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-   -   Basement Slab Mess (https://www.johnbridge.com/vbulletin/showthread.php?t=127697)

RuINorOUT 06-27-2019 08:40 AM

Basement Slab Mess
1 Attachment(s)
Hopefully this attaches the photo.

cx 06-27-2019 09:25 AM

Welcome, Alma. :)

I've removed the useful parts of the thread you've been trying to delete and started you a new thread here.

Perhaps you could give us some more information on your intent. You plan to put ceramic tile on this floor?

Bottom line: No, you cannot effectively apply a crack isolation product such as NobleSeal CIS over that waterproofing membrane. I'm not familiar with that particular Grace product, but I've used their similar products regularly.

What is under the black membrane you depict?

My opinion; worth price charged.

speed51133 06-27-2019 09:59 AM

I had a VERY similar situation in my basement.


Read that thread. The flooring is holding up fine years later. I do have hydronic heat and keep the slab 60 in summer and 73 in winter. Humidity is also controlled with a humidifier and a dehumidifier. I also have 8 mil poly sheeting and 2in of foam under the slab. Under the sheeting there is literally about 6 feet of crushed stone and I am on a hill. I was originally concerned with the piece of pressure treated wood moving with humidity and temp changes, but it has not been an issue I can notice so far. The sliding door does get cold though. We hit like 40 below last winter.

RuINorOUT 06-27-2019 10:14 AM

original message
I deleted the thread because my husband said they were planning to put a threshold to cover that grace vycor plus flashing area. We just had a detailed discussion about it and decided that we could probably put 1/4" durarock over it to level that area out. However, he seems to be of the impression that we can just use thinset to level the areas that aren't perfectly flat. I have tried to show him the evidence against that - especially for a 24" tile. We are cleaning out the entire room now to throw a level on that floor because what I "thought" was level - he is saying is out 1/4" in 4 ft. So we are going to go put a real number on it. I'm telling him that if it's out that much then we do need to put a self leveling underlayment across the whole floor.

Original post that I attempted to delete:

Hi all! We came across this forum as we are searching for information on how to tile our basement appropriately. We are in the final stages of our home build. The basement floor was intended to be stained concrete. However, our incompetent GC (who we parted ways with last year) placed support piers at the wrong height, among other things, that caused the slab to be unsuitable as a finished floor. We wanted to place a concrete topping over the top of the slab; however, we have ultimately decided that tiling seems like it would be a cheaper and easier finishing method at this point. There is an expansion joint in one of the rooms to be tiled, and so we plan to place Nobleseal CIS over that joint (possibly the entire floor) before tiling. We are using 7x24 wood look tiles.

The question we have is about leveling the floor at the sliding door threshold. The basement is composed of ICF, and the slab did not extend over the ICF at the threshold, so there is an area of exposed styrofoam and Grace Vycor Plus flashing, that is 1/4-1/2" lower than the concrete slab. We have been unable to find any information about placing self leveling concrete underlayment with polyethylene flashing as a substrate. We know that it depends on which brand of underlayment we use, but what kind of primer should we put on this area before pouring the self leveler, if any? And can we just pour the self leveler in this small threshold area or would we have to pour it over the entire floor, even though the rest of the floor is relatively level? Or is there something else we should use to level this area prior to tiling? We found this Latapoxy Waterproof Flashing Mortar that adheres to flashing. Is that something we should consider using?

Thanks so much for your expert advice!! Our GC basically took us for all we had, so we are finishing all on our own now, and, after 2 years, the bank has decided they've had enough and have given us a deadline to finish - July 15.

RuINorOUT 06-27-2019 11:42 AM

under the vycor plus
Underneath the vycor plus is something like a 2x8 with concrete ICF underneath that.

RuINorOUT 06-27-2019 12:04 PM

1 Attachment(s)
So if we put durarock to cover that flashing, do we scribe it to fit as tightly as possible against the concrete and then put Nobleseal CIS to cover the remaining crack between the durarock and the concrete? Here's a little sample piece (not scribed) we stuck in there just to see how it might fit to fill the gap height wise.

Fast eddie part deux 06-27-2019 03:13 PM

Looking at thd first picture, with the doggie floor mat, looks like the edge of the concrete is inside thd thickness of the wall. What about an oak threshood as wide as the wall to bridge the slab edge. So like maybe an 8"×30" board. Then you could lay tile on the slab without worrying about the transition, and have something to pour thd levelling compound up to.

RuINorOUT 06-27-2019 03:54 PM

I tried to delete the thread because (after I posted) that's what hubby said they were planning to do - like a 9" wood threshold. I'm just not sure how an actual wood threshold would look meeting wood-look tile. :confused: His bother has been a contractor for 30 years so he asked him today what he should do with it. He told him to level it with thin set or mortar before laying the tile. My understanding is to NEVER do that - especially 1/2" thick.

RuINorOUT 06-27-2019 05:00 PM

1 Attachment(s)
So far we have cut a straight line in the concrete so that we can lay a piece of durock in there using thinset to level it with the concrete. We plan to cover that whole transition using a piece of nobleseal CIS (with noblebond) 24" x 71". Then use nobleseal CIS to cover the expansion joint in that room also. Since those joints run perpendicular to each other, we decided to run the tile in a direction to maintain the expansion joint and take our chances with the joint at the threshold. Any input is greatly appreciated.

Fast eddie part deux 06-28-2019 09:04 AM

Good point about wood grain clash. So maybe use a piece of azek.

Elkski 06-28-2019 09:44 AM

So you plan to use expansion joints? Possibly like the Schluter one with PVC flexible joint? Perhaps that would be good to isolate that strip of entry tile that you plan to put on that door ledge.

RuINorOUT 06-30-2019 09:15 AM

I was referring to the expansion joints that are already cut into the slab. I suppose we could consider placing one at the edge of the slab where it meets that threshold.

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