Question: On Bob Villa’s show “Home Again” that aired during the ‘tips’ section, Bob told about a wood floor that was made up of 4″ slices of pine (about 3 1/2″ square and about 3/4″ thick) and were installed much like ceramic tiles, with mastic and grouted. I’m interested in installing that type of floor in a remodelling project and would like to know more about the process. Can you help me? Thanks! Answer: Dear Lynn I really hate to say this but I have watched Bob for years, and any time he gets into the wood floor work, his products and methods have always been less than sound. I think I remember seeing this episode and know of the floor contractor who did it. The grout he used was a finish added to sawdust. I’m quite sure this stuff will dry out and crack out over time. I wouldn’t try it, unless you find someone who has had the floor down for at least 5 years. I knew something was wrong when I saw he was using only an oil finish to seal this type of floor. If these pieces move around seasonally, due to the poor finish, they will further crack the grout.

Question: We have 3/4″ Brazilian cherry floors which were installed unfinished and then sanded and sealed with Duraseal (by a floor contractor not by us). We requested the Duraseal because we do not like the look or feel of polyurethane and we have loved the way the floors look and feel. But in hindsight this may not have been a practical solution because we have 5 indoor kitties and 1 indoor dog. The little dog did had one big accident which has left a lighter stain on the floor but the biggest problem has been kitty barf. We must have 30 little stains in one or two of the rooms due to kitty barf which leaves dark stains or lighter stains (perhaps the color of the stain has to do with the PH of the vomit, I don’t know). We were intending to re-treat the floor with Duraseal Renovator which is recommended by the manufacturer but we need some advice before we do that. Is there a way to remove those light and dark stains from the wood itself without re-sanding the whole floor? The floor itself has also gotten over all very dark. We live in a house with a bazillion windows near Savannah, GA, so we get LOTS of natural light. Instead of using the Duraseal Renovator is there another product besides polyurethane that will slow the floors from darkening and would repel the kitty barf too and still have the natural wood feel that we like? If it’s best to re-sand the floors entirely we would like to know at this point before we put on the Renovator. Thanks for your help!! Charmaine Answer: Dear Charmaine I’m going to assume that when you say Duraseal you mean you applied the DURA SEAL Penetrating Finish (Stain) in the neutral color 210. I’ve had some past experience with this material, and have long ago come to the conclusion that’s it’s not really suitable for hardwood floors. And the Renovator product gave us much less than stellar results when trying to renew one of these oil/varnish floor finishes. Oil/varnishes are a newer version of the old China oil (tung) finish that was commonly used at the early part of the last century. Tung oil took over a month to cure so was supplanted by a faster drying oil/varnish like you have used. These in turn were supplanted by oil modified polyurethane and alkyd vanishes by the 1930’s. The supposed advantage of oil/varnishes is that they are repairable. And seeing how the film build on the floor is almost negligible, that would be important. You see with only 2 coats of the DURA SEAL Penetrating Finish (Stain) you have only built a protective film on the floor equal to one diluted coat of oil modified polyurethane finish. That why you can still feel and see the texture of the wood. It may look nice, but it has little or no water resistance, and that’s what counts on wood floors. Animal feces and urine stain the wood dark and the vomit like you said can actually bleach or stain the wood light or dark. I’m guessing that this is an alkaline/acidity effect, but I really don’t know my biochemistry. But bleaching is the key to removing the stains. Wood bleaches will only work when the wood is free from all finishes and waxes. I sure hope you haven’t used that renovator stuff yet. If you have you will need to remove it first with steel wood and paint thinner. Then hand sand off the finish. While you are sanding the finish off, this will give you a chance to see how deep the stain is. If you are really lucky you can sand enough wood off so that most if not all of the stain out. Use 80 grit sandpaper, and finish with 100-120 grit. I will usually use a wood scraper for the initial removal, but will always finish up with hand sanding anyway. But you will have to learn how to sharpen a scraper to razor fineness before you use it on your smooth floor. That’s another subject for another time. Use sandpaper if you cannot sharpen a wood scraper well. Hand sanding just takes a little more time, but does the same job. For any urine and feces stains that are dark, your only hope is to use hydrogen peroxide and sodium hydroxide, in a very strong and dangerous concentration ( 27% ). Klean-Srtip is one of these products that’s readily available in North America, and comes with good instructions. Visit their web site at http://www.kleanstrip.com/ for info on how to use this stuff. Oh, I just discovered that their web site is down for repairs, so you will have to call them to find a distributor of Klean Strip in your area. When their web site is working, click on the product button, then the wood bleach link. You generally have to mix the two parts of these bleaches together, but this contains it own neutralizer, so only a washing up with water may be needed after. This type of bleach will always turn the dark spots to an off white color, which you will then have to blend in with a dark colored wood stain to match the color of your finished wood floor. Bleaches are water based, so they will raise the grain and make the wood rough. Be sure to let the wet