Hole repair + new underlayment. Help needed.

tomeczekj · 04-19-2012, 07:40 AM

Hi, I'm hoping somebody here can help me out by telling me what I need to buy and how I can go about fixing this disaster?

Photo:

I will be laying porcelain tile in this bathroom.

How would I go about patching up this hole? Should I reinforce the area with 2x4's to support the toilet/PVC?

After the hole is patched up and ready for a new underlayment/foundation, should I remove the old ply or install overtop of it?

What type of board should I use? A friend of mine recommended "wonderboard".

After I lay my "whatever board" down, I can simply screw it to the joints and begin grouting/tiling?

Will the rotted out/possibly moldy wood around the toilet PVC be a problem?

Thanks!

TarheelTerp · 04-19-2012, 08:22 AM

This is far (far!) from a disaster.

1) remove more plywood (especially the wet part) and try to do that so your edges align with the joists.
(don't be obsessive though as you can always add a 'nailer' block where needed)
2) finish the plumbing work.
3) replace that missing/rotten plywood with good clean fresh plywood (of same thickness) to close up the floor.

As for what your finished floor requires under it... start with the finish material choice and work down.
Then install those things. If the plan is for tile then hire a tile guy and step back.

tomeczekj · 04-19-2012, 09:03 AM

Thanks for your reply!

If I replace my ply, isn't there a good chance my tile guy will want to remove it and put down some sort of cement board?

TarheelTerp · 04-19-2012, 11:14 AM

Quote:

Originally Posted by tomeczekj

If I replace my ply, isn't there a good chance my tile guy will want to remove it...

nope. more like a slim to none chance.

Quote:

and put down some sort of cement board?

yes; they'll want to put a good bed down for the tile.
but that won't mean removing the plywood.

tomeczekj · 04-19-2012, 11:49 AM

Should I remove all of the plywood and replace it with perhaps a thicker/higher quality ply? Or only replace the water-damaged ply?

JazMan · 04-19-2012, 12:04 PM

I recommend you do steps 1, 2 & 3 of what tarheel said. But because you'll likely have several small pieces, and since they will not be t&g, you need to install an underlayment grade plywood that is at least 3/8", preferably 1/2", then your concrete backer into thinset mortar etc. then the tiles.

Jaz

Marko6820 · 04-26-2012, 01:26 AM

Tom,These guys are wright, but maby not making it easy to under stand. Where your toilet is to go, you need to remove the rest of the plywood board that is under the toilet to the seams. Looks as if it is aprox 4' X 4' take it out to the joints, & install a new piece of the same thickness. Then your cement board is layed on top of your plywood. none of your plywood will have to be removed to lay the tile after this fix. It is not ness to replace all the ply wood. If done right , your backer board will stiffen your floor to support the new tile. Good luck! Marko

12penny · 04-26-2012, 06:50 AM

Quote:

Originally Posted by Marko6820

Tom,These guys are wright, but maby not making it easy to under stand. Where your toilet is to go, you need to remove the rest of the plywood board that is under the toilet to the seams. Looks as if it is aprox 4' X 4' take it out to the joints, & install a new piece of the same thickness. Then your cement board is layed on top of your plywood. none of your plywood will have to be removed to lay the tile after this fix. It is not ness to replace all the ply wood. If done right , your backer board will stiffen your floor to support the new tile. Good luck! Marko

Wrong...backerboard adds nothing structural. Do as Jazman suggested. Fix the hole, add 1/2" underlayment grade plywood, then backerboard set in thinset.