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Hardwood over concrete

3397 Views 11 Replies 8 Participants Last post by  Kent Whitten
What is a good rule of thumb to calculate extra for hardwood over concrete? I will be glueing down two layers of asphalt and ramset 3/4 ply. Then hardwood. normally i would charge 2-3 for install so...
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I willl go first
Tree fiddy
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your installation method may not be the best; maybe a better idea to install 2x4PT sleepers for nailing the flooring onto.
I'm not too familiar with that method i am open to suggestions though maybe you could give me a better idea on how that works? the problem is that the existing kitchen floor is hardwood over 3/4 ply and i need to matchup to it.

your installation method may not be the best; maybe a better idea to install 2x4PT sleepers for nailing the flooring onto.
Basically the sleeper method is to insulate the floor i am assuming? Yea that def would be the way to go if i didnt have to match up to existing flooring, the concrete is on grade so i dont think there will be a significant moisture problem, the HW that is already down has been there for 4+ years now and it seems to be fine, no cupping no gapping and no discoloration so i think the two layers of asphalt and a layer of poly over the plywood and under the hardwood is a pretty good insurance policy, yea? Or maybe i will Red guard (paint on waterproofing) the concrete and two layers of asphalt then just paper over the ply....Im sure there are some great ideas that all will work just as well, i guess i need to figure what the time and materials involved is and then add to my install price.
If the slab is dry and shows no signs of moisture problems you should be able to install a good engineered wood floor. Follow mfg. instructions.
Make sure the client understands the risks of installing wood floors at or below grade and have them sign a waiver.
I wouldn't try to install "real" hardwood over ply or sleepers though.
Installing wood over concrete

What kind of floor? Solid 3/4" oak? Engineered wood laminate?
One kind you can glue directly to the concrete. Solid, you need to install a plywood underlayment. Ramset 3/4" plywood. Use a lot of construction adhesive. Beads every 4". Then nail your strip floor down. This is only for dry concrete! If you have a concrete floor with moisture, you will have to use a vapor barrier.
...If you have a concrete floor you will have to use a vapor barrier.
Fixed.
Thanks casemill, after extensive research 3/4 ply is the way im going. I have not tested the moisture content yet but the concrete is over 50 years old on grade so it should be good. I would like to put a vapor barrier down any way for some extra insurance, i was told to use cutback adhesive for the felt paper, but cut back adhesive is hard to find, what do you have for a suggestion on a adhesive to lay the paper that is a decent moisture barrier in itself as well?
Thanks casemill, after extensive research 3/4 ply is the way im going. I have not tested the moisture content yet but the concrete is over 50 years old on grade so it should be good. I would like to put a vapor barrier down any way for some extra insurance, i was told to use cutback adhesive for the felt paper, but cut back adhesive is hard to find, what do you have for a suggestion on a adhesive to lay the paper that is a decent moisture barrier in itself as well?



Your in WAY over your head!!

Solid over concrete, is not to be played around with, guessing what will work.

So far you have got one good suggestion.

I will say, felt and asphalt mastic, is not a moisture barrier with enough of a perm rating. If you put down a moisture barrier(plastic) what good is it going to do, when you poke 32 holes in it, per 4x8 sheet of plywood, you put down and anchor?

The 50 year old slab... "should be OK" LOL!!!! that is going to be the one that is going to go belly up as they had no requirement for a moisture barrier under the pour, so ground moisture is going to really be at play, not just what is suspended withing the concrete.

Making a plywood sandwich, as you described, is going to cause the plywood to dry rot. The plastic goes under the plywood, not between it and the wood flooring.

Like I said, "Your in WAY over your head" How deep are your pockets, again??? I see some expensive firewood, in your near future.:eek:
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Strip floor over concrete

Thanks casemill, after extensive research 3/4 ply is the way im going. I have not tested the moisture content yet but the concrete is over 50 years old on grade so it should be good. I would like to put a vapor barrier down any way for some extra insurance, i was told to use cutback adhesive for the felt paper, but cut back adhesive is hard to find, what do you have for a suggestion on a adhesive to lay the paper that is a decent moisture barrier in itself as well?
Here is an article from FCI about this subject.
fcimag.com/Articles/Cover_Story/52e45cf87c0d8010VgnVCM100000f932a8c0____
I've looked on the internet and it seems that cut-back flooring adhesive isn't made anymore. It's been a long time since I used it myself. So I guess, get some roofing cement, which is the same as cut-back(Cold Asphalt mastic), just a little thicker. I'm sure you can roll it with a paint roller or trowel it. Then unroll your felt paper into it and roll the felt paper with a -- you guessed it -- roller. :laughing: The FCI article recommends applying the cutback to the top of the paper before putting the plywood on it. That sounds fine and maybe cheaper than using construction adhesive. Plus it's one more layer of moisture barrier. Then fasten the plywood down and put your floor on it. That sounds like a plan, right?
Thanks casemill, after extensive research 3/4 ply is the way im going. I have not tested the moisture content yet but the concrete is over 50 years old on grade so it should be good. I would like to put a vapor barrier down any way for some extra insurance, i was told to use cutback adhesive for the felt paper, but cut back adhesive is hard to find, what do you have for a suggestion on a adhesive to lay the paper that is a decent moisture barrier in itself as well?


So next time call a professional to install your floor Holmes!
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