wood dry overnight. And do be careful when you sand it smooth the next day, so as not to sand out the bleached effect. Do the final sanding with just a little pressure and use 120 grit sandpaper, just until the wood is smooth. Once the dark spot has been turned into an off white spot, you will need to re-stain the spot to match the tone of the Brazilian Cherry. You might just use the same Penetrating Finish made by Dura Seal but this time choose a darker colored stain. You could also try the DURA SEAL Fast Dry Wood Stain. They both come in a wide variety of deep and dark tones, so choose one just a bit darker than your floor. If it happens to turn the floor too dark you can always wipe it off more than usual, or use a bit of thinner to help wipe or simply dilute it. You may find that you have to apply it and let it sit for some time before the color sets in a wood as dense a Brazilian Cherry. Of course just try all this on one or two spots in an inconspicuous area. Now as to the white bleached cat vomit areas, I would suggest you neutralize them first with a little vinegar, and a wash with a small amount of water. Oh, I forgot to mention that all these bleaches and washings will really harm the surrounding oil/varnish, it’s not very water resistant so use water sparingly and carefully. So anyway, neutralize the white vomit areas, let dry overnight, and fine sand the area (120 grit). Then just stain these spots with the Dura Seal stain, and hope for the best. You can use an artists brush to control the stain better. And even try those touch up stain pens to repaint the grain lines that might have been lost in the bleaching process. You will need to buy at least 3-4 colored wood stain pens to match all the different colors lost in the wood. Try Lee Valley Tools. Here is the URL of their product. http://www.leevalley.com/wood/page.asp?SID=3D&ccurrency=3D1&page=3D20067&category=3D1,190,42997 Once you have the stains re-colored and dry at least overnight, then you can touch up the oil/varnish floor finish. You can stay with the same brand of Dura Seal at least for the touch ups, and apply as many coats just at the same rate and dry times as your flooring contractor used. Even this stuff cross links (hardens) a bit, so it’s always wise to steel wool between all coats to get good adhesion. If you are interested in a better, less toxic oil/varnish that has a much better film build than the Dura Seal you could try a product called Tried and True oil/varnish. While this is mostly used on furniture (because this lighter duty use is more in keeping with oil/varnishes in general) it should be better than Dura Seal because it is all oil with no toxic solvent thinners. But it will take at least 5-6 total coats of oil/varnish to give you some water resistance. You already got 2-3 coats on the floor now I only resume. So only one or two more coats may be needed to make a better more water proof surface. You might just try a small can (it’s expensive) of this stuff and do a sample spot on a high use area. See how it works for you. Here’s the URL of the Tried and True products.

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The smell that goes along with urine and feces stains could be eliminated first or later, and for that I will refer you to the good folks at the Cleaning center at www.cleanreport.com. Don Aslett has written a good book about this very odoriferous subject, called Pet Cleanup Made Easy. You may find you have to use their odor treatments (their X-O treatment works miracles) before and after the bleaching. The odor may be coming from under the floor, on the baseboard and even on or in the wall in some cases. The alternative to bleaching out stains is to repair them out. Click on the wood floor repair article (it’s free). https://www.woodfloordoctor.com/_how_tos/articles/repairconanddiy.shtml This is a must read before you begin bleaching the wood. You may find that if you have the basic carpentry skills, a wood floor repair of the stained areas suits you better. This is what most professional do, as we charge by the hour for repairs. We cannot always experiment with wood bleaches on our client’s floors. We must have a certain and predictable time to completion. And in our case removal and repairs are often the quickest way to go, but not always the cheapest.  

Question: I have hardwood floors that have urine stains from previous owners. I discovered this when I pulled up the carpet. I would love to have them redone but I have been told that the stains would still show. Is there anything that could help? No one mentioned bleaching, and there are too many stains to replace sections. I took some sand paper and sanded a small section and the circle of stain still shows. What do you think? It may be hopeless. Please give your advice. Thank you, Kathy. Answer: Dear Kathy You can certainly try bleaching with the strongest wood bleach available. It’s called Klean Strip at www.kleanstrip.com. It will turn the dark areas an off white color. You will need to do this after the floors have been sanded, but before any finish has been applied. The wood is very susceptible at that point. Don’t spill anything on the good wood. The off white colored spots will need a light colored wood stain to blend them in to the rest of the floor. It’s quite an art. You will want the color to blend in with the final finished color of the floor, not the bare wood. Or you can darkly stain the whole floor, after bleaching. The spots may show up a bit, but no so much as now. And lastly, major repairs, or replacements. Or a combination of all of these methods. Find an old (or young) floor master in your area, that does these things, and will give you advise in person. And please read my article, which can be found at the top of this web page in the search box on hiring a contractor. If you cannot find someone with good touch up skills, have the floor sanded only and do the bleaching-staining and finishing yourself. That’s the fun part anyway.

