Foam Question: Tape seams or not

Heatmeister_2

My project got delayed but nevertheless Rehau Pex is getting laid tomorrow and concrete poured on Tuesday.

I put down 6ml poly on the dirt and 2" Yellow Certainteed Foam over it. (nice rigid stuff made for concrete over pour).

Here's my question. Should I tape my seams of the styrofoam or if I already have poly down underneath is it redundant?

If taping is recommended, What kind should be used?

Brad White_41

One of those things

that go to how absolute you are about sealing things in general. Knowing this is a lifetime installation, this is the only opportunity is how I see it, to do the best you can.

I would also say it depends on how tight your joints are in the first place. Especially at the edges too. If they are in the center of a basement floor I would be less concerned than at the edges.

If they are butt joints and you can see a gap or if you can slide a piece of card stock between them, I personally would tape them. If Tongue and Groove joints, probably not. If there are visible gaps, some low expansion urethane foam should take care of things.

Assuming all joints are reasonably tight, if you had two identical installations one taped and one not, could you tell/measure the difference? Probably not.

But I would focus on the edges and work inward from there as order of priority.

If I were to tape, I would use aluminum foil tape. Not for any reflectove properties (there will be no air space) but because it sticks very well. Second choice would be fillament type clear duct tape for the same adhesive properties.

My $0.02,

Brad

hr

Foam sheets

move around quite a bit as you walk and work on them.

I wonder how much tape would actually be there doing any good after the mesh and tube install.

hot rod

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Josh_10

Not to mention the knuckle draggers that will be in there after you...

Merv

foil under concrete...?

Forgive me if I'm wrong but wouldn't aluminum tape react
undesirably with the concrete?

Brad White_9

Good point

Maybe stick (so to speak) with clear filament duct tape.