35 year old subfloor

castle stone · April 18, 2007, 09:37 AM

Hi guys,

I'm preparing my parents house for a hardwood installation. There is currently a 3/4" strip flooring over the joists. The width of the subfloor is 6" x 1" thick and is installed on an angle over the joists. There is approximately 3/16" gap between the planks. Over that is particle board with vinyl on that. I'm going to remove that vinyl and particle board.

My question is, can I install the 5" black walnut 3/4" hardwood over the strip subfloor, or do I need to beef up the subfloor. I was going to put the black walnut with my hardwood stapler 2" staples and PL400 every 6-8 inches on the back of the hardwood. If I need to beef up the subfloor, what thickness would you recommend 1/4 or 3/8??? Is it okay to staple the new subfloor or does it need screwed like for tile installation???

Given the fact that I have to glue the black walnut down to the subfloor, I can't use felt or wax paper underneath. Is there a problem with anything that you see here?

Thanks a million for your thoughts,

- Curtis

Tandy Reeves · April 18, 2007, 12:33 PM

NOFMA has just recently released a technical publication "Installing NOFMA - Certified Solid Wood Flooring Directly To A Slab Using A Wood Flooring Adhesive". I will quote the last paragraph of the publication:
GLUING WOOD ON WOOD
A corollary to this directive for gluing wood flooring to a slab is the possibility of installing wood flooring directly to a wood subfloor with a full-spread, troweled adhesive. Because wood flooring adhesives are stronger than the wood fiber units, damage to the subfloor can be expected when boards must be removed.

Therefore, applications over a plywood on slab system or a conventionally framed subfloor and wood joist system should carry the following cautions:
Repair of individual board(s) will likely result in damage to the subflooring.

As the area to be repaired increases, significant subflooring damage can result.

Complete replacement of the wood flooring will likely result in the need to
replace a significant number of subfloor panels and/or necessitate modification
to the primary framing to maintain platform integrity, particularly at the walls.

Why not put down 3/4" plywood and use cleats or staples to put the floor down instead of glue?

Floorguy · April 18, 2007, 01:13 PM

For 5" you will be fine going directly over the 1x6, Just run the flooring across the joists. If the joists change direction, so will your flooring. Now, if you overlay it with at least ½" plywood, you can do anything you wish.

rgfloor · April 18, 2007, 03:20 PM

I don't know who makes this wood Tandy, but Anderson Hardwood specifically states in their install instructions that anything over 4 inch wide must have cleats or staples AND glue every 6-8 inches. I think that is what he was talking about.

Tandy Reeves · April 18, 2007, 04:46 PM

If I knew how to do the quotes thing I would pull it down. However, I was going by what was said in the last paragraph. Perhaps I misunderstood.

castle stone · April 18, 2007, 08:55 PM

I'm on the same page as RGFLOOR, that is what I have read. I don't anticipate having to repair the wood, but if I do...well, lets not go there

I am going to use a hardwood stapler, not just glue it. From what I've heard, the glue just help hold everything together in relation to the expansion issue with 5" boards. I've installed several prefinished hardwood floors, but have never worked with a) Black Walnut and b) 5" t/g planks...cross my fingers. Any tips in relation to the installation would be appreciated...