Framing, Insulating, and Waterproofing Questions

[sterrell04]

Newbie here.

Skins are off, and we are going to do as much framing as possible this weekend with cooperation from the sun. I have a couple of questions regarding building the framing and ensuring that it is waterproofed at same time before putting skins back on.

Which kind/size of wood is preferred for walls, floor, and ceiling? I assume from reading either 1/2 pine or birch for walls, simple ply for ceiling, but I am not sure about the floor.

Where is the best place to buy the lumber?

Is it best to work from the floor up? Floor, side walls, then ceiling?

What is best method for waterproofing? Should it be done before construction or after frame reinstalled? Is tar or "stain" like material preferred?

Which insulation is preferred and how much is needed for compact?

Thanks in advance.
ST

[schweetcruisers]

Don't use birch for framing, it's to hard and there for prone to cracking when working with it. I recommend using cvg pine(clear vertical grain) doug fir or poplar. They should be readily available at your local home center or lumber yard.

As far as water proofing the framing, not many of use do that, I would recommend a vapor or moisture barrier instead of slapping tar on the framing.

Ridgid foam insulation it the prefered insulation.

[sterrell04]

Thanks for the advice, Schweet. Is 1/2 the normal size for cvg pine? Is moisture barrier just sheeting between frame and skin? What is preferred method for this?

[schweetcruisers]

1x CVG should be 3/4"...but at home centers I think it's 5/8".

I prefer tyvek or typar(off brand tyvek) it goes between the framing and aluminum skin. It designed to breathe, so it lets vapor out but won't let moisture in. I install it by using 1/4" staple from a arrow staple gun. Just make sure to tape your seems and staples with the Tyvek brand tape. Also do the sides first and then overlap the top on the sides.

[mobiltec]

Howdy,

I used 1x2 and 1x3 pine to reframe my Shasta. In some places I even used some 1x4 if I remember right. Total thickness is actually 3/4 inch.

A pocket hole jig comes in real handy for framing these babies up. They are sold at Harbor Freight for about $70. Less when on sale. Look them up on line to see how they work.

And if you have no idea what you are doing you might like some of my videos which are on my website. They are all You Tube videos and free of advertising so I don't make anything on them.

If you know exactly what you are doing then don't bother with my website. LOL....

[Hamlet]

We used mostly 1x2 pine for Hamlet. There were a couple places we went bigger - one was in the bathroom to hang the tankless water heater.

As far as the sequence, it depends a lot on how far down you have taken the trailer. In the originals, the walls were constructed separately, including the birch. They were attached to the floor (which already had the flooring installed on it), and supported while the crossbeams for the roof and front and back were put in place. Then the birch for the ceiling/front/back. Then the cupboards, benches, etc. The structure is quite flimsy until all the pieces are in place. It's rather remarkable, really.

If you are not taking it all the way down and are leaving the skin mostly intact, I will defer to the experts who have done theirs that way...

[sterrell04]

Hey guys. Thanks for the replies. It's really good to hear that 1x2 and 1x3 pine is fairly consistent, as that's what I thought to go with.

Mobiltec, I've seen a few of your videos and they have been very helpful so far, but I'm really just starting out (demo and skin removal). I will be getting a Kreg as most suggest today before diving in.

Hamlet, thanks for your thoughts on the sequence. I intend to do a straight build up, attach walls to floors, then crossbeams for roof, front, and back, then paneling for ceiling, front, and back.

What are your thoughts on the floor? I only have small section that needs repair. Should I piece in a plywood or try to replace a large rectangular section the whole width? Any preferred lumber for it that might be different and stronger?

Thanks,
ST

[mobiltec]

One HUGE thing I would do differently on the next one. If your floor is made with a layer of Celotex and a layer of 3/8 plywood I would forget about the celotex and replace everything with 3/4 inch exterior rated plywood. That celotex was a bad idea and as it setlles the floor becomes loose and you get the "Floating Frame" syndrome.

If you are taking the walls down you will find that they do NOT sit on top of the floor like in a house. They are fastened to the SIDE of the floor framing So even if you do not remove the walls, as long as you take the top off so you can remove the BIG floor to ceiling cabinet, you can replace the entire floor with 3 sheets of 3/4 inch plywood cut to the width of the trailer. I would also add framing as shown in my videos... Here's a photo...

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[Hamlet]

Hamolet agrees with mobiltec. It's not really all that bad replacing the floor. Lots of folks will do a patch, which works in most cases, or they will add 1/4" luan over the floor then another layer of flooring. Also works, but every time you add a little to the floor, you take away height at the ceiling. Not a problem if you're comfortably under 6', but more than that and your head starts to feel a little close to the ceiling. Just something to think about.

[cowcharge]

Hey, welcome to Shastaholics Anonymous. Doughnut?

I used 1 x 2 for the wall framing and 2 x 2 (actually 3/4" x 1.5" and 1.5" x 1.5"), spruce ripped from regular Home Depot 2 x 8s. If you're just replacing small pieces of the floor, you can cut the plywood flush with the closest good frame, and then just add a doubler to the frame so the edge of the new plywood patch has its own frame to sit on. That way you don't have to try to cut the plywood halfway across the frame.