Installing Laminate Flooring Foam Underlayment
Putting down underlay is a pretty straight forward job. The most important step is to prep the subfloor before you even begin to install laminate underlayment. Done correctly it will protect the interlocking mechanisms on the flooring and increase the life of your floating floor.
Step #1: The Manufacturer's Instruction
Read It!! I know we all ignore it, but if you have trouble down the road and you've bypassed a special clause in the find print, you'll have no leg to stand on.. some laminate floors with underlayment attached are not warranted for wood subfloors.. some are ... some underlays are approved for over top of electric floor heating blankets other are not .. it is always better to know before installation!
Step #2: The Subfloor
Most laminate flooring manufacturers have a requirement that the floor must be flat within a 3/16" gap in 10'. Thus if it is a wood subfloor you may have to consider sanding off the high points if this can be done without affecting the structural integrity of the subfloor.
For concrete, it may be a matter of mixing Portland cement or equivalent floor leveling compounds to fill the valleys. Make sure to read the product instruction sheet to assure adequate drying time is allowed before flooring installation. This technique can also be used on valleys on a wood floor.
For concrete floors it may be important to follow Wilsonart's recommendation for testing moisture content in your subfloor. Most installers do have special meters for this type of test so ask where you buy your flooring. This standard is consistent across most laminated floating floor products on the market today.
"The Maximum allowable moisture emission rate for installing Wilsonart Flooring is 5 lbs/1000sq.ft/24 hours. " (Testing guidelines ASTM F 1869 test method)
Step #3: Undercut Doorways
Using a loose piece of laminate and underlayment padding as a depth gauge, cut all your door jambs and casing up off the floor to allow the floating floor to move underneath. Remove all the baseboard.
Once you are comfortable knowing that the floor is within the acceptable standards for flatness, and the mouldings have been undercut to the correct height, clean the surface to remove any debris that may affect the laminate floor from sitting directly onto the surface. You can then begin putting down underlay padding.
Step #4: Install Laminate Underlayment
If your floor is over concrete the first job is to lay a polyethylene film down, then the first row of foam underlayment. (As discussed earlier this could be accomplished by using a 2-in-1 product that combines vapour barrier and foam in one product.)
Start in the corner where you intend to begin the floor and run it tight up to the wall. Only roll out one strip of underlayment at a time. Then begin installing your flooring. When you get close to the edge of your underlay start a new row, overlapping the plastic vapour barrier 8-10" and butting the foam up tight together (NOT overlapping). Use plastic or foil tape to hold the edges of the foam in place.
If you need a vapour barrier and you are using a 2-in-1 product that does not include an overlap, tape continuously from one end of the strip to the end, to seal the entire seam. Where the underlayment has a overlap it is only necessary to tape intermittently to hold it in place until it is covered by flooring.
Continue across the room. Use a pocket knife to trim the foam when you reach the far wall...
Installing laminate flooring foam underlayment is a pretty easy job with the critical issue revolving around proper subfloor preparation and taping the foam so that it doesn't slip in the installation process.
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