Hairline cracks in Self Levelling Underlay

Discussion in 'Floor Preparation' started by RyanD, Sep 9, 2009.

  1. RyanD

    RyanD New Member

    I recently filled a small low spot in my condo floor (concrete), max depth about 3/16", with a Mape self levelling material. The floor was clean, primed with a Mape primer etc and has no cracks. It was a somewhat warm day with low humidity. There were no fans running. About three days later, very small hairline cracks are visible. We did not walk on the patch for twenty four hours as recommended.

    My question: Is it safe to glue down engineered wood on this patch? I'm worried the cracking will continue and eventually separate from the floor.

    I emailed Mape but thought someone here might have more experience with these levelling underlay products and whether hairline cracks are a concern.
     
  2. Tandy Reeves

    Tandy Reeves Resting In Peace Charter Member I Support TFP Senior Member

    In all likely hood the batch was not mixed as stipulated by the instructions. On this product the instructions must be followed to the letter. If it says mix at 1200 rpm for 3 minutes, you cannot mix longer or shorter at higher rpm and succeed.

    In my opinion, the cracking is through unless there is floor movement and not deteriorate. This is a great product with a high psi.
     
  3. Peter Kodner

    Peter Kodner Inspector Floors Charter Member Senior Member

    I have seen this in SLCs when the water ration was incorrect. As Tandy said, you have to follow the directions on these to the letter! One of the reasons most at TFP recommend these products for pros.

    Tap it gently with a solid object and listen for any hollow sounds. If you hear them, it is not bonded correctly to your substrate.
     
  4. RyanD

    RyanD New Member

    Thanks for the replies. We followed the instructions closely. It was a very dry day when we poured. The cracks are micro... 1/4 mm in width. You need to really look, with a flashlight etc, but they are there. There is no hollow sound when tapping but i'll try again and listen carefully.

    My major concern is this all cracks up after we glue the floor down.
     
  5. Steve Forbo

    Steve Forbo Pro Member

    I have seen this with both Mapei and DryTech. Unless there is a bonding issue and or hollow spots, just feather finish it and you will be good.
    Mapei has a tendency to shrink and create these spider cracks as do other polymer based products.
    I have seen it hundreds of times and it has never been a problem in the ling run.
    As long as the product is mixed right and prepped right, you should be good with a little touch up.
    Another reason I hate everything Mapei makes....LOL
    I know it's cheap, but you get what you pay for in the long run.
    Steve
     
    Last edited: Sep 9, 2009
  6. Tandy Reeves

    Tandy Reeves Resting In Peace Charter Member I Support TFP Senior Member

    Wow Steve, I think you should put in front of that statement about Mapei "in my opinion". I disagree with that statement 100% and I think others will also. I too have seen many floors patched (maybe not 100s), and I have yet to see one fail. In fact if I can find them I will post pictures of a floor that was so badly prepared that I told them if they put Plenti Patch over it I would walk away and not continue to consult with them.

    Well they put down the patch and it looked absolutely horrible. They polished it as best as they could. Still looked horrible and owner said he was not going to pay for a floor that looked like that. Flooring contractor sued and lost. You know that ugly monster is still performing very satisfactory.

    Also why would it be necessary to feather patch spider crack when the adhesive being spread would do the same thing.
     
  7. cproader

    cproader All over T's last nerve Senior Member

    :eek:...........Ryan, did ya let the primer dry good before ya poured it. Ya did prime it didn't ya............:hmmm:............:welcome:
     
  8. Barry Carlton

    Barry Carlton I Support TFP Senior Member Published


    Didja read his post?

    b
     
  9. cproader

    cproader All over T's last nerve Senior Member

    :eek:...............:brick:
     
  10. Barry Carlton

    Barry Carlton I Support TFP Senior Member Published

    Can't help but notice how often you use [ :brick: ] ...you sure must have a dooosey of a head ache

