4 x 9 plywood

Depending on what kind of a joint you make, splicing can be perfectly fine. A properly made scarf joint, for instance, will be as strong as the base plywood. Making one would require the construction of a jig or two of some sort, or using one that someone else has made.

A scarf joint is basically just a very shallow angle wedge or miter sort of joint, typically something around 1:8 or 1:10 rise to run. For 1/4" plywood, it should be possible to cut the angles with a Skilsaw and a suitable jig; though I'm speaking not from experience but only from thinking it through as I'll also be replacing my motorhome's roof this year.

I like the "Marine" suggestion too. and make sure it is MARINE grade as well. Stands up to weather better.

We get it from a large lumber supplier in the DFW Texas area. Retail cost(what we would charge over the counter and what Insurance pays us on roof jobs) for a 4 by 10 foot sheet is $56.68. Doug

tim-n-tn wrote:
I'm trying to re-roof my 94 gulfstream conquest that is 8'5" wide w/ 1/4" luaun. I've tried lowes and home depot and they do not offer 4 x 9 or 4 x 10 sheets. any suggestions on where to find this? My other option would be 4 x 8 sheets with a brace between the rafters to splice an 8' sheet to the 5" piece so that it is fully supported underneath. any suggestions will be appreciated! Thx, tim-n-tn

You can find the right sized sheets (and proper fasteners) with a little searching. IMO, splicing shorter sheets together would be a VERY BAD idea. In fact, you should cut the replacement sheets (as necessary) as closely as you can to replace the existing sheets. IMO, any future soft spots in your roof are a bad idea.

Chum lee

You'll have to order it if you buy from Lowes. Try a place that caters to builders and contractors.

Also try a place that sells marine plywood to boat builders.

Try your local lumber yards, not home centers.

What your looking for is commonly called Door Skin and is used to skin hollow doors.

I'm sure you can order 4X10 sheets of Lauan plywood but it will be costly. Since your roof is going to have pieces butted together anyway, using 4X8 sheets with a 5" piece spliced in there will be fine and will be much cheaper. I would suggest using a narrow Crown Stapler to attach the Lauan to the rafters. If you don't have one, Harborfreight sells one for under $30 Crown Stapler I have a Porter Cable Crown Stapler that I always use when working with Lauan but for a one time project, the Harborfreight gun is good enough.

I read your post and,out of curiosity, went on google and typed “who sells 4x10 sheets of plywood near me”. I got quite a few suggestions.
Good luck.