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jsclimbs

Underlayment question for engineered wood on concrete slab

jsclimbs
14 years ago

We have a slab that is moist because we live at the bottom of a hill. For example if something sits on the slab for 15-30 minuted and then removed, you can see the moisture. We are thinking of using the Floor Muffler underlayment under a BR111 Triangulo Amendoim engineered floor. Is that enough or should we lay a plastic vapor barrier too? OR should we also seal the concrete slab first, then plastic, then the Floor Muffler? We are doing this ourselves. 2nd question, when floating the floor and gluing the tongue and groove, do we tape the boards together or strap them together and then let them sit until the glue dries? Thank you for your advice in advance.

Comments (10)

  • woodfloorpro
    14 years ago

    If you are going to float the floor you need the plastic, 6mil. overlapped 6" + go up the wall a bit. If glued the slab needs to be sealed well first.

  • jerry_t
    14 years ago

    Imo, you need a good sealer regardless, that is just unacceptable. The manufacturers instruct customers not to proceed if a mat test shows moisture. I would contact the flooring manufacturer and get their guidance.

  • jsclimbs
    Original Author
    14 years ago

    What kind of sealer would you use, for floating application.
    The Bostik MVP seems expensive if I'm not going to glue the floor. Is there a cheaper roll on kind of sealer that would work?
    Thanks.

  • phila_2009
    14 years ago

    It is expensive for a reason.

  • uniquewoodfloors
    14 years ago

    If your slab as wet as your described, I would certainly recommend to use MVP or something similar to seal it first, then Floor Muffler, then float your engineered T&G floor on top.
    I want to talk a more about your floating T&G engineered flooring. These types of multiply engineered wood floorings are usually designed for glueing down application when solid hardwood flooring are not suitable to use, such as in a condo project,basement or main floor slab subfloor. So the tongue and groove are usually not milled tight enough to hold the T&G in place after the edge gluing. So the boards will tend to separate before the glue dries. If it is random length products, installation will be even harder with some boards are shorter. However most of the engineered flooring brands allow to float their flooring to cover more market or applications. To me it may not be a good choice for DIY home owners simply because they are not as easy as the traditional European style longstrip 3 ply floating wood floors to install. Even without Click Lock system, a T&G 3 ply engineered wood floors are very tight to tap the tougue into the groove. So when glue applied in the upper part of the groove, the tongue will stay tight once tapped into the groove. I guess this is the difference between an engineered wood floor and an engineered floating wood floor, which we are asked all the time by confused consumers.
    So the answer to your quesiton is: If the tongue and groove is tight, you can edge glue without using the strap. If not, you'd better strap them.I hope my 2 cents will help.

  • jsclimbs
    Original Author
    14 years ago

    Thanks for the 2 cents.
    I just finished grinding down some high areas in the floor.
    What a messy job.

    We are thinking of putting down 30lbs construction paper, then 6 mil plastic , floor muffler, then float the floor.
    Would this be OK?

    If I must use Bostik MVP ,I would rather glue down the floor for a more solid feel. We were reading that Bostik will give out fumes that may be harmful. We have a 4 year old in the house during all this.

    If I was to strap down the boards, one must stop every 6ft then strap them and let the glue dry before proceeding?
    This will take a long time. Tape will not do in this case?
    We have not seen the wood yet, it's being delivered on Monday.
    Also the BR111 Triangulo is discontinued, according to .truehardwoods.com . We ended up with Triangulo, a company that made the floor for BR11 then branched off on their own.
    Thank for your help.

  • jerry_t
    14 years ago

    Your slab has a known moisture problem. You need to address that issue first. The mat test you performed is considered an indicator test. When that test shows moisture someone should be doing further testing such as a calcium chloride test. It will show how many lbs. of moisture per 1000sf in a 24 hr. period. When you know that fact, then you can determine if Bostik, Mapei or another sealer will work the best, considering the results the CC test confirms.

    If you proceed without sealing the slab you'll end up with alot of moisture building up underneath the poly, and that is neither good nor healthy because it will eventually find it's way up.

  • jsclimbs
    Original Author
    14 years ago

    The moisture problem is mostly due to a flood we had a month ago. Water got in to the house from our neighbor's yard. They had some landscaping done and it caused the flood.
    That is being fixed. We had Pergo on for the last 8 years, with no problem, until the water got on top of it.
    When I removed the Pergo ,I found no mold under the vapor barrier. Most of the water was on top of it.
    We just noticed the moisture under things that we move around, on the slab, as I replaced the lower drywall.
    This may have been there all along, or is moisture from the flood.

  • uniquewoodfloors
    14 years ago

    jsclimbs
    Keep us posted on the your fooring project.

  • jsclimbs
    Original Author
    14 years ago

    The flooring we ordered from truehardwoods.com. arrived and left as soon as my wife opened a box and noticed it was not the wood floor we wanted.
    We ordered BR111 Triangulo Amendoim, in 3/8 thick, 3 1/4 wide planks. After 2 weeks they called and informed us that was on back order, and not available until April.
    The company that made that flooring for BR111 was going on their own, and it will be a while.
    But they had something that looked the same, made by the same company.
    Well it wasn't.
    So we are back to picking a floor.
    This weekend we're going to a few local warehouses in Los Angeles, maybe we'll find something in stock, that we like.
    Any input on what brand to go with?

    At this point I am open to float or glue installation.
    Bostik MVP and Bostik glue is expensive, but it seems the way to go is moisture is present.
    I found the Bostik Best glue for 100$ a 5 Gal bucket on Craig's list.
    The only concern would be the toxic fumes that would be released for years after the application.
    If I decide to float, I was thinking of a product I saw at Home Depot. Red Gard that I could roll on ,then install a 6mil vapor barier, and padding.
    I did not like the floating Pergo we had before the flood.
    The usual reasons, hallow sound, flexing in some places.
    For now we are enjoying our bare concrete floor,that seems to be getting dryer. Just don't set anything on top.