Need advice on shimming uneven floor
conrj967
| Posted in Construction Techniques on
I will be putting down some 3/8″ plywood on our dining room floor in preparation for the installation of sheet resilient flooring. Because the floor is uneven, it will be necessary to do some shimming under the plywood or to use leveling compound on top of the plywood. In some places it will require 1/4″ of shims.
Is it acceptable practice to do this shimming with asphaltic roofing felt or would it be better to screw the plywood down to the uneven floor and use leveling compound on top of the plywood?
Is the asphaltic felt incompressible enough?
Are there any limits on the total shim thickness of the asphaltic felt?
Any help would be appreciated.
Ralph
Replies
I'm going to ignore all yuor Qs, pal, sorry, BUT I'm going to pick up on the 3/8" ply - Don't use std ply. Buy special u-lay, whether it's a dense sort of OSB, or special u-lay plywood....std plywood has voids in the internal plies you cannot see, and can collapse, leaving depressions in your nice floor.
ciao for niao
To those who know - this may be obvious. To those who don't - I hope I've helped.
I'll second the recommendation to use underlayment. Not only is is smooth and solid, but the edges are coated with a wax to prevent rubbing that can make sqeaks in your floor.
I would do the shimming with floor levelor UNDER the underlayment first, then a minor tougchup over it if still neccessary
Welcome to the
Taunton University of Knowledge FHB Campus at Breaktime.
where ...
Excellence is its own reward!
I don't like the thought of putting anything remotely compressable under a floor for shims. I'd be interested in hearing how you will get the new floor within 1/4" of level---as well as why a vinyl floor needs to be that level.
I appreciate your recommendations. I was planning to use BCX grade plywood which I understand is recommended by the Resilient Flooring Institute, but I will investigate "underlayment".A further explanation of the problem: The joists are 2 x 10's. The sub-floor fastened to the joists is made up of 1 x 10's oriented diagonally. On the sub-floor is a single layer of tar paper, then 5/8" plywood. I am replacing a portion of the 5/8" plywood with 3/8" to take a crown out of the dining room floor. (I have also planed the most offending joist down too, but that does not solve the problem entirely.) I am not trying to make the floor level. It will still be about 3/4" off level when I'm done, but want to get it relatively flat to avoid having to change shims under the dining room table every time leaves are added or removed and so all four legs of the chairs are in contact with the floor. I don't believe I can use leveler under the underlayment or plywood because there are 3/16" to 1/2" gaps between the sub-floor boards.Ralph
When shimming to flatten floors, I don't use felt, I use shingle scrap. Can't rot; won't compress; and it's cheap as you can get. What more could you ask?
I figure a shingle is 1/8" thick, or close enough so as not to matter. So two scraps stacked will give you that quarter inch you're talking about.
Tack the shims in place with an HT-65.
Dinosaur
A day may come when the courage of men fails,when we forsake our friends and break all bonds of fellowship...
But it is not this day.
If you're using sheet flooring, you could just fasten the plywood to the joists without shimming and use a floor leveling compound or self-leveling cement on top.
Billy
No need to "investigate" undelayment grade plywood. Just read the stamp on the ply. Among other thiungs, it will say "Underlayment grade" or similar if it is suitable for underlayment use.
I'm sorry, I thought you wanted it done the right way.