Before rolling out the underlayment be sure to sweep vacuum and remove all debris on the substructure.
How to lay vapor barrier on concrete under laminate flooring.
The best way to install the vapor barrier is put it down before you put any laminate flooring down and what i m going to do is i m going to go ahead and cut a piece of tape so that way i can put.
If your concrete passes the moisture test then plastic sheeting at least 6 mils thick will prevent moisture from getting into your laminate flooring.
This 3 in 1 underlayment can be used under any laminate flooring to allow your floor to float and create a moisture barrier.
Where plastic sheets must be joined overlap the sheets by several inches and use strong vinyl tape to secure them.
Install a plastic vapor barrier.
How to install vapor barrier on concrete floor under laminate flooring.