Subfloor

Discussion in 'Hardwood Floors' started by wcheaib, Apr 12, 2017.

  1. Apr 12, 2017 #1

    wcheaib

    wcheaib

    wcheaib

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    Hello All - I am in the midst of renovating my basement. I have decided to install finished on-site engineered hardwood. My contractor recommended that I install a subfloor (5/8th inches) above dimple board. I noticed that he is pre-drilling through the concrete every 16" and inserting a 3" tapscon screw. I am far from an expert in home renovations, let alone subfloor installs, but should he be drilling all the way through the concrete slab? I am concerned about a few things: (1) water penetration, (2) cracks in the slabs given the number of holes I have now, and (3) loose screws given there is nothing in front of the screw now. Should he not just drill a little more than the length of the screw, vacuum the excess powder and screw the tapscon in? Appreciate your thoughts on this.

    thanks
     
  2. Apr 12, 2017 #2

    Floorist

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    Any moisture barrier you had is now gone. He is doing it wrong.
     
  3. Apr 12, 2017 #3

    wcheaib

    wcheaib

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    Thanks. But it is a fixed system as opposed to a floating system so he does have to nail/screw through the concrete. Are you saying the fact that he went all the way though is wrong? Or screwing into concrete through the dimple board is wrong? thanks again
     
  4. Apr 12, 2017 #4

    Ernesto

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    Whats a dimple board? Most slabs are 4 inches out here in the southwest - land of concrete.
     
  5. Apr 12, 2017 #5

    Nick

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    there 4" here to E on the east coast.
     
  6. Apr 12, 2017 #6

    Floorist

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    4" here too and if he drilled all the way through, the vapor barrier is gone.


    QUOTE
    "but should he be drilling all the way through the concrete slab? "
     
  7. Apr 12, 2017 #7

    wcheaib

    wcheaib

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    We have 4" of concrete here in Toronto as well. The dimple board is called DMX 1-Step. And yes he pre-drilled all the way through the slab (basically hit the gravel). Sorry - what do you mean by "the vapor barrier is gone". Does that mean water can penetrate through the tapscon screws up into the hardwood? Thanks again
     
  8. Apr 12, 2017 #8

    Floorist

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    Yes it can. Plastic sheeting is installed before the slab is poured to keep out water vapor. He probably put holes in it.
     
  9. Apr 12, 2017 #9

    wcheaib

    wcheaib

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    I am certain I have no plastic sheet as we had to break the concrete to move a bathroom. What I do have is some gravel underneath the slab.
     
  10. Apr 13, 2017 #10

    Jon

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    I Googled this DMX 1-Step and I would wonder not knowing much?
    Seems strange to a lino layer
    What you timber guys reckon?

     
    Last edited by a moderator: Apr 4, 2018
  11. Apr 13, 2017 #11

    Nick

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    I wouldn't want to work with that crap. :sick:
     
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  12. Apr 13, 2017 #12

    wcheaib

    wcheaib

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    This is a cheaper version of the DriCore system (http://dricore.com/nw/index.php) whereby you screw down plywood above this dimple wrap. It effective creates a barrier between the cold concrete and the engineered hardwood. The issue I have is that when it was pre-drilled, they drilled right through my slab. So I have swiss cheese of a slab now every 16" square inches.

    The framers did it this morning and they tell me they do this all the time. Not sure if they are full of BS.
     
  13. Apr 13, 2017 #13

    Floorist

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    Here in the US, building codes require a plastic sheet to keep out moisture, otherwise you can get black mold growth on the concrete.
     
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  14. Apr 13, 2017 #14

    Nick

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    You can see it on the post from In.
     
  15. Apr 14, 2017 #15

    highup

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    You need to be telling this to the Dri-core people and see what they say.
    We're just guessing.
    Not knowing any better, I see zero reason to intentionally drill all the way through the concrete. Why not 2 or 2 1/2"? Drilling into the gravel below has no holding power, so the only reason to do that is they have no depth stop on their drill so they are just ensuring the hole is plenty deep. Hammer drills have adjustable depth stops so that you can drill accurate holes.
     
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  16. Apr 14, 2017 #16

    Nick

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    Even if they don't , What does it take to rap a piece of tape around the Bit .

    They just don't have any clue !!
     
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  17. Apr 14, 2017 #17

    Jon

    Jon

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    And when the flooring goes all wrong they will blame the layer
     
  18. Apr 15, 2017 #18

    Nick

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    Certainly Mo!
     
  19. Apr 15, 2017 #19

    wcheaib

    wcheaib

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    Where should I go from here - do you suggest I rip up the subfloor and plug the holes (there is about 2,000 of them)? The basement is meant to be the living area for my elderly parents so it's not a recreational space that will be used infrequently. They literally will be living down there. I need to protect against moisture, water, mold, etc. Just not sure how to fix this at this point.
     
  20. Apr 15, 2017 #20

    Nick

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    Did they do any moisture test on the concrete ? Personally i would rip it up and flash it , then put down the plastic.
     

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