Flooring Tile - Kitchen Tile underlaymnet

All,
My wife decided she wants tile in the kitchen/breakfast area, currently vinyl. the vinyl is attached to particleboard which is attached to the subfloor. I am in the process of removing the particleboard and replacing with 5/8" plywood. So far in the project I have just used 5/8" sheathing plywood, not AC or BC. After reading the sticky, I am concerned that the sheathing is not the proper type plywood. Of course, on top of the plywood, I will be installing backerboard.

Is standard plywood sheathing suitable for this installation?

Thanks,
Kevin

Kevin, you could have probably spend less money and got Advantech, a tongue and groove subflooring material in 3/4", made for what you are doing. I had to do what you are doing this week, but I had to match tile height from a living room to a hallway, but refused to install it on the particle board. Had to remove the particle board (luckily there was 3/4" plank subflooring. I had to build back up to the original grade, so I had to use 1/2" plywood and 1/4" cbu. Luckily the plywood was only 15/32", so my grade was right on.

chandler,
Thanks for the input, but I am replacing the 5/8" particleboard with 5/8" plywood so that I can match the hardwood height in the adjoining rooms. When I installed the hardwoods I had to replace particleboard there as well but I used BC plywood and due to cost I was trying to use plywood sheathing instead of BC.

Kevin,

Does your ply have anything stamped on it?

The reason we say exterior grade ac/bc is because the ply has glue that can take some moisture and not warp. You should be ok with what you have though if it's not full of knots.

HotinOKC,
Thanks for the insight. You recently provided me with excellent advice when I was installing bamboo flooring in which I laid down BC plywood before installing the floor. In the interst of budgeting, I assumed sheathing would be okay since it used for exterior/interior purposes. It does have something stamped on it, I just don't know what right now. Pretty sure it is Georgia pacific brand, and I know it 19/32" sheathing approx $13 a sheet at lowes. There are definitely more knots in it than in the BC. What problems do the knots cause?

Thanks,
Kevin

You should be alright Kevin. Is this the second layer of plywood?

Is sheathing grade plywood the right thing for an underlayment? NO. Will it work? Probably. Should you remove it and install the right thing? You should, but, I know you won't and I probably wouldn't either if I had made the same mistake.

What's the difference between sheathing and underlayment grade? The quality of the wood, AND the underlayment does NOT have voids in the inner plies. Sheathing can have voids, besides those knots. You are not supposed to walk or place weight on sheathing, obviously. :coffee:

The $$$ factor is why we have so much bad work out there. But, it's one thing when you go for the cheapest product for your own house. We see this all the time from contractors who know better but don't care so they can keep the price down. I see this all the time.

Just this week I went to do an estimate for a backsplash and powder room floor. The kitchen was all torn up for a complete remod. They are going with hardwood in the kitchen. The base cabinets were almost all in. They found particle board and the client's (an attorney) contractor went to HD or Lowes and bought sheathing. I spotted it as soon as I walk in, all the knots etc. Not only that, but there were not enough fasteners and the sheets were butted. YIKES :wall:

The client almost wished I haven't said a word about it. You see he said the contractor is "like a son". He had represented the contractor a few times while being sued for bad work I guess? Never mind........... and I didn't get the "promised" call the next day either. It doesn't pay to tell the truth I guess? :wall:

Jaz