Just removed old linoleum from bathroom floor and discovered the plywood underneath has rotted near bath tub?

Question

I am renovating my bathroom and have just removed 18 year old linoleum from the floor. I'm putting in new porcelain tile and a concrete backer board. However, I just discovered that the ply-wood underneath the old linoleum has rotted near bathtub and toilet. Should I or can I replace the plywood or should I just fill in some of the rotted parts with a concrete patch up mixture. What is most likely to be underneath the ply-wood? I'm wary about lifting it up to check. I want to make sure the new tile has an even floor so variations in pressure doesn't crack the tile and that the bathroom is clean and safe. Any advice is appreciated!

Answer 1

I'm assuming your house is a pier and beam structure or else your project is on the 2nd floor.  If so, it would be wise to make sure that there isn't any further damage to the floor joists.  If it appears that the plywood decking shows signs of long term damage, it may have affected the joists as well.  Those will have to be repaired and can be spliced instead of replacing the entire joist.  Since we're talking about a "wet area" and bathrooms are typically considered a wet area, I would suggest a cement board (Hardiback) and then s***w it down onto the floor joists with screws about every 8 to 10 inches apart.  Once down, you can apply whatever floor covering you wish to lay down.

Answer 2

your bathroom renovation cost just went up but not by much, yes you have to tear out the old plywood under the toilet and tub as well and you may have to add nailers to the floor joists if they are too badly rotted as well . if you don't the floor will be spongy and your tile will just break out, your toilet will start to move if it hasen't all ready , so spend the extra time and do it right or you will do it twice  

Answer 3

Have an expert come to check out the wood. You must know somebody who knows a remodeling contractor? I am in the bath remodeling industry and many people have had water go behind their walls and under their tubs. Whether or not there was lots of water or a little is the issue.

Don't cause yourself extra work or money.  Don't guess.  Call in an expert.

Many times you can just allow the wood to dry, even with a fan for a couple of days, and put a new piece of plywood over the space the same size as the tub or the old opening.  We do this in many cases.

Answer 4

Once rot has started it needs to be removed or it will continue.  I would suggest removing the rotten peice of plywood and replacing it with a humidity resistant sub-floor product such as Adventech.  It's similar to regular OSB plywood in appearance, but will hold up better in a wet enviroment such as your bathroom.

Answer 5

Remove the bad plywood. The subfloor may also need replacement and do this if it is needed.  Merely covering it over is asking for trouble.  Rebuild what is worn.

Answer 6

To do it right, you need to remove any rotten wood, and there's probably more than you can see. Covering it up will just mean tearing up your new floor when things start to fall through it, which they will eventually, and covering up damp areas will just accelerate the process. Just as important, you need to find out why that plywood is wet and fix the cause of it or any new wood you put down will have the same thing happen to it. If you just cover it up, you will walk around for the next few years knowing all that dampness is down there, wondering how bad it'll be later and you know it will be worse the next time you look at it. Fixing it properly will give you that nice warm secure feeling that you fixed it right and it'll be good for years.