Hello,

This is my first post. We plan to install a Hallmark Santos Mahogany from their Exotics collection. It is a 5 inch wide engineered plank in random lenths up to either 5 or 7 feet (may I post a link to the product, or would that be helpful?). We are installing it in our 1960's home which we just purchased (our first).

The home is built well above ground, on pillars, so the subfloor does not rest on a concrete foundation.

We plan to install (ourselves if we don't chicken out) with staples of a width recommended by a professional installer. We will not glue-down, except for using some polyeurethane adhesive (and nails to hold those boards in place for drying) in the border areas that we can't reach with the stapler machine.

We are new at this and I wanted to ask some initial questions. Highly doubt these will be my last questions. In no particular order:

1. Checking the Hallmark installation guidelines today (after purchasing and having the wood delivered), I see that warranty requires that wood subfloors be at least 3/4" inch thick. I think our subfloor is 1/2 inch (will get exact measurement, but we don't think it is 3/4"). Our neighbor has the same home and floorplan and has not yet installed wood floors, but is planning to. He said he wanted to intstall thicker subfloor first. But I found this out BEFORE I knew that our floor manufacturer required 3/4" inch wood subfloor. Thoughts? How expensive and time consuming is it to replace a subfloor, if it comes to that? Do you put new plywood over existing subfloor, or do you rip out the subfloor and have it re-installed (we'd likely need to have someone do it as we have no experience with this).

2. There is a cat urine issue on the subfloor in one of the rooms. Unfortunately the previous owner had 2-3 cats who were confined for large portions of the time to one of the bedrooms. The room stunk when we bought the house (and when we toured it beforehand). Having now removed the carpet, we find that at least three corners of the room are soaked with cat urine. The urine is dry but still has an odor and there are very obvious stains on the subfloor and even some black mold on the drywall under where the baseboards were in the most "heavily-used" corner. She had cat litter boxes in there but clearly the cats "missed" all the time. Is there a way to remove the odor from the boards or do we need to replace them? If we need to replace them, how is this done? Especially since they are in corners and the stained areas abut the walls (and it even looks like the pee got on the walls, given urine-mold on the drywall)? How is sub-floor removed when it is against a wall? Should we have it removed professionally? Is there a way to deal with it without removing it, or is that ill-advised? What about the drywall?

3. In one room, the subfloor has buckled upward at a seam, or formed a bit of a peak at the seam of the two subfloor boards. We haven't measured whether this exceeds the recommended 3/16" levelness discrepancy limit within a 10' radius established by the NWFA, but we THINK it exceeds it. How would you recommend addressing this, if it indeed needs to be leveled out?

4. There are some large knots in the subfloor. Fill with filler?
5. Some of the seams seems large-ish. What is the rule of thumb, if any, for subfloor seam width and how to you address wider than ideal seams?

6. What is the best way to remove thick adhesive from floor? There is adhesive or mastic in the entry-way where there was another layer of plywood laid down, underneath a layer of parkay tiles.

7. It is very hot and dry where we live right now. Should we still moisture test the sub floor? How?

Thanks so much,
Sara

Just wanted to update my post to say that our subfloor is 5/8" plywood on 16" spaced joists. Do you think this needs replacing? It is out of warranty, and out of NWFA compliance, but is it an issue in terms of function or quality? Is it a bad idea to lay $10K of wood flooring on top of it?

Thanks for any input, particularly on the sub-floor thickness.

As far as the cat urine, a local floor expert has suggested that a vinegar solution applied thoroughly to the area and allowed to dry, followed by a coat or two of Killz brand primer should suffice.

Thanks,
Sara

Yes, the vinegar solution will work for you, but may need several applications.
The sub-floor should be adequate, although the addition of a plywood underlay on top of the existing will greatly enhance the rigidity of the system. If you intend to lay parallel to the joists, this additional ply would not be an option, it would become a necessity.

Thank you Dennis, what thickness of additional ply would you suggest? Can you specify a couple of ply options so I can look around for costs?

Not to butt in here....1/2" CDX plywood is what I would go with.

Butt in all ya like Floorologist, we are usually on the same page anyway.

Here's a great recipe for a urine-removing solution you can make with common household items:

16 0z Hydrogen Peroxide
1 Teaspoon dishwashing liquid
1 Tablespoon Baking Soda

Mix it together, soak the affected area and leave on till dry. If there is a white residue simply sweep or vacuum it away.
You'll probably need more than 16 oz, so just double or triple the recipe. Good luck!