# Ditra on slighty uneven subfloor



## oh'mike (Sep 18, 2009)

You have a problem--The easy fix is to remove your patch and figure out why there is a height difference.

I'll bet your patch wood is thicker than the old floor. Is removing the entire subfloor in that room an option?


Filling a low spot is easy enough--Leveling a high spot is NOT.

Don't use firmset as a leveler for an area that size--the finished work will be like a roller coaster.

Doubling your membrane as a leveler (at $1.80 per sf) is a funky fudge job--

You want this right--start with a flat floor. Good luck-have fun--Mike--


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## CoryStemp (Jan 25, 2010)

i was thinking of replacing the entire subfloor but i can only get a skill saw so close the the walls. how would i go about cutting the rest out right up against the wall. could i use a sawzall? If so, how do i keep from cutting too deep into my floor joist.


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## oh'mike (Sep 18, 2009)

The new subfloor will be thicker than the old one.--The low spots can be filled with firmset when you tile or set your membrane.

You can make safe shallow cuts with your sawsall by putting the blade in UP SIDE DOWN-use a long blade and you can make shallow cuts without nicking the joists. Screw blocking to old subfloor-to support the new.

Remember--it's easy to fill a low spot! High spots are your enemy--HaHa---mike


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## YesMaam27577 (Jan 16, 2010)

If the difference is truly 1/4", then cut some pieces of 1/4" underlayment to be added to those low spots.

Beats the heck out of puling up the entire floor!


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## YesMaam27577 (Jan 16, 2010)

Forgot to add.......

And if its just a bit more than 1/4", use 1/4" ply and some builders felt as shims -- double or triple layers as needed to make up the difference.


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## Bud Cline (Mar 12, 2006)

Remove the patch and do it again using the proper material thickness this time. All those other cement type patches will only cause issues down the road when things try to expand and contract and crumble down below.


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