Laminate Installation

[mikeyd]

Hi everyone,

Now that my fireplace project is just about complete (almost finished refacing - will post pics of the entire job in the Hearth Room Forum) I am moving on the next challenge before summer kicks into high gear. I'd like to lay some laminate in the lower level of our place however I'm stumped as to whether or not I need a moisture barrier on the subfloor. The laminate flooring I have is a 15.8 mm thick plank which includes a foam backer. The RH in this room can reach 70% on certain days, as it's lakefront, and the entire suface of the subfloor below is open to a crawlspace about 4 or 5 high & the entire length of the room. I've layed laminate before on a concrete subfloor which is a no brainer for a moisture barrier and I know typically at grade on a plywood SF you don't need a barrier but this I would assume is considered below grade ???

I found some info on this site that suggests no moisture barrier on a plywood SF.

"In cases where the subfloor it is a traditional above grade plywood or OSB, underlayment should NOT include a vapour barrier. Wood is a biological species that likes to breath. The polyethylene films can lock in moisture and lead to mould in severe case... thus not necessary so don't use it! "

http://www.woodsthebest.com/Flooring/underlay/bestUnderlayForLaminate.htm

Will the inherent foam backer be enough in this case ?

TIA

 

[woodsman23]

No moisture needed. Is there one under the crawl space if not then i'd pout one there. The backing is all that's needed. The floor is wood right not concrete??. If it's concrete then yes you need a moisture barrier...

 

[mikeyd]

The subfloor is wood - correct. There is 6mm plastic liner under the crawlspace on the dirt but other than that there is nothing else. I'd like to in the future put some foundation membrane on the ground and taper it up to the foundation walls to totally separate the building.