Backerboard installation

CD08 · 10-23-2007, 01:12 AM

Hello,

I am installing a tile surround for my fireplace. I have a concrete subfloor and needed to raise the tile off of the subfloor because I will be also installing pergo floors. I need the tile raised so it will be level to or just a little bit higher than the floor. In order to do this, I attached 1/4 inch backerboard to the concrete subfloor. I used thinset and layed the backerboard down. I left for a few hours and noticed it was starting to come up around some of the edges.

I have since set packs of tiles over the raised areas to hopefully keep them down but I doubt it will hold. How can I fix this problem? Can I screw it to the concrete somehow? Thanks in advance for the help!

JazMan · 10-23-2007, 09:20 AM

I wouldn't normally recommend installing any CBU on concrete, but this should work fine for a small area if you do it right. You now know that you have to completely weigh it down however. Once the mortar skinned-over it'll have no bonding power. You need to rip it up and start over.

I'm not sure you needed to do that in the first place though. You know you need to install a wood molding where the laminate and tile meet, don't you? The laminate should be installed short of the tile to allow expansion, and the proper molding will cover the gap.

Jaz

CD08 · 10-23-2007, 01:18 PM

Well, I took the wieght off of the corner this morning and it seems to be holding well. I know about the moulding but when I looked at the height of the tile versus the height of the wood floor, the wood floor was higher than the tile. I thought it would look weird with the floor being higher than the tile so I decided to raise it a little so the floor would transition slightly up to the tile. I've never tiled or installed laminate before so I'm kinda learning as I go. Thanks for the reply!