Is there any disavantage to using 3/4" pressure treated plywood on the floor besides the higher cost? Any trouble painting it to be seen in the cargo bay? Thanks Ray
Hi Ray,
You may want to reconcider using Preasure Treated lumber within closed quarters,
The chemicals are pretty strong that are used to treat it. I belive some are toxic too.
Nick-
Hi Ray,
What Nick said and the new chemicals used in pressure treating are very corrosive, or so I am told.
Note the new specially coated screws they have you use.
I replaced several pieces of my floor and the worst were over the rear wheel wells.
I just painted them with two heavy coats(bottom and sides) after I cut to fit and they look nice.
I also used a layer of tar paper(over metal pieces in well) as a backup for any wicking that might occur.
YMMV
Cliff
I used 3/4 PT plywood over wheel area and used Standard 3/4 plywood on the rest of it.... with no issues. When I ripped the old floor out it was real rotten over the wheel area, it was all painted both sides from the factory.
Ron
Unless they have changed the formula, Pressure treated may contain high levels of arsenic or other poisons. It is usually
also water-logged in most versions. Gloves and Respirator are recommended on the labels....
If you need to protect plywood, Use something like coppertox which uses copper sulfate and paint with an epoxy paint.
the only other reason would be to keep carpenter ants from taking up residence...
I doubt that a bad termite problem would exist in a bus that would warrant pressure treated.
Use Marine grade if you are worried about lasting a long time. Pay more to get more....
Thanks Guys, good info. Don't need toxic fumes! I was just looking to put down my floor & the bus is under tarps which leak & I didn't want puddles on my new floor to delaminate. maybe I can paint the topside and later when the bus is sealed I could sand with a belt sander so the oak boards will stick?? Thanks Ray
If water is the concern, why not use exterior grade plywood, like they sheet roofs with. It isn't pressure treated and doesn't send off toxic fumes. Cary
The treatment was changed last year and is, to the best of my knowledge no longer toxic. The treatment is no longer green either.
Richard
Quote from: Cary on March 31, 2007, 10:50:40 PM
If water is the concern, why not use exterior grade plywood, like they sheet roofs with. It isn't pressure treated and doesn't send off toxic fumes. Cary
I recently bought a sheet of 3/4" roofing / flooring grade plywood (with all the correct stamps on it), and was really disappointed by how poor quality it was. My first choice for plywood would always be multi-lam Russian birch - a very very good product and good value for money, but not available in 8' x 4' sheets unfortunately. True marine-spec ply (BS1088 - not sure if there's an American equivalent) is hellishly expensive and there is no way I could justify using it in the bus.
For those who have mentioned rotting floors above the wheelwells, one possibility would be to use bitumen-coated ply with the coated face downwards. I've never used it myself, and I suspect the basic wood isn't very special, but I presume that it is very waterproof.
Jeremy
The last step i would do after all my painting etc, would be to spray a good heavy layer of a rubberized undercoating on the bottom of the wood. This stuff stays fexible and should not only help waterproof but could help with sound proofing as well. I have used 3M and it is a great product and have also heard good things about NAPA's version.
Thanks again for the ideas. On the floor rotting over the wheels I have already done something I hope will help. I had purchased two 5 gallon part (A) & part (B) pour foam and dumped it over all 4 wheel covers. It had fiberglass insulation in the floor that held moisture and rusted the metal skins over the fiberglass wheel wells. I had repaired the metal, painted the entire w/well area with por-15, and poured pour foam in it then cut the foam down to the floor surface and is now waiting for plywood. The foam was for marine floatation in the bilge for boats, I bought from e-bay. I recently bought another 10 gallons from the same person to pour in places before I get a sprayfoam job on the walls and overhead.
Ray
AC (grade) Ply is a good option it has one side that is smooth which makes a nice underlayment for flooring etc.. If any of the C side is exposed to the underside elements you could coat that with an epoxy or similar coating. OSB is another good option as it does not delaminate like ply.
RE: OSB is another good option as it does not delaminate like ply. It may not delaminate, but it swells & looses strength when moisture gets in. It is not stable enough to lay hard wood or tile over it (- according to the manufacturers).
As for coating the new wood, the wooden boat restorers use a 'Clear Penetrating Epoxy Sealer' to enhance the life of the wood. I read about this stuff in Don Danenberg's 'How to Restore Your Wooden Runabout'. It has been out since 1972 & has a proven history of almost doubling the life of the paint job when it is used.
If it's good enough for boats that are worth more than a new bus . . . .
The top coat of rubberized undercoating is a GREAT idea!
Hi Ray and All
I Looked into pour foam but the cost was to great in 1/2 gallon kits. Could you tell me the cost in the 5 gallon cans. I also need the Name, address and phone number of the person that you got it from. What bus are you filling with the pour foam and how much will it take.
I have cut the 3/4 plywood the same size as it came from the factory. To do this I had to go to a Riemeier lumber Co. here in the City to find 4 x 10ft AB plywood. The lumber has been painted with three coats, cut to size an set in place. The 4 x 8 ft BC plywood came from the big box store, painted the same way. The 4 x 8 will not lay flat on the floor, the 4 x 10 will. I just have it sitting there till we insulate under it. You get what you pay for.