    b
     
  11. Steve Forbo

    Steve Forbo Pro Member

    I am speaking from pure experience. Neither of us were there and have no clue what caused it. But I can guarantee it is from either poor prep or poor mixing.
    One of the biggest problems I see in this industry is the FACT that 90 out of 100 so called good installers can't patch to save their lives. And it is especially directed towards soft goods installers.
    I have yet to see a job that needs more than 2 to a max of 3 coats of patch in my life. Yet I have seen people/companies put down skids of patch and still get horrid results.
    But what scares me most, is the fact that you are a certified inspector and make a statement like,
    "Also why would it be necessary to feather patch spider crack when the adhesive being spread would do the same thing."
    You couldn't be more wrong any way you slice it.....
    For an experienced installer that takes great pride in what he does, I would be ashamed at making a statement like this. The fact of the matter is that many of the materials I work with will telegraph even spider cracks due to the static pressure and tinsel strength of the adhesive, and the material will look like crap in a short amount of time.
    This is the exact reason why I posted in another thread about "so called" inspectors...... The problem is when it comes to a real problem in court, the word of a person who knows nothing about the reality of the installation will help someone win, even when they are 100% wrong. Simply because they have some BS certification in inspections.
    It's the same reason why bridges fall down a week after they were inspected by a so called professional.....

    So, in short, it is NOT MY OPINION, but it is indeed facts of what I have seen. Just because someone never wrote it in a book or spoke about Mapei in a seminar means diddly squat to me....
    I go by what I see in reality after working with said materials... The End.
     
  12. Barry Carlton

    Barry Carlton I Support TFP Senior Member Published

    Steve, re read what the product is that is going over the patch. Spider cracks will not telegraph though wood.

    b
     
  13. mcurrin

    mcurrin Charter Member Published

    The thread is about concerns of spider cracks affecting the installation of glue down engineered wood. I'm just a so called "inspector", and not a wood inspector, but I fail to see how the cracks would telegraph through to the surface of wood. I would agree with you if it were a vinyl floor, but since it is wood I think I will agree withe everyone else.

    Mike
     
  14. Tandy Reeves

    Tandy Reeves Resting In Peace Charter Member I Support TFP Senior Member

    In all your vast experience how many time have you seen spider cracks telegraph through engineered wood? In all of your vast experience surely you have photographs of this as well as other floor coverings showing this problem.

    Why not share them with us. I am according to your writing a dumb inspector and sure could be educated by someone of your high stature Your Highness we stand in awe of you. :mad::mad::mad:
     
  15. Peter Kodner

    Peter Kodner Inspector Floors Charter Member Senior Member

    King, at the risk of offending you, tinsel is hung on Christmas Trees. Tensile strength is the ability of a material to resist deformation, normally stretching, under stress.
     
    Last edited: Sep 9, 2009
  16. Barry Carlton

    Barry Carlton I Support TFP Senior Member Published


    Ummmm, Do you mean Steve?

    b
     
  17. Kman

    Kman Tile Expert I Support TFP Senior Member Published

    I've been using Mapei's products (mainly thinset, grout, SLC) and have never had an issue with any of them. :yesss:
     
  18. Lo Down

    Lo Down Old as dirt member Charter Member Senior Member

    First thing I see is what Tandy saw. The product was engineered wood, not thin shiny vinyl. Looks to me like that was the only issue he was responding to.
    Second thing was the:
    Those of which you speak of don't bother to do prep in the first place. :D
    That said, I think the numbers of successful installations of floor patch are considerably higher....................... tho you are correct that the # of sloppy installers these days can can be overwhelming.

    Spider cracks in themselves do not mean the underlayment is going to fall off the floor................. It's adhered well, just slightly out of tolerance. I bet if the installer called Mapei, they would have confirmed that all was fine.
    If the installation of self levelers were totally "rocket science", the product could not be installed without a barometer, thermometer, a digitally speed controlled mixing drill and proper mixing paddle, and a container that had altitude adjustments to accurately weigh the non chlorinated water prior to pouring the leveling compound into a climate controlled room inspected and approved by Mapei.

    I have only installed a small amount of these self levelers, and after my first "so so" pour, I realized they needed to be mixed as close as possible to what they say. Live and learn.:yesss: I let it dry for a week just to be sure. Turned out fine and that was 15 years ago.

    Your comment was dead on Tandy, so don't sweat it. I think Forbo was including sheet goods in his comment.
    We all know that manufacturers understand that human error needs to be compensated or factored in to the installation of these products. + or - a 1/2 cup of water in two bags isn't going to mean a failure any more than an extra 168RPMs of drill speed.
    .......... just keep as close as you possibly can to the specs................ especially so with self levelers because they certainly ain't your average floor patch.
     
    Last edited: Sep 9, 2009
  19. Kman

    Kman Tile Expert I Support TFP Senior Member Published


    Don't forget a stopwatch.
     
  20. Lo Down

    Lo Down Old as dirt member Charter Member Senior Member

    ....and the factory required on site observer with camera in hand and weather station set to record the events prior to, during and for 72 hours after the pour. :D
     
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