[jep]

I had a plumbing leak that we discovered at the end of February. The leak soaked my subfloor which turned out to be 3/4" particle board with 1/2" OSB on top which was covered with linoleum. This was in a utility room with a washer and dryer, toilet and sink. I'm planning on putting down Hardibacker and porcelain tile. I have replaced the particle board with 3/4" plywood and am wondering if I can skip the second 1/2" layer of subfloor and put 1/4" Hardibacker and 16" x 16" tile directly over the plywood? The tile are about 1/4" thick. This will bring the floor level back pretty close to what it was before. Are there any downsides to not having the 1/2" layer on top of the 3/4" plywood?

 

[de-nagorg]

Only one.

The toilet flange needs to be supported fully, otherwise you "rock the pot" while using it, which will eventually leak, and you will be back repairing it.

More expensive then, because you will need more tile.


ED

 

[Nealtw]

I had a plumbing leak that we discovered at the end of February. The leak soaked my subfloor which turned out to be 3/4" particle board with 1/2" OSB on top which was covered with linoleum. This was in a utility room with a washer and dryer, toilet and sink. I'm planning on putting down Hardibacker and porcelain tile. I have replaced the particle board with 3/4" plywood and am wondering if I can skip the second 1/2" layer of subfloor and put 1/4" Hardibacker and 16" x 16" tile directly over the plywood? The tile are about 1/4" thick. This will bring the floor level back pretty close to what it was before. Are there any downsides to not having the 1/2" layer on top of the 3/4" plywood?

The plywood is fine the question is more now about the floor joist height and length between bearing points and how far apart.

 

[jep]

The 2x12 joists run about 7 1/2 feet from support to support. They're about 2' apart.

 

[jep]

Planning on putting the flange fully on the tile.

 

[Nealtw]

The 2x12 joists run about 7 1/2 feet from support to support. They're about 2' apart.

24" on center might be a bit to worry about, wait for the tile guys to show up.

 

[ron45]

The sub floor and underlayment should total at least 1-1/4" thick.

I would go with 1-1/2" thick just because people are bigger now-a-days.

 

[HotRodx10]

With joists at 2' o.c., you'll want at least 1 1/8" T&G OSB for supporting porcelain tile. It's 3 about times stiffer than 3/4" OSB, and for porcelain tile, you need it very stiff, because the tile is very rigid and brittle.