How would you install this ceiling?

[Poorlytiedfly]

I am in mid-construction on my NOMAD build (see my build thread link below) and am having trouble figuring out how I want to install the birch ply ceiling. My issue is that my trailer is 6'wide... my ply is 4'x8'. I know that I can either run two side by side pieces of ply seamed in the middle at 3' or I could turn the sheets sideways and have a seam every 4 linear feet going side to side. Which construction method would be preferred.

Another complicating factor is the profile of my trailer. The "nose" has a relatively extreme bend in it and I don't feel like ply run side to side will bend as much as when it is run length wise. Maybe this is just me....

Your opinions are greatly appreciated.

[halfdome, Danny]

I see what appears as a ledge/rabbet for your ceiling which is a good place to attach your plywood.
I'd go with the 1/8" x 4' x 6' orientation as plywood usually bends best on the width.
In my opinion, it will look a lot nicer than two 3' pieces side by side.
Side by side creates a framing situation that would need to mimic the wall profile so the plywood is tight to the ceiling the full length.
I'm assuming you'll place a spar at each plywood seam.
I always put a 1/4 x 3/4" piece of nice wood trim over the seams.
In my case I only have one exposed seam as I plot it all out to land on top of a cabinet face frame top rail.
I put a corresponding piece of trim at the opposite end just to give it some balance.
Good luck with that extreme radius in front.
Danny

[dogscats]

What are you doing for cabinets ? Can you hide any seams behind .

[lfhoward]

I am also interested in what people recommend. I have similar birch plywood ready to install as soon as I can finalize my solar panel wiring and insulation overhead. Thanks for asking the question. I like the idea of using 1/4 by 3/4 trim over the seams.

Not to thread-Jack, because I think this question applies to yours also, but do people recommend using screws to fasten the ceiling to the spars, or is Titebond II and nails from a nail gun sufficient to complete the task?

[pchast]

Look for bendy plywood. ask at the contractor's desk where you shop.
it is used in construction for tight radius and can be had to bend
either direction.

[halfdome, Danny]

do people recommend using screws to fasten the ceiling to the spars, or is Titebond II and nails from a nail gun sufficient to complete the task?

I use pan head screws as clamps in the middle of the seams and the trim covers it up after the screws are removed.
For the rest of the ceiling use padded prop sticks to push between the floor and the glued ceiling, at the spars, exposed nails are unnecessary this way.
Danny

[LMarsh]

I'm not sure if this applies to birch plywood or just plain old 1/8" but...

As already mentioned the 1/8" plywood is more flexible in one orientation than the other, but it can depend on which way the center ply is running. I've seen it flexible in both directions and some is just plain more flexible than others. I started with some sheets from one lumber yard that was very flexible in the width and it worked great for our 5' wide. I got real lucky with those sheets because then I got some more from a big box store and it busted every time I tried to bend it around the tight rear radius on build 2, I even poured boiling water on it to soften it up. It made no difference though. I finally realized the large center ply was flexible lengthwise in these sheets. They were less flexible overall too, either from the material or maybe a thinner center ply and thicker outside plys. I ended up getting the bendy plywood because I couldn't get anything to bend around the radius. It was pricey and hard to find though. I called every lumber store in the area and only one supplier had it, but all the stores either wouldn't/couldn't get it or were getting it from this single supplier. Since the supplier would only sell wholesale to other businesses I had to buy it from a retail lumber yard but then drive to the supplier and pick it or wait for delivery to the store.

If you have a tight bend as it appears in your photo, definitely look into and consider the bendable plywood. It's so easy to bend you'll be amazed. I believe all the plys run in the same direction so it bends effortlessly. I still have some rolled up into a coil in my garage. You have to specify which way you want it to bend too. The 1/8" bendy plywood is a little floppy so you could even consider something thicker, but once its bent it does stiffen up a bit, just not as much as non bendable 1/8" plywood.

[Poorlytiedfly]

Might be a dumb question but can you kerf cut 1/8"birch... just in the necessary areas to bend extreme curves?

[bobhenry]

Might be a dumb question but can you kerf cut 1/8"birch... just in the necessary areas to bend extreme curves?

I borrowed the neighbors kiddie pool and put my 1/4 luan in the water under black plastic for several hours in the summer sun. I think I could have tied it in a knot after it's steam bath. It dried well and without any noticeable harm to the material or the finish. You might test a small piece to be sure it will work for your choice of materials.

[elcam84]

The bendy ply mentioned is good stuff and available in many sizes. Also Baltic birch comes in 5'x5' sheets as well as 4x8 now and sometimes 5x8 and 5x10. Look for hardwood suppliers as its used in woodworking. Locally I use Sweeney hardwoods and plywoodcompany.com (fort worth plywood ). Sweeney delivers with a $100 order can't remember how fort worth plywood does theirs as its been a while though I'm going to order 200 bf of cherry to finish the kitchen cab doors and drawer fronts. They also carry 5x12 particle board which is great for building surfaces due to its size and flatness.

[Tomterrific]

When I tried to bend my top sheet of underpayment over a 28" radius it was too stiff for comfort. Solution? I pre bent it. I left the sheet of ply half bent over night using ratcheting tie-downs to keep it in tension. This pre bent the ply and it was much easier to get it in place the next day.

T