Question: We are project/construction managers based in China. A client has asked us to assist them complete a private members club (construction stopped over one year ago due to contract disputes). Much of the work has been completed, including the subfloors and approximately 45% of the imported hardwood floor system (South American wood, I believe). I have several concerns: 1. There is a large ballroom with hardwood floors. The base substrate is concrete, with wood battens and then 9mm standard plywood on top. The imported hardwood boards (parquet type) has been glued (glue material not know) to the plywood. The hardwood floor boards are 25mm thick, approximately 75mm wide, and unfinished. 2. I am not convinced the 9mm standard plywood is sufficient for a long lasting ballroom dance floor. What type of subfloor do you recommend? 3. I am concerned about the type of glue that may have been used. What type of glue (or nailing?) to you recommend in this situation? 4. Central coastal China has extremely high humidity in the summer, and though this club facility will be airconditioned, I am concerned about checking and shrinkage. Most of the hardwood floor materials have been sitting in a basement level for at least 1-2 years in high humidity. Should the hardwood floor strips be installed as they are now, or should they be stored in an air conditioned environment that approximates the club’s future conditions? Any advise and help is greatly appreciated. Yours sincerely, James R. Smith Answer: Dear James You have many reasons to be concerned. First the plywood sub floor is much too thin too provide any long lasting support. It should be at least 18mm and in a tongue and grove configuration on it’s edges so that there are no weak areas. Glue for parquet in such a hard used area should always be a rubber based mastic. Here in North America a popular brand is Dri-Tac ® made in New York.Their phone number is 718-497-5462, they may be able to provide you a local supplier. You can tell a rubber based glue by it’s tan colour and flexability. The directions on the label will tell you to spread the material and then let it flash off for about one half hour. This glue works so well I have had my completed jobs go through 3 accidental floods and the laminated floor only sustained partial damage on the third flood. The floor was a laminated 5 ply aok plank and is a very durable and stable material, being plywood it will not shrink or expand and is the only type of wood floor that should be inslalled below grade. You can get these floors with special commercial duty finishes already on them. You will have to get yourself an electronic moisture meter and certainly get that wood out of the basement now. No flooring material should be installed until it’s miosture content is about the same as the subfloor’s. And in an air conditioned environment it will eventually go down to 6-8%. Don’t install that floor until it does or it will shrink the rest of the way on its own leaving gaps all over. There is one more issue, just what is the species of wood you’re using? Some of the South American hardwood imbuya wood and many others have such a high oil content in them they will eventually reject any finish you put on them, and may also reject the glue it’s held with. Do some research and find out what this material is and it’s suitability for flooring. If you found this information helpful, please explore the Wood Floor Doctor.com by visiting the rest of our website. As always your Most humble servant, Joseph, the Wood Floor Doctor.

Question: Would you tell me more about ivory wood and grapia wood? Thank you! Carol Answer: Dear Carol Grapia is botanically named Apuleia leiocarpa and Apoleya leiocarpa, and several others. It is grown in South America. And that’s all I know right now. Ivorywood is grown in Argentina, Paraguay and Brazil, and is also called Marfin, Pau Liso, and Guantambu. It’s a medium sized tree never more than 8 feet. Ivorywood is nearly white or pale yellow-brown, with little grain contrast. Mostly straight grain, with a fine even texture, and no distinctive odor. It is fairly dense from .65 to .73 depending on where it’s grown (only a little less dense than oak). It is non resinous so it should finish quite well. And sanding should not be too difficult, as this wood is not over hard. A good substitute for maple or birch.

Question: Our new wood floors in a below ground level basement are warping due to water that I can actually hear underneath. I don’t know where to begin in handling the situation. Do you think a floor person will be knowledgeable on how to handle it? I’m hoping the building’s insurance will cover the repair. Is this something you’d consider structural? Answer: Dear Michelle Sorry to hear of your troubles. But the new wood floor should not have been installed below grade in the first place. You didn’t say if this was a laminated (engineered hardwood plywood) or solid wood floor. In either case a below grade application for these products is ill advised. I’m not sure who advised you to install the wood floor in the basement, but they have contravened industry standards. You best bet is to remove all of the wood floor. And don’t ever bother installing it again, unless you want to repeat this dilemma. Then have a basement water proofing contractor take a look at your problems. Take a look at the article on hiring contractors available in the search box at the top of this web page. It will give you some clues to finding honest people. You may or may not have an insurance claim, on the water damage. If only the wood floor was wrecked, they may say this was an improper material installed in such a water prone area. They would be correct, but don’t volunteer the information. If you actually hear water running under the floor, it may be a leak from a pipe, if you are lucky. But it may be something more sinister like an underground spring that your house was built on. You didn’t say if this was a new home. If it is you may have a claim against the new home warranty. But a qualified basement water proofing expert should be able to determine the cause.

Question: My hardwood floor had carpeting put down on top of it. The carpet is removed but the floor has nail holes around the edge from the tack strip. Is it possible to fix this as part of a floor refinish. How? Answer: Dear Larry Fill the holes a day before you intend to sand the floor (you did say you were going to SAND and refinish). Choose a colored latex filler, just a shade darker than final color of the finished floor. Elmer’s make such a filler, sold as most hardware stores in small tubes (the size of toothpaste tubes). When you sand the floor the excess will sand off and leave the hole neatly filled. If you found this information helpful, please explore the Wood Floor Doctor.com by visiting the rest of our website. As always your Most humble servant, Joseph, the Wood Floor Doctor.