Question: I am in the process of milling a black walnut floor for a big ticket room remodel. In the past I have used Minwax fast dry oil poly with decent results. My own floors are finished this way and have no wear in over a year. This walnut, however is going to go in a family room and will likely see more traffic than my bedrooms and hallway. Finally, the QUESTION. I am interested in finding a quality professional finish to protect “my” walnut floor, and my reputation with the client. So, what is there ? Bear in mind I have done a good bit of floor finishing with poly over ther years, and have a lot of experience in spraying lacquers and conversion varishes. I would like to know about miosture cured poly, and it’s application. Dan Answer: Dear Dan Let’s review your choices for this lovely wood. Most of the catalyzed water based finishes like Street Shoe and Traffic are out. This dark wood will take on a sickly pale tone with these really durable but rather opaque finishes. Then there are the solvent based conversion varnishes. first the Swedish acid cured finishes, which emit formaldehyde gas for 90 days after application. These are clear and very durable finishes, but unless you inform your client of the health risks involved, this stuff is out also. That all said, then there is the very durable Moisture Cured Poly. Besides the fact that this finish has up to 7% toluene ( the stuff that been killing glue sniffers for years) this finish is also not suitable in your case. It’s because of it’s adhesive nature. It can literally glue new boards together and they will crack themselves as they move seasonally. This is called panelizing, when ten boards will pull and eleventh one in half. It happened to one of my floors, so I’ll never use this stuff again. Oh, that’s why when doing Street Shoe or Traffic on other floor, you should always use two coats of a weaker acrylic sealer. So that leaves lacquer finish,which after reading my article in the Floored News about Lacquer Finish Floor Fires, I don’t think so. And then there is the really weak kneed oil/varnishes, which are not meant for floor use. So, guess what, That finally leaves the Oil Modified Poly. But the Minwax brand you have been using, I’m not too fond of. Try the Fabulon brand professional oil modified heavy duty floor finish super satin/clear, it’s simply the best. I have written a long article on how best to apply this finish, without the bubbles or pits associated with this stuff. The satin poly will make this walnut floor look stunning if you apply it correctly. It’s not rocket science, but I have my secrets to a silky smooth satin finish. As always your Most humble servant, Joseph, the Wood Floor Doctor.

Question: Black stains of unknown origin appear on our hardwood floor. In the last mysterious case, they appeared after an oriental rug that was in this particular place for several months was shifted by ~ 2 feet. Next day, the area previously covered by the rug had several large (on average, 4″ size) black stains of various intensity and irregular shapes. Some are black while others are transparent but darker than the usual color of the floor. Solvents do not remove them. We would like to understand where these stains come from before attempting to cure them. Thank you for your attention to this matter. Answer: Dear Vadium, I’ve had something similar happen to one of my client’s floors. We discovered that the underpad beneath the area rug had black coloured foam bits in it and the colour was migrating into the floor finish. Solvent woudn’t take it out so I had to sand off most of the surface finish and recoat that area. In the rare case the dye from the carpet will migrate into the floor finish but I’ve yet to see this and in this case there would no underpad. Change to a better quality underpad, or use one if there is none. There is one more possibility and I’ve only seen this once in 22 years. There is a blackish blue fungus stain that is associated with oak. This will appear only when the temperature and humidty is just right for this organism to grow and leave it’s coloured stain behind. In this case we had to resand the whole floor and to my knoledge it never came back. But they first appeared as dots no more than 1/4″ in size. I hope I have helped let me know what you discover. This is a very curious problem and I just love a mystery, just sorry it had to happen to you. 