How to fill in holes before building thin subfloor

bighak

I bought a 1962 house with pink tiles everywhere. I removed them. Under that I found a 3/4 plywood sheet covered in thinset mortar. I ripped that out. Under that I found the badly damaged original hardwood flooring and some areas with plywood (kitchen,etc).

My plan is to put a 1/4 thin plywood subfloor over this original flooring and then put in engineered wood flooring.

The issue i have is that there is many spots where the original hardwood is badly damaged or missing a piece.



So my question is what should I use to fill these holes? Latex leveler?

Also is 1/4 plywood too thin considering there will be solid hardwood and plywood under it to provide firmness? I think I want to staple the engineered wood flooring. Will the staple be able to go thru the 1/4 plywood and then penetrate correctly the hardwood under?

rusty baker

I would not use 1/4" ply over that floor. It won't add much to strength.

__________________
"I'm twisted, not sick. Sick implies, I'll get better"
Semi-Retired Installer
Installing since 1973

joecaption

Clean the low areas out and use plywood the same thickness as the flooring.
Going to need at least 3/8" subfloor rated plywood. 1/4" would just follow the cupping and flaws in the floor.

Seattle2k

Pull out the old hardwood floor. You may even be able to find a salvager who will do the work and haul it away for free.

rusty baker

I would fill the holes with 3/4" ply and then sheet over the whole thing with 1/2"

__________________
"I'm twisted, not sick. Sick implies, I'll get better"
Semi-Retired Installer
Installing since 1973

brucem609

Depending on the quality of the rest of the flooring would be my first question. But going on the assumption tha the rest is fine,,otherwise you would have said something-here goes.
1st choice rip up all old boards, make sure all joists are good condition,Cover in 3/4" plywood add in flooring
2nd choice fill in empty gaps with appropriate thickness plywood, cover with 1/2" plywood add in flooring

Of course before adding in your flooring clean all loose debris and make sure any existing is sound.

If it was my house get rid of the old and start fresh

GOOD LUCK