Question: We recently had the wood flooring in our home refinished after finding under carpet when remodeling. The floor, finished about 8 weeks ago, is beginning to look splotchy and uneven in color and I have been told that the finish is probably delaminating. The floor was sealed with a solvent based sealer followed by two coats of water based finish applied on consecutive days. I have found that the solvent based sealer is compatible with the water based finish but there is a time period of approximately 30 days for curing the sealer. My flooring contractor assures me that the finsihes were totally compatible. What do you think? Answer: Dear Julie The simple test for finish adhesion, is to wait until the finish has fully cured. In the case of water based this will be 2-4 weeks. Choose a inconspicuous area, or an area that you suspect is de-laminating. Cross hatch (the tic-tac-toe pattern) a small 4 square inch area with a razor blade. Cut right down to the wood. Apply duct tape to the test and rip it off. If some finish comes off, but most remains, you are probably OK. But if it most or all comes off the floor will need to be sanded again. More coats on top of this won’t help. There is a tendency now to apply fast dry oil based finished before the water based finish. This is to avoid the grain rising on the first coat of water based. This is a fairly new development, and it may not work in all cases. Generally speaking you don’t have to wait the full 30 days between coats, but in most cased 24-48 hours should be sufficient. And of course the sealer needs to be scuff sanded (screened). Some of the more prominent water based finish companies are offering this, and if he is using say, Bona Kemi’s products, and following their directions to the letter. You and he may have a claim against this company for misleading instructions. They will supply at least replacement material. But on the other hand if your contractor used different makers of finish, they may well not be compatible, and re-sanding will be the only option. I personally stick to the same type of finish for all coats, it makes for easier touch-ups and re-coats later. As always your Most humble servant, Joseph, the Wood Floor Doctor.

Question: We went away for the weekend this holiday season and came back to discover that our Christmas tree stand had a crack in the bottom. Although we had a vinyl cloth under it the water spread out to the wood floor. We now have several strips of our red oak stained floor that are warped and curling. We tried laying boards and weights on them when they were still damp, but it didn’t seem to help. Any ideas? Answer: Dear Robyn For now, it’s best to let the wood dry out on it’s own. You can put a fan on the surface (but not a heater). Keep the wood floor uncovered. If you can access the underside you can heat this area just a little (80F) to dry out the subfloor. Be patient and wait about a month to see if the wood is settling back into place. In most cases the winter heating season with further dry out the wood. If you don’t want to repair the floor right now wait until the floor and the subfloor have a moisture content of 6-9%. Moisture meters are available at http://www.leevalley.com. Order number 99N15.01. Or you might borrow one from a local carpenter or cabinet-maker. It may be worth removing just one board to speed up this process. Choose the most warped board, and remove it according to the directions laid out in my repair article available in the search box at the top of this web page. Or you can remove all the warped boards, check the moisture content in the spot, and repair with new wood right away. Once the floor has dried out, and settled back after at least a month or even two, repair the boards that have really warped beyond recovery, and sand the rest flat. You will need to use a floor edger sander with 80 grit sandpaper, and finish off with a vibrator sander with 100 grit, then hand sand again with 100 grit until very smooth. Touching up the stain will be tricky, be sure you use the same brand that was used on the floor. You didn’t say if this was a prefinished floor, and if so you may obtain a touch up kit form the manufacturer. But if it’s a site finished floor, and you want further instructions on staining and touching up let me know.

Question: Can a wood floor be installed directly over an old ceramic tile floor? The existing floor is bonded to a wood subfloor. -Gary Answer: Dear Gary I should say not. There are few adhesives that will stick well to ceramic tile, and the ceramic grout may crack in the future making an in accessible problem with the wood floor. Best to remove the ceramic, make sure you have a suitable wood subfloor (read the article about strip and plank available in the search box at the top of this web page) and nail down a strip floor instead.

Question: I have recently installed a wide-plank pine hardwood floor in my bathroom. My contractor told me to sand, seal, and then polyurethane it. I sanded and sealed with a “sand n’ sealer.” After re-reading the label for the sealer, I noticed that it said that polyurethane should not be applied on top of it. I am wondering what my options are now. Will polyurethane react badly if applied? SHould I re-sand and start over? Or is it simply easier to use a different finish, and in that case, what finish should I use that will be water-resistant and easy to clean? Is wax ok? Please let me know. Thanks, Ines Answer: Dear Ines I’m really afraid your contractor has made a fatal error, you should not have a solid wood floor in the bath area, and the wide pine plank is just about the worst choice he could have made for you. Wood in damp and wet areas, no matter how many coats of finish are applied will get water damaged. Water molecules are like little octopi, they will slither past the smallest seam, swell the wood and lift the finish, and invite more of their kind in. That all said, if this wood is more that 4″ wide you should also have followed the instructions on Plank floor installation, as outlined in the Hardwood Authority section of this site. Please read this. But, I bet by now you are possibly mad at me for suggesting this worst case, and asking for a donation to boot. I cannot help that, I just call them like I see them. So now that I have warned you of the improper installation, and you still want to go ahead and finish the floor, you guessed it, you have to remove all the Sanding Sealer. This is not the correct first coat for an oil modified polyurethane, and any poly on this wil peel off. This is doubly critical in your case, since you have installed the wood in such a wet area. So sand the wood to the bare surface, removing all traces of that sealer. And then brush on 5 coats of an oil modified polyurethane, preparing well between coats for maximum adhesion. Read my article on this subject. Oh, wax is the worst thing to use in such an area, it will simply not hold back the water, and will whiten every time it gets wet. And don’t wax it in the mean time, it will interfere with the sanding AND the finishing with the proper oil modified polyurethane. As always your Most humble servant, Joseph, the Wood Floor Doctor.