how much flex should a slate floor have?
Dear all, I’ve got a situation here. I’m trying to finish my bathroom I recently put down my wonderboard and put some slate down with what my HD said was the best thinset.It was a two part mapei product I put all the tiles in I let it set for three days just to be sure. I was cleaning out the thinset form my future groutlines and discovered this thinset is a little bit rubbery. Not only that but when I’m stepping between two tiles they actually have a little flex. Is this acceptable or normal? or do I have to pull all this stuff up. Or does the mortar work as some sort of a stiffening agent. It doesn’t flex so much that you’d ever notice walking on it, more so if one was to stand and shift weight around over a few. Any suggestions
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a 2 part Mapei product? Most thinset is sold in a bag and will need water and perhaps a latex additive to make it useable. You sure this wasn't mastic? Not to take a potshot at HD employees (I'm being nice dadgummit), but most of them don't know mastic from their butts...
If it was mastic, then a lot of times it takes a LONG time for that stuff to harden and some never really does get hard. Mastic is not really for a wet location, but it has been used - if you're lucky it will hold up for a long time.
If it was real thinset mortar, then it should be about as hard as my wife says my head is after 3 days...
Edited 11/15/2005 1:49 pm by Greg
You can check out http://www.johnbridge.com/vbulletin/deflecto.pl to see if your floor structure will even allow for the slate.
I recently put down slate and used TEC brand FullFlex thinset (1 part). No discernible flex whatsoever. The generally accepted industry standard maximum deflection for natural stone is L/720 as compared with L/360 for ceramic tile. Are you sure your subfloor isn't flexing?
I'm reasonably sure that my subfloor is solid, I've got doubled up joists, (old and newones sistered) and glued and screwed with 3/4 ply, the span is only about 8 feet total. The cement board is over screwed if anything. I'm wondering if the flex is actually there or not. Maybee just the skin of me feets pushing between the tiles giving the sensation of the tiles pulling together when infact its my skin jamming inbetween two tiles. I went a head and grouted it, that seemed to go o.k. if I'm pulling it up in a few weeks I'm going to be back asking for step by step instructions from materials to technique to timing. Until then thanks for responding to my post.
I presume HD meant Home Depot, I wouldn't trust their advise especially on something as unforgiving as laying tile.
Your subfloor and span does indeed sound fairly stout, hopefully it is your imagination.
now that you have grouted your floor you can look for tell tale signs like cracks in the grout or cracks between slate and grout rather than that "feeling" you get when barefoot
Have you ever heard of someone using a cauking on top of their grout. My friend was saying he did this, I can't see how it would work or even look nice.
You've been hanging around with the wrong crowd.<g>
My friend also told me to us a mastic called omni grip. I decided against it after reading some things about tiling in general. What do you use to get grout out of the different textures of slate. It would be easy with ceramic but this slate seems to have hundereds of hiding places for grout to hide.
Well, you try to clean up the grout before it sets up. Just keep wiping it down with clean water. A stiff nylon brush would help clean out the crevices. And seal it as soon as possible with a good quality sealer.
On another thread somebody suggested a light coat of sealer for rough stone before grouting. Have you ever try this? If so did you find easier cleaning up the grout?
I have presealed slate and limestone before. Primarily to prevent the grout pigments from discoloring the stone. I'm not a professional tilesetter, but I have done a fair amount.
The johnbridge.com website is a good place to get definitive answers.
Ever try doing white limestone 18x18. What a nightmare!! You better seal it first!!!!!!!! Should be a warning label on every piece.
Sealing any single colored porus natural stone first is always a good idea.....on white limestone its a must! I just keep the sealer away from the edges/sides as much as possible to allow the grout to grip better.
Be poultice
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