.  

In my opinion, no doubt about it... steel / aluminum is a better frame for a mobile home.  
Your tiny house can be build with wood but the frame and suspension should all be metal. Aluminum would be lightest by far but I think pretty costly.
Using a prebuilt equipment trailer like Dillon did (drive carefully) would be a good compromise.  Setting your wood built tiny house on a prebuilt trailer allows you to be mobile at first and later if you find a place you want to stay,  you have it unloaded and set on a foundation. Then you sell the trailer to recover some costs.


I've not given much thought to the tiny house craze. I wonder how does a mobile home deal with service hookups ?   Water , power and most important sewage ? I would think hauling about a water and sewage tanks would add a liquid weight to your vehicle that makes driving hazardous ...  just ask Dillon.

Steel certainly seems like it's coming out the winner for the frame. It's great to get some unbiased opinions.
Thomas, the electrical in a tiny house is often set up with both 12 and 240 volt options, so it can either be hooked up to the grid or totally off grid with solar ( which is what I would prefer) working with 12 v lighting. Cooking, fridge and hot water would be gas or gas/electric option. The off grid power system would be plenty for lights, charging a phone, computer and maybe blend a smoothie each day. Washing machine use might have to only happen on sunny days when there is enough energy and would need an inverter.
Toilet would be compost, there are some really good set ups available. Grey water would be filtered and directed into a garden via gravel pit or sand. I never use chemicals or any products that are not biodegradable and environmentally friendly, so for one person the set up is pretty simple, it's just time and money getting it established. Accessing fresh water is the big issue, ideally if I can find land to park where I can hook up to water would be perfect, other wise it's about collecting rainwater and being very conservative. In Australia Tiny Houses on wheels are not something people take travelling like a caravan, they are usually stationary, so placing a water tank next to the house would solve this issue.

thomas rubino wrote:
I've not given much thought to the tiny house craze. I wonder how does a mobile home deal with service hookups ?   Water , power and most important sewage ? I would think hauling about a water and sewage tanks would add a liquid weight to your vehicle that makes driving hazardous ...  just ask Dillon.

Large tanks would definitely not have helped matters; my setup is pretty much what it sounds like Kate is planning on. External water tanks and composting toilet.

A nasty sudden crosswind from the high side of the shed roof on a 13.5ft high house combined with a bit too much speed on a suddenly increasing downhill grade were the triggers for my excitement... I built it to move by highway ONCE, glad to never be doing that again!

I would go with steel, but I am a welder and not a metallurgist.

I build a lot of my own equipment, and while I do like wood because it is so plentiful, and I have a sawmill to make what I need, most of the time it takes so much wood to get the same strength as steel, that steel is just much, much more easy to work with.

I would not go with aluminum though because it has one major fault...unlike steel, it does not deform before breaking. It just breaks. That is concerning when strength matters.

Travis Johnson wrote:I would not go with aluminum though because it has one major fault...unlike steel, it does not deform before breaking. It just breaks. That is concerning when strength matters.

It depends. Cast aluminium is brittle, but many other forms are flexible. My cargo bike (welded aluminium) had a small accident with a wet cobblestone road, and it only left a dent. The aluminium wire that is abundant here is as flexible and bendable as the steel wire.

ThinHaus builds with steel ... and a lot of tech screws. In fact, there are over 10,000 screws in each ThinHaus. This one is engineered to 150mph winds and stands 13'6" tall on a drop axle trailer. There are a ton of reasons why steel is better, but you have to get past the fact that the material is a bit tricky to get and the skill to build it is uncommon. Once past that, you have something really special.

If you have decided on a steel frame, consider getting quotes to have the frame factory built and fitted to the trailer, or at least made in panels you can fit together at home.
You need to run gromments through any holes in the frame that you pass anything through. Power, water

John C Daley wrote:If you have decided on a steel frame, consider getting quotes to have the frame factory built and fitted to the trailer, or at least made in panels you can fit together at home.
You need to run gromments through any holes in the frame that you pass anything through. Power, water

Absolutely! We use these from Home Depot and Lowes and they work great. Not completely cost free, but at 25cents each, it's a terrific insurance policy especially for a movable ThinHaus.

I am sure a bag of 100 or so would be a lower price.
Try and electrcal wholesaler for them.
They may even be 500 to a bag.

No doubt that this and any other item is less costly if you buy a bunch of them ... and if you are like ThinHaus and make a lot of tiny houses, then maybe you can save. If you are building one tiny house, you probably won't need more than a couple of bags of these. There are many other places to save on your build than spending time trying to save $5 on grommets.