Laminate installation questions

[khny83]

Hello all. I found some useful information on this board and figured I would ask some of my own questions. I am in the process of installing laminate flooring in my living room. I just ripped up old parque flooring that was glued down to a thin piece of underlayment. That thin piece of underlayment was nailed down to a plank subfloor which runs horizontal to the floor joists. Here are some questions that I have. The plank subfloor is pretty solid and fairly even throughout the room. Should I install a thin, 1/4" or so, plywood underlayment over the planks or would installing the laminate over the planks be fine? If I install the laminate over the planks should I install the parallel with the planks or horizontal with the planks? If I were to put down a thin underlayment what type of nails should I use and should I leave a small gap between the boards for expansion then fill it with flooring cement? Thank you for your help.

[Jerry Thomas]

If it were me I would use the plywood underlayment. I think it would give you a better surface and even everything out better. You do leave about an 1/8" gap but don't fill it with anything. Underlayments can be stapled, nailed or screwed down about every 6-8" OC for your purpose.

How thick is your subflooring and are the joist 16" OC?

[Bradley Bitter]

well first lets address the planks what kind of shape are they in? will a 1/4" underlay create a sound floor those of us who have installed a lot of the stuff know that laminate is pretty tolerant but we don't want movement in those joints. also im not sure what part of the country your in but here its hard to find a good multi/ultra-ply right now so 1/4" treated plywood sanded on one side would work great. at the seams 1/16" or so is fine the edges leave about an 1/8" . as for nailing how big is the area? are you going to burn your arm off trying to use 1 1/4" underlayment nails (and make sure they are not drywall ring-shanks) if thats the case we use 2" laminated staples in a pneumatic gun

[kwfloors]

Depending on what you have there for planks would help in determining if you need ulay or some prep. What other areas are you butting the laminate to? Maybe you need to flatten the floor with ulay in which case I might use 1/2" ulay and less nails. Was there a reason why you didn't go over the floor you pulled out? Why would a little movement in the ulay cause much of a problem in a laminate floor over the top if it is not glued or nailed to it and floating? If the floor is flat your good to go.