OSB vs PLY For Floor

[Dale M.]

What would be best material for floor... I have a 58"x108" frame so a 4' x 8' sheeting is going to be a little small...

Was looking T&G sub flooring (ply) at 1-1/4" thickness but in my mind its a little heavy (thick) other option was OSB, there is a 3/4" T&G available but I was wondering about longevity of it... Never really used OSB for any construction , but the T&G aspect seem simpler to use to splice some extra on main sheet to have solid floor. The product information says the glue is "waterproof" (like as in marine grade or outdoor plywood - maybe)...

Also think the T&G aspect of construction would make stronger joint and would not have to deal with trying to router a groove along edges to splice sheets with a "spline"...

Anybody use OSB, would you use it again on another build, did you throw a couple of coats of paint on it (bottom) before bolting it down?

Dale

[boujei]

I intend to use the osb t&g underlayment that's at the big box store for my rv build. I'll either use snowcoat or stick n seal to waterproof the underside. After seeing the yacht that was built with osb (guy who brought it into the world had a yacht made of it to prove it's usefulness) I'm convinced that with the proper waterproofing it's as good as ply. (no voids in osb) If I end up making a wrong decision al the nay sayer's can bring burgers and dogs to the bbq that will be along the roadside on US 95 in Idaho!

[Kharn]

A biscuit jointer would let you easily join two sheets of ply together, or could you find a specialty plywood place and buy a single 5x10' sheet.

[boujei]

You're right..forgot about the dimensions. My floor is on a Class C motorhome chassis...8' wide. Still need to build a TD for weekend elk hunts.

[Dale M.]

A biscuit jointer would let you easily join two sheets of ply together, or could you find a specialty plywood place and buy a single 5x10' sheet.

Want to loan me your biscuit jointer...

Dale

[Big Dave]

I used 3/4" CDX plywood for my floor (5x11) and immediately regretted it. It warped and was full of voids. I had looked at the Advantech OSB, which is waterproof, but the OSB part scared me off. I will be using it for the rest of my build.

[Lgboro]

What is the estimated weight of a 5 x 9 tear built with OSB? Must be a really high number? Sealed it should hold up though.

[Dale M.]

No really worried about weight at this point... Floor is point everything (above frame) attached to so I want it firm...

Dale

[Bohemian1946]

Here's my chime in. I was a general contractor and cabinet maker for 33 years and I feel I can give some good advice on the question. OSB is designed to provide share or verticle strength to a structure. I have not seen it used as subfloors, although it is used for roof sheeting but again for it's shear strength value.

The general rule for plywood used for sub flooring is the more layers of plys the better. Lumberyard/general construction plywood somethies comes new to the end user with a built in warp, which is a little problem in construction as subfloors generally and glued down and then nailed with a 4" to 6" O.C nailing pattern to a beefy floor joist.

Cabinet grage plywood is not exterior rated. It is prone to delamination after several years of exposure, and it costs a lot of time and materials to make it semi durable.

So what's a tear builder to do? My suggestion is to buy the more expensive marine grade plywood. It has inctedible strength, and is made from very high quality wood. The sheets are nearly always flat and without warping. Well worth the extra cost

[2bits]

OSB is heavy, but not that much more for a Teardrop. I used it in my mobile home, my woodshop and my shed. If it is protected on the bottom, I do not see where it would be an issue at all for use on the floor. I will be using it for my next camper build as well, I like that there are no voids, and I will be using the roof repair/sound deadener that comes on a roll from the box store to protect the underside.

[Lgboro]

At the price of gas / diesel the extra weight might come to matter at some point. The floor on a torsion box tear only supports your weight or what is loaded on it - the walls support the roof and majority of the weight so although more solid may be unnecessary. My build has biscuit joined 1/2 inch cedar sandwich with two layers of blue styro insulation.

[mikeschn]

So what's a tear builder to do? My suggestion is to buy the nore expensive marine grade plywood. It has inctedible strength, and is made from very high quality wood. The sheets are nearly always flat and without warping. Well worth the extra cost

What your thought on the dryply from Home Depot?

see here: http://www.homedepot.com/h_d1/N-5yc1v/R ... reId=10051

Mike...

[Verna]

What your thought on the dryply from Home Depot?

see here: http://www.homedepot.com/h_d1/N-5yc1v/R ... reId=10051

Mike...

Mike, this is the plywood I used as the subfloor in my bathroom when I gutted it. I do not recall seeing any voids. I liked the water-resistant qualities, and hope it does live up to its advertisements. I also used left-over pieces for a "casket" for my last dog. There's no sinking of the ground where I buried her, but someone mentioned that the lack of oxygen would slow any deterioration of the plywood.

And, another observation about it--I left a couple of 10"x8' strips laying on the concrete garage floor for about a year. It did not warp....more than I can say for some "normal" plywood that was laying next to it.

[Dale M.]

So what's a tear builder to do? My suggestion is to buy the nore expensive marine grade plywood. It has inctedible strength, and is made from very high quality wood. The sheets are nearly always flat and without warping. Well worth the extra cost

What your thought on the dryply from Home Depot?

see here: http://www.homedepot.com/h_d1/N-5yc1v/R ... reId=10051

Mike...

Got to wonder though..... Written specs. Says it NOT tongue & groove, but picture....

Also does this mean depth of tongue or groove...

Assembled Depth (in.) : 0.703 in

And then there is no "end" T&G for length only seems to have T&G for width...

Also says its 23/32" (almost 3/4") thick but specs state .47" which would be 15/32 (almost 1/2")...

So many questions....

Dale

[Verna]

What I used for the bathroom floor was T & G. It was so much easier to "join" pieces than the T & G OSB that I've used on the Habitat for Humanity builds.