Hi,

I'm sure this topic has been covered many times before, but I figure I would bring it up again to see if there's any new thoughts on it.

Anyway, I am getting ready to install 3/8" x 5" engineered hardwood floor over plywood sub floor. I can't decide whether to nail down or glue down. I'm more concerned with finish look years from now. I don't want it to buckle, tent, or gap. What method should I use?

Thanks in advance for your advice.

I just finished, placing my engineered floor as a floating floor, by gluing just the tongue and groove, I like the feel. Make sure that subfloor is flat! Just another option!

I haven't thought much about floating method with glued tongue and groove, but after some reading, I guess it's also an option. Does it sound hallow when you walk on it? I have both plywood and slab on one side of the house. My engineer wood floor is capable of all 3 types of installation. Just trying to figure out which method would be best.

Glue down will be the quietest installation. If you are in a dry area clic floors when they shrink tend to be noisy at the joints. When stapling a floor 5" or wider most mfg's require a bead of construction adhesive on the groove side for additional holding power. Even when nailed closer the amount of holding power is about half of a 2 1/4" width. Charles Peterson's book details this also. Gluing tongue and groove also acceptable that certainly will reduce gaps in winter as the floor will expand and contract as one item. Be sure you leave a gap for expansion as instructed in the mfg's instructions.

I thought that was just for solids Jim. I have yet to see an engineered manufacturers state that. But certainly could not hurt. I have a 6 inch coming up over a new ply subfloor.

If your going to glue another layer of ply would be advisable so your not gluing to the original sub floor. That way when it needs to come up your not tearing out the primary sub floor. Theres sub floors and then theres underlayment which are often confused.

I would nail it - it's the most secure installation and since you have plywood, I would nail it directly. Over time, the glue can pop up, especially if not done by a professional.

When you have solid hardwood, 5" or more, you should add in some glue/strip the floor in addition to nail, but that is not required for engineered. Engineered will expand/contract less. Make sure you still allow time for proper acclimation, even if it is engineered.

Debbie Gartner, aka The Flooring Girl

Debbie, I know solid is recommended but as for engineered thats what I was always told, but when people say that 5" and over needs glue as well, no differentiates between engineered and solid. I'm gonna read through the newer nwfa installation guidelines and check that. Not sure I've read it in any mfg's guidelines either.