I'll be installing a laminate floor over a concrete slab. The installation
instructions specify that the subfloor must be level to within 2mm (they
don't specify over what gap though).
I just spent some time trying to determine how flat my concrete slab
is by placing a piece of string really taut and then measuring the gap
between the string and the floor.
On the worst spots, the gap was a little over 2mm, perhaps 2.5mm.
Do I need to worry about this? How much is "too much"? I'm wondering if
I'd make things worse by trying to fix these depressions (just a couple
of spots in a 15' x 20' room).
If there is too much gap the planks could seperate where they snap together
or become loose as time causes them to wear from movement.
I had a similar problem over vinyl and in a few spots where the traffic was
low I doubled up the foam pad under those spots.
So far so good.
Your floor needs to be level. So what does this mean? Take a single
board, lay it across the suspect area's (make sure you put the
underpad down also) and check for bounce/deflection. if there is very
little if any at all, start installing. If you use a beter quality of
underpad ie; Quietwalk felt, it will take up these little
discrepancies. Trying to level the whole floor perfectly is a waste of
time, money, effort and resources. Laminate when combined with a good
underpad will make up for this. We install 200,000 sq/ft + per year of
laminate and our crews use this as a guide for which underpad to use.
If there are bad area's you can always use a floor patch cement,
available at most lumber stores, it sets in about 35 minutes. Note;
Because this is a basement installation, PLEASE make sure you have a
vapour barrier installed or a certified underpad that incorporates an
underpad. Cheap white foam sheets do not cut it and will void any
Cheers and Cia
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.