Paul
www.incredibus.com
OSB can absolutely be used as a subfloor for hardwood and tile. OSB or Ply exposed to moisture will cause problems. If you are going to use OSB they make a grade for exterior use.
www.osbguide.com/pdfs/SSflr.pdf (http://www.osbguide.com/pdfs/SSflr.pdf)
Quote from: kyle4501 on April 11, 2007, 06:27:59 PM
RE: OSB is another good option as it does not delaminate like ply. It may not delaminate, but it swells & looses strength when moisture gets in. It is not stable enough to lay hard wood or tile over it (- according to the manufacturers).
As for coating the new wood, the wooden boat restorers use a 'Clear Penetrating Epoxy Sealer' to enhance the life of the wood. I read about this stuff in Don Danenberg's 'How to Restore Your Wooden Runabout'. It has been out since 1972 & has a proven history of almost doubling the life of the paint job when it is used.
If it's good enough for boats that are worth more than a new bus . . . .
The top coat of rubberized undercoating is a GREAT idea!
I agree that OSB isn't suitable.
I have used the epoxy sealer stuff (SP Eposeal 300 is the brand I've used), and although it's very good it seems very expensive for what it is - I may be wrong, but it just seems to be regular epoxy thinned down with lots of solvent. If I went that route again I would look into making my own.
There is a very good single pack product called 'Universal Clear Primer', which I have known boatbuilders to use before applying any other kind or coating material (or even bonding material, which always seems a bit odd to me). UCP gives off some very interesting fumes, so use it in a well ventilated area!
Jeremy
Quote from: buddydawg on April 12, 2007, 05:13:22 AM
OSB can absolutely be used as a subfloor for hardwood and tile. OSB or Ply exposed to moisture will cause problems. If you are going to use OSB they make a grade for exterior use.
www.osbguide.com/pdfs/SSflr.pdf (http://www.osbguide.com/pdfs/SSflr.pdf)
I know what the OSB manufacturers say about their 'miracle' product. I have also looked in to what contractors & suppliers of finish materials have to say about it.
I have heard the squeeks in hard wood floors laid over it & seen the cracks & poped tiles that have been laid over it. The local flooring contractors that I have talked to about this stuff have all used it & will not warranty any hardwood or tile installed over it. The OSB manufacturer won't either.
My personal experience is that it moves around a LOT. If you don't leave the propper end gap, it will cause problems. If you don't seal the cut ends, it will swell faster at the cut end. The problem is that when (not if) the wood swells form moisture, the glue to wood bond is weakened & eventually broken. Once this happens, all you are left with is a bunch of small chips of wood. When this happens with plywood, you at least have larger pieces of wood left.
YMMV
FWIW - My sign painter fills any voids, sands, uses Acrylic primer on BC or better plywood (full sheet) including the edges (multiple applications), Acrylic base color coat, then applies this stuff;
http://www.epoxysystems.com/acrylic.htm
I have a sign put up in 1997 that's been out in the Fla sun and rain for those ten years (never been cleaned and posts replaced 3 or 4 times due to termites and rot) and other than a little algae and dirt it looks like it could go another 10 years.
I would suggest putting felt paper on the steel members only to prevent chafing.
this may be overkill though ;-)
Well Poop!
I just started replacing and dropping my floor a few weeks back and used, you guessed it, 1/2" OSB.
The first thing I did was to put multiple coats of Thompsons Water Seal on it and let it soak in for a week or two. My next step was to use Thompsons on all sides of sheets of luaun. I then clamped the sheets together with lots of 5 gallon busckets full of water to press the sheets together.
That was at the end of February. Since that time, we have moved a little over 80 miles and have already noticed swelling and uneveness. It looks as if when we get settled I'll have to replace that part I've already done.
That sux, with a great big X!
This time I'm going to use 1/2" BC and put a sheet of sealed luaun over that.
Luckily, It's only a 6' section, so I won't have that much to replace!
Dallas
For flooring applications wheter using Ply or OSB you should use 3/4" for strength. Luaun should not be used as and underlayment especially for wood and tile.
I did a little looking (little being the key word) on the net & found this:
http://www.umass.edu/bmatwt/publications/articles/osb_vs_plywood.html
It seems to be a well ballanced article concerning the OSB vs plywood debate. The main problem for OSB is the moisture issue (retains water longer inducing rot, & the swelling issue) & it isn't recommended for use in certain areas because of this.
I feel that it is too easy for a bus to have the potential of a high humidity environment for OSB to be suitable. But OSB is a good choice for the bus barn! ;D
Many years ago I worked for three years at Georgia Pacific particle board plant. I was an instrument tech. Anyways I used to hang out in the lab and watch the lab techs run tests each shift. They would soak it in water and it had to asorb no more than a given volume of water. They also pushed a steel ball through it and measures the force, and they would pull out a screw and measure this also. It was all interesting but bottem line it was saw dust and elmers glue by the 18 wheeler load. Sweeling and delamation was the biggest returns especially from the moble home builders. To heavy anyways.
Ray