# Attaching Backerboard to old Fireplace surround



## cody21 (Jun 14, 2009)

We will be putting new Tile over the old red brick surround of our Fireplace as part of retrofitting it with a Gas Insert. The Home Depot guys are all over the map in recommendations on how to do this. (duh)..

One guy suggested simply using quickset mortar to "build out" and level the grout joints & surface area, then use a regular thinset to attach the Tiles.

One guy suggested just screwing in a sheet of Backerboard directly over the existing bricks.

I like the idea of the 2nd opinion - seems less "messy" and a better way to get a level surface to tile onto. How would we attach this Backerboard to the brick surface? Drill and anchor bolts? Are there "nails" that can go directly into brick or the old mortar joints?

Do you agree with their assessment or is there a better way to do this?

Thanks so much in advance.


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## joecaption (Nov 30, 2011)

I've always use thinset to level it out, let it dry and check for high areas, Grind then down if there is any, and and used tap con flat head screws to attach it.


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## cody21 (Jun 14, 2009)

Thanks ! PS - what are "tap Con" screws ?? Do they screw directly into the thinset without drilling? (e.g., self-setting screws?)


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## joecaption (Nov 30, 2011)

Nope, going to have to use a hammer drill to predrill the holes.


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## cody21 (Jun 14, 2009)

Got it ... thanks


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## Tscarborough (Mar 31, 2006)

Mortar for scratchcoat, then attach with thinset.


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## cody21 (Jun 14, 2009)

Yea, I've read (ad nauseum mind you) 3 different approaches to this project. One, like you mentioned, is just to apply Mortar, then a Thin Set with adhesive added & the tiles. Another suggestion was to just use Thin Set, period - build it up over a couple of coats (over 2 or 3 days) and eventually just place the tiles. The other suggestion was to screw in some firring strips & attach backerboard, then thin set with adhesive & tile.

The main issue I have is that the existing bricks are not all flush -- there is a sort of mantle area that has 2 rows of bricks sticking out about 1/4 inch further then the other bricks. So we'd basically have to (1) build up the mortar (or thin set) to at least that 1/4" ... then another 1/8" or so beyond that to get a flush surface to mount tiles. Hence the approach of just shimming a piece of backerboard seemed like a good approach. 

Thanks for all the input guys ...


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## DannyT (Mar 23, 2011)

why build up the whole thing to meet 2 rows of brick when you can take a grinder or a hammer and chisel and just chip them off flush with the rest of the brick


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## cody21 (Jun 14, 2009)

Good point ... but not sure how easy that will be to do ... We'll try that first as you suggest.. thanks !


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## Tscarborough (Mar 31, 2006)

Thinset is not meant to be applied as a filler, hence the name THINset.


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## cody21 (Jun 14, 2009)

Yea, that was always what I thougt as well ... hence if we go the "fill it" route, we'll just use Mortar, then the thinset to apply the tiles. Otherwise we'll go the backwerboard route and use firring strips to level it out.

Thanks again for everyone helping me sort through this.


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