How to terminate a vapor barrier against a concrete slab?

[trasan]

I am going to install a vapor retarder fabric in my vacation home that I am building, and I wonder how to finish the vapor retarder against the concrete slab? From what I understand, you should not extend the vapor retarder fabric 10-20cm out onto the slab like you usually do with a vapor barrier. It states in the installation instructions for, for example, T-emballage's vapor retarder that "The product shall not be used on concrete surfaces as the alkali resistance is not evaluated."

Is there any tape that you can use to tape the vapor retarder down to the slab to make it tight at the sill? Or how should you do it?

Grateful for answers.

 

[El-Löken66]

I am going to install a vapor retarder fabric in my vacation home that I am building, and I wonder how to finish the vapor retarder against the concrete slab? From what I understand, you should not extend the vapor retarder fabric 10-20cm out onto the slab as you usually do with a vapor barrier. It states in the installation instructions on, for example, T-emballages vapor retarder that “The product should not be used on concrete surfaces as the alkali resistance has not been valued.”

Is there any tape that can be used to tape the vapor retarder down to the slab to make it tight at the sill? Or how should you do it?

Thankful for answers

Yes, there is special tape, check with the manufacturer. I don't dare to give an exact completion against the concrete, but you should be able to manage it with the tape.

 

[Pärran]

I used sealant/adhesive intended for use with the vapor barrier. According to the instructions from isover.

 

[Rickard.]

Since the sill is (should be) sealed against the concrete, I would have used double-sided seam tape along the bottom of the sill and then just cut off the excess. When it's compressed behind the panels, it's likely to be really tight. The last time I did this, I didn't bother with any of that and just cut the plastic flush with the floor as there was no reason or advantage to spending a lot of time trying to seal it 100%. Plastic pressed against a stud or, in this case, a sill is guaranteed to be sufficiently tight to fulfill its primary function.

Taping on concrete usually doesn't hold very well, and it's definitely not completely tight (but probably tight enough anyway).

 

[trasan]

Okay, I'll check with the manufacturer about what they recommend, otherwise, I'll probably go with double-sided splice tape, thanks for the answer.