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Fixing my Durock Mistake

9K views 12 replies 5 participants last post by  oh'mike 
#1 · (Edited)
Hello. Last weekend I started my tile project, of prepping my front porch for tile. (I framed porch with 2x10" joists, 16" OC with a run of 6'). I have 3/4" plywood ontop of that.

Ontop of the plywood I installed 1/2" Durock, and here is the mistake I made...I liquid nailed it down instead of using thinset and screwed the cement board 8" OC with 1 5/8" square heads. I thought it would be OK to use liquid nails instead of thinset, until I started reading the forums...which I should have done prior to starting this.

I really do not want to tear off the Durock, as I doubt it will be reusable. I was thinking since I will have to buy more Durock either way, can I just apply thinset ontop of the Durock I laid incorrectly, and add second layer of 1/2" Durock ontop of the thinset (screwing this second layer as well)? Will that eliminate any moving that may occur because of the gapping caused by the liquid nails?

I realize 1" of Durock doesn't add anything structurally, but I am hoping the thinset between first and second layes will eliminate the movement issue which could crack the tile.

This is an open porch, therefore exposed to weather, so I want to make sure what I do will keep the tile secured and weather tight. If the only option is to tear off the Durock and start over, I will...I am just hoping I do not have too...
 
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#4 ·
ScubaGeekNC said:
Hello. Last weekend I started my tile project, of prepping my front porch for tile. (I framed porch with 2x10" joists, 16" OC with a run of 6'). I have 3/4" plywood ontop of that.

Ontop of the plywood I installed 1/2" Durock, and here is the mistake I made...I liquid nailed it down instead of using thinset and screwed the cement board 8" OC with 1 5/8" square heads. I thought it would be OK to use liquid nails instead of thinset, until I started reading the forums...which I should have done prior to starting this.

I really do not want to tear off the Durock, as I doubt it will be reusable. I was thinking since I will have to buy more Durock either way, can I just apply thinset ontop of the Durock I laid incorrectly, and add second layer of 1/2" Durock ontop of the thinset (screwing this second layer as well)? Will that eliminate any moving that may occur because of the gapping caused by the liquid nails?

I realize 1" of Durock doesn't add anything structurally, but I am hoping the thinset between first and second layes will eliminate the movement issue which could crack the tile.

This is an open porch, therefore exposed to weather, so I want to make sure what I do will keep the tile secured and weather tight. If the only option is to tear off the Durock and start over, I will...I am just hoping I do not have too...
It doesn't matter with any inches of cement board you use it does not prevent the tile from moving, it's your joists, footings and plywood, cement board is a filler to help bond the thinset to tile and thinset to plywood.

So why will we tell you to pull up the durock?.. Because now you will have movement from ply to durock which will lead in tile moving and popping, grout cracking.

What type of plywood did you use and how thick?

What type of tile are you putting down.
 
#6 ·
Also, I know adding a second layer of Durock wont add anything structurally.

I was just wondering if I treat that first layer as the subfloor, and use the thinset and add another layer ontop, if the Thinset and second layer of Durock would fix any movement that may occur because I place the first layer incorrectly.

I know I cannot go forward as it is, I am just trying to see if there is a way to correct without having to tear everything off.
 
#8 ·
ScubaGeekNC said:
Also, I know adding a second layer of Durock wont add anything structurally.

I was just wondering if I treat that first layer as the subfloor, and use the thinset and add another layer ontop, if the Thinset and second layer of Durock would fix any movement that may occur because I place the first layer incorrectly.

I know I cannot go forward as it is, I am just trying to see if there is a way to correct without having to tear everything off.
Well joe is correct about the osb that's just as bad as not putting the durock on correctly.

Are you shore you have the correct outside porcelain tile? I've seen many porcelain tile jobs done were they have used indoor tile so when it's wet and you have shoes on you slip and fall.

Well in my eyes I don't see anything that you can do to remedy this other then take it all up osb too or just Finnish it and hope that luck is on your side.
 
#9 ·
I'm going to ask a few questions and the return when you answer them.

Is the porch framing green treated wood or is it regular floor joists?

Is the porch subject to rain?

Does it get cold enough to freeze in your part of the world?

Are you hoping that this porch deck will shed water and be freeze proof?
 
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#10 ·
The entire porch framing is pressure treated.

The porch is covered, however when rains hard, the surface will get wet on the sides...the middle of the porch (it is 6' by 22') stays pretty dry all the time

I live in NC so it rarely gets below freezing, maybe a few times a year.

The porch floor is sloped, so there will not be standing water...it will run off.
 
#11 ·
I know that you want to get the job done as soon as possible---But that green treated wood needs to dry out before you can tile---

The shrinkage with that wet wood is remarkable---and the tile needs to be on a stable surface--

Osb swells up when in a wet or humid environment---so that will be trouble down the road--

I suggest that you use 3/4" BC exposure one (exterior glue) --then add a second layer of 1/2" BC on top--( the 3/4" meets the TCNA guideline but you are outside)

Then use Ditra by Schluter--or one of the other waterproof tile membranes---

If your porch butts against the house--also consider removing a row of siding and use a waterproof flashing.bonded to the Ditra,

Edge flashing will help keep the water from reaching the plywood decking--


I know---geez that's a lot of extra work---but might be the difference between a two year job and a 20 year job--
 
#12 ·
Thanks! After reading everything that I did not know anout how to do this job correctly, I think there is a lot I can do wrong with some pretty nasty consequences down the road. I rebuilt the entire proch ground up because of old rot, and I do not want to do that again.

I am thinking the best thing to do is tear everything off down to the joists and put down composite deckdeck boards instead. There seems to be less risk of my messing things up and I still get the appeal of low up-keep I was thinking the tiles would be.
 
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