Tile underlayment problem...help!

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Topic by Dr_Unix posted 05-17-2009 07:06 PM 7932 views 0 times favorited 5 replies Add to Favorites Watch
View Dr_Unix's profile


5 posts in 5124 days

05-17-2009 07:06 PM

Topic tags/keywords: foyer floors doors stairs foundation tiles concrete remodeling flooring

Here is my problem, I’ve got a 4” (?) thick concrete sill that runs through the center of my foyer. It was the threshold for where the front door used to be. The previous owner poured a self leveling cement slab before laying tiles. Since the sill and wood move at different rates eventually the underlayment cracked and disintegrated. Check out the picture for a better visual:

On either side of the concrete is plywood (3/4” I think) decking. Plus I have the stairs and doorway to contend with, So I can’t lay a deep layer of mud.

What I would like to do is put radiant heating in the floor because it’s really cold in this entryway. Does anyone have any ideas? Should I get a jackhammer and remove the sill?

Thanks for the help.

View aaronmolloy's profile


1 post in 5123 days

05-17-2009 09:37 PM

If the two sections of floor are at different height would it be possible to apply some plywood to the other floor

View BeachedBones's profile


36 posts in 5222 days

05-18-2009 03:41 AM

I would build up both sides with plywood and lay a continuous underlayment across and over the concrete sill to tie it all together. I’ve heard of people laying down radiant piping then pouring a layer of cement over the whole area to level it out. I’m not sure what requirements the structure would need to handle the weight.

Both scenarios would probably mean that you’d have to trim or re-hang the doors to clear a higher floor level.

View PaBull's profile


694 posts in 5480 days

05-22-2009 06:13 AM

You can rent a grinder to take it down, check out the local rental yard and see what tools they have for this. When you do this, be sure you seal off this section of the house to keep the dust to a minimum.

Good luck.

View ahock's profile


4 posts in 5115 days

05-26-2009 04:29 AM

With the space limitations, you could go with an electric radiant flooring and the Shluter membrane. You need to bring the surfaces even though first. Chip out all the old self-leveler, clean it up really well. Get some new self-leveler and an additive to help it stick to the concrete; it’s not bad to etch the concrete first with some muratic acid. Once you have the floor level, you can set the Shluter membrane in thinset and let it harden overnight. You’ll need a 1/4” of thinset over the top of the membrane to shield it from the radiant heating, so add a 1/4” of thinset. Then you can lay the electric radiant in another 1/4” of thinset. Let it set overnight and then lay your tile. You’re going to be adding roughly 1” to 1 1/4” to the highest point in the area this way, but it’s the lowest combination I can think of.

Good luck!

View frivs's profile


5 posts in 2042 days

11-02-2017 04:26 PM

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