I am a wood flooring instructor

I have been in the wood flooring industry for over 40 years and currently help do it yourselfers get professional results on their wood floor projects. I learned the trade with a company that refinished gym floors during the summer and did wood floors in custom houses the rest of the year. I have worked in the flooring departments of Home Depot and Lowe's as well as several wood flooring companies as an installer and refinisher.

Welcome to the site.
We see more people installing wood over concrete now. What questions should a salesperson ask before making the sale.

nealtw said:

Welcome to the site.
We see more people installing wood over concrete now. What questions should a salesperson ask before making the sale.

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The first questions you should ask concern height tolerances.

To install nail down 3/4 inch solid, a sub-floor needs to be installed to nail to.

I prefer in a residential install to put down a thin layer of foam as is used for a floating laminate floor. Over this I lay 4 by 8 sheets of 3/8th's inch plywood parallel to the walls and staggered so the seams don't match up. I then add a second layer 45 degrees to the walls which is also staggered. I then use 5/8 inch pin nails with my brad air nailer and generously nail these two layers together.

The result is a 3/4 inch plywood sub-floor the size of the room which is floating.

Using short staples or cleats I can then any solid wood floor of my choice.

The problem with this is the inch and a half gain in thickness. You need to ask about door clearances, and transition problems which may or may not be able to be resolved with this thickness. Also the added thickness may cause issues with the dishwasher, free standing range and space over the refrigerator.

If there is not a way to resolve it you may have to go with a floating click together, a glue down engineered floor or a glue down parquet.

Moisture in the concrete is also another issue that you need to ask about.

I've seen some awful messes with wood over concrete and I haven't seen your suggestion before. It sounds good, I would add glue between the plywood layers as I'm not sure I would trust just the pin nails. How unevan is the floor before you say can't be done or has to be leveled.
I will be looking for others to bring there thoughts.

nealtw said:

I've seen some awful messes with wood over concrete and I haven't seen your suggestion before. It sounds good, I would add glue between the plywood layers as I'm not sure I would trust just the pin nails. How unevan is the floor before you say can't be done or has to be leveled.
I will be looking for others to bring there thoughts.

Click to expand...

Neal you are right about the pin nails. They are just to hold the layers together while it is installed. Once you install a wood floor with a Bostich stapler or with cleats the short flooring staples or cleats will be holding the two layers together in addition to the pin nails.

This technique of the two layers of plywood is one used for installing gym floors except with gyms it is two layers of half inch plywood.