floor framing for a trailer tiny house

[erin85]

Hi guys! Maybe a noob question here... we are building a tiny house on a trailer next year, and I think I have a good idea for adding a couple inches of head room (I am limited to total height 13.5', including sleeping loft). Here's the trailer we plan on using: http://www.tinyhomebuilders.com/tiny-houses/Trailers

Instead of doing the floor framing totally on top of the decking, as usual, I was thinking it might be possible to incorporate it into the existing design -- that is, put the floor joists in so that they are perpendicular, but no taller than the 'steel beam decking' in the picture. I was convinced by a previous post on here than steel studs are really cool, so I plan to do all steel framing. We'd put the insulation in as well, then cover with plywood subfloor (at least 3/4") above, overhanging the steel flange sides. Aluminum flashing or similar would be below the studs for waterproofing (between the decking).

What am I missing here? Why do people usually do a full floor frame above the decking? Does this make it extra difficult or impossible to secure the walls? The few inches that I could save by not doing a full 2x4 frame above the steel would be nice!! Thanks for your help!!

[Don_P]

Yeah, I'm not really liking their trailer, it looks like they've added a structure on top of an existing trailer.
If you use 6" C channel with the smooth side out and the flanges turned in for the outer rim, the spring hangers mount to it and it forms the tongue. Then use 4" C channel to form the crossways ladder framing, your joists, welded to the inside of the  6" this would make a very rigid frame. Drop the 4" channel 3/4" below the 6" frame and deck to the 6" flange. Skin under the 4" joists and you can put in rigid insulation. I was not suggesting metal stud framing, I was talking about square steel tubing, you can weld it to the 6" flanges of the rim frame. Metal studding could be used for infill framing within the structural steel frame.

[cbc58]

Erin, you may want to look at this tiny house build for info and ideas:   http://www.protohaus.moonfruit.com/#/protohaus/4534267679    13.5' is MAX height and you probably want to go abit shorter to be safe.  There are also many Tumbleweed homes for sale so if you can actually get in one and "feel" it... that might be very helpful.     

[JRR]

A DIY trailer house might be nice, but a lot of work before you begin travelling.  On the other hand, if you think in terms of a converted bus ... you can hit the road the day after purchase, if you select a bus "ready for the road".  First trips = bare camping.  Later trips, after you've fully converted = high style living!

A primer:. https://www.google.com/search?q=school+bus+conversion&tbm=isch&tbo=u&source=univ&sa=X&ei=k0DQUdnUL4vu9ATTrYDABQ&ved=0CC0QsAQ&biw=1536&bih=769
.
and:. http://www.instructables.com/id/Re-use-a-Schoolbus-for-Cheap-Housing-Prologue/
.
... just a thought.  Be sure to plan carefully ... check with your insurance guy ....and check with local authorities about road use/licensing/parking/etc./etc.