Hi All! I've got this section of tile that I installed last Nov. where I've just noticed several hairline cracks have appeared. I've knocked on all the tiles and they all seem to be well bonded. I'm wondering what I've done wrong The installation was done w/ Ditra following their installation guidelines to a "T" and the floor meets the requirements for porcelain tile. I also used TEC grout. As a side note, the cracks appeared just recently after our crawlspace flooded while we were out of town for an extended time (busted irrigation hose right outside the house). The side of the house where the cracks are located is where the majority of the water was pooling. I'm not sure if that has anything to do with it or if it's something else.... TIA!
Suzi

 

So, you're good for six months, then the crawl space floods and now you have cracks?

Might be conicidence but you could have had movement in the floor caused by the water.

 

If I didn't mix the grout properly, would the cracks have shown up sooner or is this about the right time frame? I thought I read that if it was a bad grout consistency they'd show up within a month or two.... I have not idea if it's related to the crawlspace flooding or not... That's why I'm asking.
I have more tiling to do in this house, so if it's a mistake that I've made I want to make sure I don't repeat it.

 

After checking out all the tiles that are on the main floor, it looks like the grout is cracking in every room. Some of these I laid and grouted 1 yr ago, some 6-9 months ago, and most recent was 3 months ago. I know they were ok as of a couple months ago. Since it was my first big tiling project (even though I just did one room at a time), I would keep checking to see if there were any issues/lessons to be learned.
So, the question remains. Did I mix the grout wrong or could this be from the house flexing d/t the excessive water in the crawlspace?

 

No Tile expert...but it would stand to reason that since the moisture level in the crawl probably went through the roof (as in high numbers...not your actual roof)....the lower areas of wood (joists, plywood, whatever is exposed) would absorb that and expand...probably bowing the upper layer.

 

Ok, so then *if* the moisture in the crawl is what has caused this, and it happened at the beginning of July (~2-7 July), and it was pumped out then, then how long should I wait for the house to dry out so I can finish tiling the downstairs? I just laid some ditra down to tile this little hall and laundry closet (~45 sq ft total) which would complete the entire tile work downstairs. I'd love to be able to finish the install but I can lay down some ply over it if I need to wait. It's been in the mid-upper 90's here for the entire time.

 

There's no way for us to tell you how long before your crawl space dries out. Get a couple of those remote temp/humidity gadgets and monitor. Hopefully the landscape is slopped the right way and the space is vented per local standards.

Could be any one of those. If you'll give us the specs of how your framing is built and what you've got for a subfloor, we may be able to help.

Jaz

 

The house was build in 96' and has 16" OC joists that are 2x10 I think... I have preggy brain right now and can't remember off the top of my head. Then there's 3/4" TNG OSB with either a 5/8" or 3/4" layer of ply on top of that.
The flooding wasn't just a one day event We are guessing that it was flooded for ~1 week before a friend called and told us what was going on, shut off the water and pumped out the crawl for us since we weren't coming home for another week at that point. So, there was lots of water being drawn up into the house Ahh, the joys of going on holiday for a long time....
I just find it a bit odd that everything was ok before we left, and the upstairs BR I tiled 18 months ago is fine, and the main floor is now cracking....

 

Suzi

You don't say what size grout joints you have, or if you used sanded or non-sanded grout.

It would be my best guess that the flooding is the culprit hear. OSB and plywood subjected to that amount of moisture/water will most definitely swell and warp. Even after it dries out, there could be issues. Ditra will help with any horizontal movement of the floor, but it will not help much (if at all) the vertical movement from the subfloor/underlayment swelling and warping. You need to wait and monitor the humidity conditions (as Jaz said) before going any further. Be patient and make sure that its done all the drying out that its gonna do. Once you are comfortable that conditions are normal, you need to evaluate what you are left with. Check the tile to see if they are solidly bonded, check the floor to see if it is still flat, etc.

Its possible that the tile are still bonded well to the ditra and the ditra fabric is still bonded well to the plywood, but the fabric could separate from the ditra if the subfloor is buckling. I saw this happen once with a job I did, where there was excessive flooding on the floor from a plumbing leak and water was present for about a 2 week period totally soaking 2 layers of plywood. When we demo'd the tile, it appeared that the fabric took the contour of the warped plywood floor while the waffle part stayed flat and bonded to the tile in a few areas of the floor. Had cement board been used instead, it's likely that the tile would have cracked in the warped areas. It sounds like your situation isn't as bad as this, as you had moisture underneath but not standing water on the floor.

If it turns out that all is ok, you can then give removing the grout and regrouting a shot. You need to remove enough of the grout to give the new grout something to bite onto. Remove at least 1/2" the depth of the grout (a little deaper is better). If you leave some of the old grout, don't expect a perfect color match. Make sure you use the right grout (sanded or non sanded) depending on grout joint size. Make sure you use new grout that is not out of date. Don't use old grout that has been sitting around in an opened bag. Pay careful attention to mix the grout according to the TEC's instructions.

 

Johnny,
The grout joints are 1/4" and I used TEC sanded grout. There are field expansion joints every 8-14' depending on the room location and that was done with TEC sanded caulk. No grout between the tiles and the drywall or baseboards. So far, just knocking on the tiles they all still sound like they're still firmly embedded..... Hopefully that won't change and hopefully the fleece is staying put.... I know there will be some color match issues with the grout, but it is what it is.

So, I should wait until I'm confident the crawlspace is as dry as its going to get to regrout. That's not a problem. But, should I also wait on the last 45 sqft of tile I was hoping to finish this week? The ditra is already down and I would love to be able to move the w/d back in its place to do laundry this weekend.... And then I was going to finish out the living room on this floor w/ a wood laminate in two weeks, should I also put that on hold until the house finishes drying out? I'm due w/ our 2nd baby in Nov. and I'm just trying to wrap up these last couple flooring projects before she gets here
Thanks so much for all the feedback and help guys! I can't tell you how much I really appreciate it!
Suzi

 

So what's the temp and relative humidity down there? Record both several times a day and compare to outdoor numbers.

Jaz

 

Ok, but question.. Isn't a crawlspace normally a little bit more humid that the outside, at least in the Deep South where we're so stinking hot and humid all the time?

 

Without monitoriing the humidity changes, its hard to say if its ok or not to go ahead.

In the mean time, you have a lot of grout removal to do before you can regrout and thats gonna take you some time. Why not go ahead and remove all the cracked grout. That'll give some extra time for the crawl space to dry out and you'll still be getting some work done.