'sub' floor....

[mrcaptainbob]

Part of this bathroom rehab project is to remove/repair/replace some of the joists wasted from years of water damage. Will be stripping the entire room to the joists....about an 8x10 area. Presently the joists are 8/4 x 7 3/4 on mostly 16" centers. The sub floor boards are t&G 3/4 x 5 positioned perpendicular to the joists. 3/4 ply was placed over that and had vinyl glued to it. Is it okay to lay 3/4 CD on the joists and cover that with another 3/4 layer of maybe BC? Then another layer of smooth (luan)?We intend to finish with vinyl and about four smallish rugs...

[floorman]

Unless there are heighth issues to bring this floor back up to meet something then just 1 layer of 3/4 is fine and then a multiply or sure floor panel.Most manufacturers do not gaurantee their product over luan anymore.Bc would probably be better as the one side is already sanded[8D]

Floorman
floorlayers union local 1310

[mrcaptainbob]

Thanks, Floorman. You're right about the height issue. The original was 3/4 t&g covered with 3/4 ply. So I'll just lay down two layers of that and will make sure to stagger the joints. I have a question about that luan as underlayment. What is it that the floor covering manufacturers are concerned about? I want to follow as correct a path as I can after all this work....

[floorman]

What happens is that the mahogany finish on the good side of the sheet will sometimes delaminate and cause failure,i don't know why it will on that stuff and not the others.
Hold on, i stand corrected i just looked it up in the new reference manual from armstrong it does say you can use luan but it has to be type 1(exterior),it goes on to say that underlaymenst are classed as luan but they are not and may cause problems of discoloration,indentation,loss of bond,and delamination when used as underlayment.
So there you have it from the 2004/2005 Armstrong manual,learn something new everyday in this biz![8D]

Floorman
floorlayers union local 1310

[mrcaptainbob]

And us wannbee's are learning from you good guys. Thanks for that info, FloorMan. Will check to see if what I purchased is the 'good' stuff. That's why I got concerned.....I already bought the stuff when I read your post....strange that the luan would delaminate and the 'regular' ply wouldn't. Except for interior/exterior/marine application, I would've thought they'd use pretty much the same bonding agent. As somebody famouse recently said....'ya learn somethin' new every day'!!! Thanks again for the help.