Expansion joint on underlayment
#1
07-10-03, 12:50 PM
Expansion joint on underlayment
After spending all the time of screwing down the underlayment and at the same time taking care of leaving 1/8 in of gap between the boards, now is the time to install the tiles. Can anybody tell me that when I put the thinset mortar on the underlayment, should I take care of NOT filling up the gap with the thinset?
#2
07-10-03, 03:41 PM
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#3
07-10-03, 04:41 PM
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Just to clarify, Daniel meant that the techniques are similar to drywall. But the materials are certainly not.
Tape it with cementboard mesh tape, not drywall mesh tape.
Fill it with thinset mortar, not drywall mud.
And you don't need three coats like drywall. One coat will do fine.
Tape it with cementboard mesh tape, not drywall mesh tape.
Fill it with thinset mortar, not drywall mud.
And you don't need three coats like drywall. One coat will do fine.
#5
07-11-03, 06:33 AM
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Not sure about every manufacturer, but Wonderboard, DUROCK, and Hardibacker all want the joint filled and taped.
#6
07-11-03, 07:11 AM
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The gap between panels is not for expansion. You certainly don't want ANY movement!
It is there, so when you fill the gap with mortar, it is way more solid of a joint, then butting the panels together. Then the mesh tape is used to ensure the gaps don't move and telegraph a crack to the tile, just like a crack in a concrete slab will do.
It is there, so when you fill the gap with mortar, it is way more solid of a joint, then butting the panels together. Then the mesh tape is used to ensure the gaps don't move and telegraph a crack to the tile, just like a crack in a concrete slab will do.
#7
07-11-03, 07:52 AM
Thank you guys, especially Carpet-Done-Wright for the explanation. I am using cement boards, just forgot about the manufacturer. Now I know why it has to be done this way. Most of the time the manufacturer usually just ask you to do this and do that without explainning why. This is great.