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: Hi, I bought a brand new house in Aug, 2001. Birch hardwood floor was installed. It’s site-finished. After a month, the floor starts to crack. Some of the wood strips started to contract. Now it’s Feb 2002, gaps become much bigger. They ranges from 1 mm to 4 mm. Is this something within the normal range? The builder is going to fix it by putting in filler. But I think 4 mm is too wide for filler. Am I right? Should I ask the builder to replace the pieces that significantly contracted? Regards, Frank Answer: Dear Frank, Here we go again the amazing winter shrinking floors. This is especially a problem with prefinished floors, and if the floor was stapled down on OSB as the subfloor, there will be all kinds of shifting. But wait. Have you been doing your part in stabilizing the environment this solid wood is in ? You should maintain an indoor humidity level of about 40-60%. And I mean all year round. So, if this was a particularly hot and humid summer (a long one at that) in Ottawa, you may have been tempted to throw the doors and windows open, rather than waste energy using the air conditioner. Prefinished floor are not finished on site, so they are susceptible to these high humid conditions, and will swell up quite a bit. The boards will push against each other, and move into the expansion gaps at the long edges. You will not notice this. The indoor humidity can easily reach 80% for weeks if not months. But at some point in the Fall we turn the heat on and bake these floors to desert dryness. An un-humidified house can easily reach a 25% level in the middle of winter. These extremes on solid wood will cause the wood to reach an equilibrium moisture content of as high as 14% in the summer and as little as 5% in the dead of winter. And this movement will easily cause the gaps you speak of and worse. The immediate goal is for you to bring your indoor humidity up to at least 35-40% right now. If you are uncertain of your indoor humidity get a wet-dry bulb thermometer at http://www.e- sci.com/genSci/9/1044/1099/9955.html. This is the proper instrument to measure indoor humidity. The cheap metal ones are not at all accurate, and may mislead you. You can use a furnace powered humidifier, or the portable ones. And in the summer be sure to de-humidify your basement, constantly. and when the indoor humidity level reach past 60 % use the air conditioner. Do all this if you expect your solid wood floors to stay tight. The gaps that you have now are probably permanent. Don’t put any filler into prefinished floors, it never looks good. In any case wait until spring before you do any filling, and do it sparingly. Don’t even think about repairs until the spring, the floors amy have corrected themselves by then, if you have been diligent in raising your indoor humidity. This sort of thing almost never happens to my site finished floors, the wood is so well sealed that the humidity changes affects it very little. A thick plywood subfloor helps also, and floor nails must be used, never staples. I bet you were never informed of any of this when you bought this floor. As always your Most humble servant, Joseph, the Wood Floor Doctor.

Question: Amy My husband and I want to install hardwood floor in our living room, foyer and dining room; however, we have a dog that’s 75 lbs. Are we asking for trouble? What is the most durable finish? Should we consider other flooring? Answer: Dear Amy, I think hardwood would be OK in the living and dining room, but consider ceramic or better yet real linoleum in the foyer. Don’t even think about those prefinished wood floors in your situation. This is because even though the finish on these floor is just about indestructible the wood is not. The dogs nails will dent the wood and gouge the wood, and in no time your perfect factory finish will look pretty banged up. These floors are just about impossible to touch up. All that said, choose a white oak (it’s harder than red oak) or hickory and maybe install it yourself but have it professionally sanded. These woods are ring porous so have a texture which disguises the scratches well. Avoid the fine grained woods like maple. Finish it yourself with a finish that you will feel comfortable recoating it yourself. I still like the oil based poly. But you can try the water based finishes. Some are more durable than the oil poly but are poisonous to use ( the catalyzed water based finish has a poisonous additive). Check out the article on the Dura Seal 1000 water based finish in the Floored news section of this site. This finish is about as durable as the oil based poly, and it dries a whole lot faster. But it is new on the market, so we don’t know how well it will age. The main thing is to use a finish that you will feel OK about touching up and recoating yourself, not hiring an expensive pro to do each time. This would be the case with the industrial catalyzed water based finishes. Very hard but only sold to pros because of the health risk. But by all means have the pro sand the floor, this is not a job you should be doing yourself. I’ll explain why if you wish. Oh, and use lots of area carpets, and be sure to read my floor cleaning article in the Floored News. As always your Most humble servant, Joseph, the Wood Floor Doctor.

