Efflorescent salts appear after porcelain tile installation

Discussion in 'Ceramic and Stone Q&A' started by GulfCoastHotSlab, Dec 7, 2017.

  1. GulfCoastHotSlab

    GulfCoastHotSlab New Member

    I have 20" porcelain tiles on hand-mixed thinset over cleaned bare slab (no barrier). Total job was just over 1100 ft2, so roughly 1/2 the downstairs area.
    Within weeks we see the white efflorescent salts. We knew this was possible as we had taken up a vinyl tile floor from the same area that had been installed over a thin set float over a TiteBond moisture barrier then latex glue about three years earlier in a partial downstairs 'update'. That floor lasted two years but was failing within one year. We had the porcelain tile installer jack hammer out the float (and thus the moisture barrier / residual glue) before letting him set the new tile directly on the slab.
    We have had two civil engineers (both PE's) to the house since to advise on the issue and investigate drainage (seems to be the natural starting point). Nada issues, though I have spent the last year reducing dirt levels around our slab and adding some additional drains. And I have had a plumbing inspection service both video our sewer / drain system and do a static pressure test. Again, no issues. All pressure potable piping is above ground in our area. No water lines under the slab. I have pressure checked on sprinkler system lines that are near the slab. Nada issues.
    We live on the upper Texas Gulf Coast on land developed 45 years ago from raw pasture land. Typical clay layers starting some 18" below grade. The house was built in a period (1978) when plastic sheeting was spread for a vapor barrier; its status today cannot be determined. House as no major slab movement but one partial crack across the back middle of the house. No observed water staining near that crack when the original carpet / pad were removed for the vinyl floor.
    The main salt shows are in the den (where the partial slab crack exists) and over into the breakfast room. No shows in kitchen or laundry area. And the slat shows we do have are always in the same place. We wipe them up every two weeks or so, and within a week there is enough to be noticeable. As a reference, when the water comes up to the grout top, it pools as clear water in a puddle ranging from barely visible to maybe an inch by three inches. When it dries you see the salt show.
    We went through 30+" of rain with Harvey, and there was at the time and has been since no difference in salt shows - volume, how quick they appear after cleaning, etc.
    Currently just living with the salt shows. No tile failures. Theoretically the installer offers a Lifetime Installation Warranty, so if a tile pops, then I can to them and seek some relief. Interested in the back-butter step mentioned in a post above. Certainly that was never discussed or done on this floor. Installation company is a large chain store, at least in our area.
    If anyone has further action steps or advice I am open to suggestions.
    Thanks for taking the time.
  2. Incognito

    Incognito No more Mr. Nice Guy! I Support TFP Senior Member

    it's not coming from back buttering or failure to do so

    probably the concrete/moisture issues

    possibly somthing in the thin set or grout------(highly unlikely)
  3. Elmer Fudd

    Elmer Fudd Administwative Asst. Charter Member I Support TFP Senior Member

    As far as a lifetime installation warranty I would kiss that goodby as the installer is NOT responsible for YOUR moisture issues.
  4. Mike Antonetti

    Mike Antonetti I Support TFP Senior Member

    Thin-Set and grout used was probably Portland based, notorious for efflorescence. First sentence you say “hand mixed” what does that mean? Did he make his own thinset?

    Anyway if problem was known beforehand then there are thinsets and grouts specifically made to not effloresce. Different type of cement. Usually knowledgeable tile setters will use them in exterior applications.
    • Like Like x 1
  5. epoxyman

    epoxyman Pro Member

    Back about 15 years ago I did a tile floor right at 2,700 sf at a eye doctors office
    After we grouted it about 2-3 weeks later the joints started to turn white haze so I got my Dal tile rep to come out and at that time customs building
    Products grout was having problems with there lipstick red grout doing this
    We talked with the GC and the doctor
    And let the floor set for over one month then we did two light cleanings with acid wash and all was good.

  6. GulfCoastHotSlab

    GulfCoastHotSlab New Member

    Forgot to add in my original post that several houses in our area of the neighborhood have varying levels of slab moisture problems. Some as simple as water collecting under a chair mat laid on carpet in the home office. Others with moisture high enough to rot the wood floor in a bathroom base cabinet.

    My regular moisture checks on the exposed slab in our bedroom, which is on the main floor next to the den with the tile, using the calcium chloride kits show around 9 (lbs/1000 ft2/24 hours) over the last year. When we first pulled up carpet in the den some four years ago to put down the vinyl tile, the reading in the den was 6.3.
  7. Incognito

    Incognito No more Mr. Nice Guy! I Support TFP Senior Member

    The calcium chloride tests are confirming that you'd need remediation. They will give very different results over time depending on the local weather, landscape and groundwater circumstances.

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.