So I have 13’6″ to play with. That’s the maximum legal road height that you can have without 1. getting in trouble and 2. hitting bridges.
When my dad and I drove to Ontario for the Tumbleweed workshop, I made sure to pay attention to bridge heights. Some people build a little lower than 13’6″ to be safe, but from what I saw, none of the bridges on the main roads and highways were lower than 4.2m, which is about 13’9″. Hopefully there are no bumps under those bridges, but I won’t be moving the tiny house often so I’m taking every inch of head space I can get.
Some provinces even have a higher maximum height. Alberta, however, sets the limit at 13’1″, which is unfortunate because I’ve heard B.C. is gorgeous. If I end up moving that way, I’ll figure it out then.
Now, the trailer company in N.B. told me that they can’t make the trailer deck any lower than 2′. That gives me exactly 11’6″ for my house.
Here’s a simple drawing pointing out some thicknesses to be aware of:
Now, the trailer will be 6 inches thick (cutting into the bottom two feet, not into the house). I’m going to insulate directly into the trailer. That way, I don’t have to waste precious inches by building a floor frame on top of the trailer deck. But, to get a decent r-value in the floor, I’ll need more than 6 inches. I don’t dare get a thicker trailer because the trailer is already over budget as it is. So I’ll just get 8 inch insulation and trim the edges to fit. It will be a bit of a challenge to get the plywood to lie flat, but it’s doable.
So if the insulation is 8 inches thick, and the plywood and flooring are about 1 inch together, that’s 3 inches that will cut into the house from the bottom.
Next, the rafter ties: I set the top of them at 7′ into the house, and they cut into the lower space by 4 inches. Then say the plywood and flooring (on top of the rafter ties) are again 1 inch together.
Then there’s the roof. I’m not quite sure about all the things that go into the roof, but I have to account for at least 8 inch insulation (which, by the way, is 28 r-value and lower than I’d like), plus the thickness of the roofing at the peak, which can’t go above 13’6″ so it has to cut into the house, plus I read something about needing 1 inch of space somewhere in there. I’ll have to do more research, but for now I’m estimating 10 inches (just a note, I only accounted for 9 inches of roof in the loft drawings).
Okay, with all these accounted for, the main floor is 6’5″ underneath the lofts and the loft is 3’8″ at the peak and 2’8″ at the sides. With a 6 inch thick mattress (though it could be more or less), that makes my head space above the bed 3’2″, just a little bit lower than I’d like.
I think I will lower the rafters by two inches to make the heights 6’3″ and 3’4″, but I want to look into the heights in other tiny houses first and ask my tallest friends their exact heights 😛
Lovely Little Dream 