Hardwood floor application

[anwalt]

Wife wants the carpet replaced with hardwood.  In most homes with a wood/plywood sub-floor that would not be a problem.  This house is built with      1 1/2 in concrete over 1/2 plywood.  2X4s were laid out in the outline of the walls.  Concrete poured on the sub-floor to the height of the 2X4s.  Then, the walls set on top of the 2X4s.   I am not the original owner of the house.  I see only two obvious choices:  a floating floor, or gluing the floor to the concrete.   I choose floating.  Gluing the floor to the concrete is not kind to the next owner. 

Wife wants 3/4in floor.  The thin ~5/16in 'engineered' flooring and laminate (mdf core) flooring can be purchased with a 'click' tongue & groove.  I used engineered click groove on a prior house.  I have been unable to find a 3/4in 'click' flooring. 

I did find pre-finished solid 3/4 flooring in an acceptable color. 

Now the question:  is there any reason that one could not glue the joints on 3/4 solid flooring?  (Other than the time required.)  With unfinished 3/4 flooring I have had some warped boards that needed to be persuaded to close the joints.  I would think pre-finished solid flooring would be straighter than unfinished flooring.

Comments and suggestions welcome.

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Thanks to all woodnetters who responded.  No glued solid floor for me, or my wife.  Will find suitable engineered floor. 

I do appreciate the responses and the good logic in each. 

tom

[MikeBob]

I was a General Contractor b4 retiring, I did many a total remodel with poured floors, adding 3/4"thick hard wood, but I had a sub do the install. I dont know how he did it. Call 3 hard wood flooring installers and ask them how they would do it, that is the only way you will know, unless some one here is one. Otherwise it is just opinions here and you end up with the problem if not done right. Even here you dont know what someones credentials are.
My installers may have used short staple/nails instead of glue and let it float. I doubt then spent the time and materials for all that adhesive, and I seen the floors b4 sanding  and finishing, and there was no glue residue on the top surface. How would you clamp each piece to the next till dry, that would take forever.

[KC]

Wife wants 3/4in floor.  The thin ~5/16in 'engineered' flooring and laminate (mdf core) flooring can be purchased with a 'click' tongue & groove.  I used engineered click groove on a prior house.  I have been unable to find a 3/4in 'click' flooring. 

Why is the missus hung  up on 3/4?

[tomsteve]

I have solid oak floors in my house. through the seasons I see the changes in the joints. I could only imagine what COULD happen if they were all glued together.

[jamesglenn]

I have installed hardwood flooring in my house and a few friends, but never over a gypsum base. the prefinished boards are just as warped sometimes as the unfinished, so I don't see gluing them is going to work unless you calculate a lot of waste. Not to mention the expansion of solid wood.

The floating floor is designed to minimize the expansion issues found with solid wood.

I would convince her to go with the normal floating floor, the better quality stuff can even be refinished one time.

[Kansas City Fireslayer]

I think attempting a glued floating floor with solid 3/4" hardwood would be a big disappointment. I don't see how you could expect it to maintain reasonable flatness without having each board fastened downward to the floor. I wouldn't attempt to make a floating floor that wasn't designed to be a floating floor. I think it will end up being a mess. I would stick with an engineered floating floor system.

[mad_planter]

If the boards are going to cup or lift I don't think the nails are going to stop it.  I would think think the biggest problem with gluing them together is you've created one enormous wide board with a much greater effect from cupping and expansion.

[joe1086]

LIL

Our 20 year old oak flooring moves. Not dramatically, but enough to slip a dime in some of the spaces in the winter. Solid wood flooring is going to have all kinds of boards...plain sawn, quarter sawn and rift sawn. They all move, but move at slightly different rates.

An oak board will shrink 1/16" per foot or more (in width), depending on changes in humidity. If you have a 20 foot flooring span, that totals 1 1/4 inches. Nails/staples maintain the relative positions of the boards but allow for the movement.

Gluing sounds like a bad idea to me.

[oscarMadison]

can you talk her into 1/2" or 9/16" engineered flooring? If so consider something like this . I used it over concrete and it works great. It is tongue and groove engineered flooring.

You glue the tongue and groove only. Start the first row with the tongue facing out. Put the glue in the groove, slide it over the tongue. It will swell and form a snug fit so align it right away. The first five or so rows will still be light enough to move but as you add more rows it will become heavy and quit moving. What is neat is you are basically creating one big heavy board. As a result it weighs itself down and stays in position on it's own. Mine has been down for eight years and is working well. Once it is in place it feels just like a solid wood floor instead of the sound and feel of a normal floating floor.