best glue for concrete

[herd]

I am going to raise the floor level of a concrete deck on an addon that I am doing to my den. I intend to use 2x4's flat and then upright. I want to glue the flat 2x4's as well as fasten with 3/8 tapcons and some ramsets. What is the best construction adhesives to use on this, would Liquid Nails HD do the job or is there a better adhesive?

If it was wood-to-wood, I wouldn't hesitate to use Liquid Nails but am not familar with its ability to bond to concrete. I know Loctite has a HD construction adhesive that is rated high but I have no exp with it. tks.

 

[Shirleyshusband]

I've done exactly what you are doing several times and never had a callback/problem.

 

[JB4310]

Since it's not a critical application almost anything you put in there will suffice. But since nothing permanently bonds to concrete, it's more of a gap filler/cushion, to stop creaking, you're trying to achieve.

Liquid nails can get hard and brittle, I would recommend something more flexi, even a silicone caulk, not the adhesion of the LN, but your screws are going to be doing all the holding anyway.

Even that stuff they put on the top of foundations before they put the sills on, it's a rolled foam insulation.

Use the LN from there up, but IMO maybe not the best for the bottom.

JB.

 

[/pine]

Did you consider roofing cement?
it does not cure nearly as fast as more profound adhesives but it will eventually cure as a cement and it bonds well to to both treated or non-treated wood and concrete.

 

[radioman]

Did you consider roofing cement?
it does not cure nearly as fast as more profound adhesives but it will eventually cure as a cement and it bonds well to to both treated or non-treated wood and concrete.

good point. most treated stuff fresh from the store is pretty wet, hard to glue with. I assume you going to use treated boards on concrete ?

 

[herd]

I did not think about roofing tar/cement, but I will now as what you say makes alot of sense. I will be using treated wood, "yellow wood" in fact, it is not usually as wet as regular treated and supposedly not as corrosive to your fasteners.

tks for the idea

 

[JB4310]

I don't think roof cement is a good idea, and this is coming from someone who has made a career out of using roof cement, do alot of roof repair with nothing more than a trowel and a pail of "tar".

It will stick to the concrete as good as anything else, but it never really "sets up" like a caulk or adhesive, so you will not get any adhesive strength, more like a contact hold. Eventually it will get hard, but as designed, that ability to stay soft is what's needed for roof repair, preventing re-cracking where the material bridges over cracks and holes in the roof surface.

For that same reason it would not make a good cushion like a caulk or foam, since it isn't designed to set cure like adhesives and caulk, it just skins over. During initial install it would just squash out as you tightened the fasteners and would not retain any cushioning characteristic, and if it got warm enough in there it could settle and level out, making it not even a good gap filler.

Again, since it's not a critical app I doubt you would notice the difference between any way you chose to do it. But the roof cement might be the messiest, I would think a good quality soft foam insulation might be best, not one that you spray out of a can but something on a roll.

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I have seen problems with putting wood floors over slabs, where moisture and humidity were an issue.
A plastic vapor barrier over the top of the slab would probably help.

JB.

 

[forgeblast]

you can check for moisture coming out of the cement by taping a plastic bag on the floor and leaving it there over night. then you can check to see if its dry or wet.

 

[6sunset6]

I would think moisture coming out would vary with the season.
I would put down a vapor barrier. If you put it under the 2 x 4 that pretty much eliminates glue. You could put it over which would be ok .
I think roof cement would never stop out gassing and you would smell it forever inside. Urethane caulk sticks to masondry and wood and although not a structural adhesive , not to bad. Comes in tubes and a little hard to find . Home D does not have it Lowes does. Little stiff in the tube .

 

[TheRegMan]

PL is the absolute best adhesive I have ever used. I used liquid nails until I was putting some marble tiles up and it would not hold the tiles vertically. I went back to Lowes and decided to try the PL. That is all I'll use for anything anymore.