Sagging floors under toilets don’t always require replacing rotted wood.
I’ve repaired a bunch of floors where the toilets had been leaking for some time.
In most cases, the leak had been going on for so long that some of the floor had started to rot.
In these cases, the rotted wood has to be removed first. After that, in the worst cases, the wood has to be replaced. If your lucky and the damage isn’t too severe, you can just scrape away the top layer of rotted stuff and use a floor leveling compound the smooth out the area.
The thing to be concerned about is whether there is enough good wood left so you can make sure the toilet flange can be screwed down and held tightly in place.
The toilet has to be anchored securely. If the toilet later starts to “rock” because the flange is loose, your troubles will start all over.
In most, but not all cases, you will want to install a layer of “underlayment” over the whole floor to help insure a smooth surface throughout.
If the leak hasn’t been going on for too long, the wood may not have to be repaired.
Sometimes, the wood hasn’t started to rot yet and has only gotten soft enough to allow the toilet to sink a little into the floor. Again, in these cases, a little floor leveling compound is all that is needed.
My most recent case was precipitated when a replaced water supply line had not been tightened enough and water soaked the wood (Particle Board) floor enough to make it start to lose it’s strength. The weight of a person sitting on the toilet, then caused the floor to sag.
It only took 2-3 days for this “sinking” to take place.
It was in a 2nd bath in my own home so I procrastinated several months before getting around to fixing it.
As it turned out, the waiting time allowed the particle board flooring to dry out completely.
I thought I was going to have to add some bracing and replace some of the particle board. That would of meant adding 2x4s and fitting two individual pieces of particle board – one on each side of the toilet flange – so they would continue to support the flange and toilet.
When I went to bust out the “rotted wood”, I found that the strength of the particle board had not been affected. After “drying out
completely”, it was still so strong that I couldn’t even bust it with a hammer.
This stuff starts setting up in about 5 minutes so, you have to work fast and don’t mix too much. Because it sets so fast, you can easily mix more when you need it.
I mixed probably 5 -6 small batches so I could get it placed as I needed it in position, making sure to get enough under the flange to support itself when done.
Work with small batches.
This allows you to manipulate the leveling paste into, around, and under the flange as needed, making sure to keep it low enough that your final coat(s) can be level with your finished old floor.(Your new floor will go right over this.)
The 1st batches were made about the thickness of peanut butter. The final coats are more like mayonnaise to make it easy to manipulate and level out.
I did have plenty of good wood under all this, so I was able to tighten the toilet flange securely in place.
Use the chisel to start the old nails lifting upword.
This job took me a total of about 4 hours, and cost a total of $55.00 (With the new vinyl and floor molding.)
Normally, one can’t wait months for the floor to dry out and get hard again. In that case, you’d have to replace some of the particle board and probably put in some bracing to hold the new smaller pieces. You couldn’t just cut a piece of flooring to go over and around the flange because the flange has to set on top of the floor in order to be supported. Add a couple hours if you need to do that.
(This was in a mobil home – Most regular houses are built with double layered floors so replacing the top layer is usually all that is needed. But then again, sometimes……)
Update – it’s been 4 years and it’s holding up nicely.
What would you have done? Enter your comments below!