How to glue wood to smooth exterior concrete?

Question

I am planning to put treated wood sleepers (2x4s) over a concrete patio and attach deck boards to the sleepers. This is an exterior area which gets plenty of sun but we're in a wet climate also. I think the wood will dry OK but the concrete will retain moisture.

I will mechanically attach the wood sleepers - but I am also thinking of using adhesive in order to reduce any "bounce" and provide extra holding power.

The concrete surface is in great condition but is very smooth. (So smooth that when wet it almost feels like walking on icy pavement!)

It sounds like polyurethane construction adhesive would be a good choice - is this correct?

Do I need any type of surface preparation - like a primer - before using the adhesive?

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FYI - I am planning to use stainless fasteners because I don't trust "coated" for the long haul since they will be in moist (if not wet) concrete all the time. This is one reason to also use adhesive, because the fasteners are a little bit pricey.

Answer 1

I would always aim to "Float" the sleepers on top of the concrete floor. since concrete is always porous and will retain water (ok, your floor sounds screeded) but even still.. it will have water.
So to Float the sleepers. When you fix them to the surface. use some washers to raise the sleepers -- (if you wanted, you could get some strong rubber and make rubber washers -- however, depending on the mass of the beams, i would say you would have more sound deadening effect by adding some good quality silicon / sikaflex rubber between the sleepers and the deck boards.