Just purchased a house with about 600 sq/ft of engineered wood flooring on the main level. The hardwood top layer appears to be about 1/16th in. thick. All of the flooring is slightly cupped. Not terrible, but obvious. The floor is in otherwise decent shape, with a few small worn areas and only a few scratches caused by furniture. About half the floor sits on concrete slab, the other half is part of a recent addition and sits over the basement. The cupping is worse over the slab. The house is in the watershed area of Delaware County, NY so there is a lot of moisture in the soil. I would like to improve the appearance of the floor, and would appreciate any and all advise as to what my options are.

- What are the best ways to bring some luster back to the floor?
- Can I screen a mildly cupped floor?
- Can the cupping be reduced by careful sanding?
- For simple polishing, if screening/sanding is not possible, what are the best products to use?
- Purchased the Bona urethane polish, but am hesitant after reading the reviews. Thoughts?

Thanks very much in advance.

Lino

Well I think you should figure out why it's cupping first and see if you can eliminate some of the cupping. And at 1/16 I think you would go through the veneer on top to the core plys very easily on the raised edges.

Thanks. The cupping is not recent, and doesn't change appreciably season to season. So, I think it's there to stay. I have little doubt that it was caused by excessive ambient humidity and in the concrete slab from very moist soil. Landscaping measures have been taken that should improve matters. At this point, I want to improve the appearance of the floor until I replace the floor in a few years. I welcome suggestions.

Is your rh low in the house? That can cause cupping. I'd at least wait until the rh goes up and the floor should flatten out some if is dry in there now.

It is dry in there now. Rh is low. Thanks

You can try using the Bona but follow the instructions as far as cleaning and prepping the floor first. You wont be able to sand as was already stated with only 1/6 wear layer you will go through it, even screening will probably do the same as all the weight of the buffer will be on the high spots. You best bet is to live with it until you can replace it with a better material.

Thanks Jeff, you're probably right. Now, not being opposed to serious elbow grease, what about hand sanding the floor to take a new polyurethane finish, even if cupping remains as is?

That's about all you can do in your situation.You'll need to hand buff the floor and then re coat carefully.Use 220 grit abrasive paper to do the scuffing.You can do this by hand or maybe use a soft foam pad or a contoured pad/block that happens to fit the cupped shape of your boards.When scuffing the boards, let the paper do the work and try not to push hard.Just take your time.

When you have cleaned up the boards and scuffed them sufficiently, vacuum and tack the floor thoroughly and it will be ready to accept new finish.I recommend putting on a light coat of whatever urethane you prefer.A heavy coat is guaranteed to puddle into the center of each board and look bad. A very thin coat is the only solution for that as it will set up quickly.Because you have to apply a thin coat, it might be best to simply hand brush the whole floor with your favorite type of paint brush.I use Purdy China Bristle brushes of varying widths.

Thank you, Paul; fantastic information and advise. By "tacking" do you mean wiping down the floor with wet towels/rags after buffing and vacuuming? Thanks again.

Yes.If you plan to use an oil based poly, then you can tack wit ha clean rag and mineral spirits/paint thinner .If you plan to use water based poly, tack with a clean rag that is lightly dampened with clean water.

The vacuum I use does an excellent job along with the felt equipped wand so I don't have to do much tacking but most consumer vacs don't do a good job and tacking is much more important.

Got it! Thanks again for the advise.