Question: Hi. I just bought and read your article on how to sand a floor without leaving machine marks. I am in the final stages of having a new, solid 3/4 inch white oak floor installed throughout the main floor of my house. I am not attempting to do any of it myself, and have hired someone who came very highly recommended and who does many high-end homes in this area (San Diego, CA). My house is just an ordinary one but of course I want a nice floor. This guy has been doing floors for 25 years, and his father and grandfather before him; but it surprised me that he used circular sanders for every stage of the process, finishing with a 120-grit screen, and I can clearly see millions of circular scratch marks over the entire surface of the floor when the light is at an angle. I mentioned this to him and he was very surprised, and said everyone does floors with this type of sander and no one had complained about it before. I notice in your article you assume a drum sander will be used; but for the final stages you do mention “screening”. In your method is this screening also done with a drum sander or with a circular sander? In your opinion when is it OK to use circular equipment, and even in the final stages how would you avoid the circular scratches? My floor now has the second coat of oil-based polyurethane applied (there was no stain used) and the scratches are everywhere. How is that possible with 120-grit? Thanks Debbie Answer: Dear Debbie, I know of NO professional floor sander in my area (Greater Toronto-about 6 million people) that uses a buffer (also called floor maintenance machines) to intially sand the floor. We will ALWAYS use a drum (or a belt) sander to level the floor and take it down to the final polishing of the wood. This is because, as you can see in the article’s pics the sandpaper travels WITH the grain of the wood. A well tuned drum sander leaves no marks in the wood. And as the article goes on to suggest, we only use the buffer with screen (100 grit) to do a final light polishing of the wood surface. In fact this is mostly done to blend in the edger marks with the middle of the floor. Or to remove any egder marks in a cross laid hallway. In the extreme case when there are severe chatter marks in the floor would we consider using a large sandpaper disk (100 grit also) to remove these errant marks. Then we return to the screen to remove even the sanding disks marks. A screen is simply an arbrasive nylon mesh disk that fits under the buffer. I’m including pics of the buffer in use and the screen. The buffer and screen are also used to smooth out the finish between coats. And even then we use fine screen, somewhat worn, so no circular marks show in EVEN in the finish. Here is the URL of a fairly new machine that some pros are going to be tempted to use to sand floors. The have their place when doing the final wood polishing of parquet floors. But others will want to use these machines for sanding (and creating circular marks) in strip floors. Go figure. http://www.laegler.com/html_e/p_trio_te.htm The finished wood floor should look as good (better really no “over-wood”) as a prefinished floor. No machine marks should be visible at all if the floor mechanic is doing his job correctly with the proper equipment. I hate to say this, but I’ve seen guys doing floors the wrong way ALL thier lives, with no improvement. I’ll bet you didn’t go over to see some of his “custom jobs” like I suggested in my article How to Choose a Flooring Contractor” free in the How To section of this site. If he has sanded the floor with aggressive screen or sandpaper disks, no fine sanding with these same disks will remove the marks. The marks are just too random and embedded into the wood surface. I hate to say this, but you’ll have to have the floor done all over again, by someone that does know what they are doing, and has the proper equipment. Before you ask, no, there is no one I can recommend in your area, I only talk about products and methods. People change (or not). Find the guys who will use the best methods, and the job will go swimmingly this time. Oh, and good for you for reading what is a really technical article, just to find out how the work is really supposed to be done. I hope this has helped.

​Question: Hi, I am interested in becoming a part-time floor sander. I checked web sites but cannot find a dealer carrying floor edge sander and drum sander in New Jersey. Can you tell me where I can find a good company selling this equipment? Thanks. Harry Answer: Dear Harry By all means DO try a career in this business, it’s quite rewarding if you love wood like I do. And I sure do recommend a sander or two. The Clark is a great machine and has a long history in North America. They took over the American Lincoln floor machines company, and have made their machines based on this old venerable model. It’s similar to the machine I use, and mine is about 30-40 years old and still going strong. Alto now owns the Clarke machines at http://www.regalequip.com/Alto/clarke.htm. I would highly recommend their American 8 floor sander. But there is an alternative, and that is the Galaxy Floor machines, which are copies of the old Clark, (the Galaxy 506) and are made one at a time by a real machinist right here in Toronto. They finally have a web site at http://www.galaxyfloormachines.com. Both these machines may have to shipped to you directly, but I trust both machines, the Galaxy 506 and the American 8. If you are at all serious about staying in the hardwood floor business, you must have a powerful and heavy machine, and only 220 Volt machines will do. They weigh over 200 pounds so that they don’t chatter across the floor when you fine sand. It’s no so much a matter of speed, (they ARE twice as fast) as the fact that you won’t get paid for jobs that have chatter marks all across the floor. You can always dismantle these machines into two 100 pound loads. I hope you are a big guy. All houses have 220 volts coming to the main fuse panel these days. I live in a 100 year old house and this has been upgraded in the 60’s, as most houses have. If you go into your main fuse panel you will see two big wires coming in from the street. Test them with a 110-220 voltage meter and I’m sure you will see what I mean. All electric stoves and electric dryers run on 220 volts, so in most house you can hook up your cord with an adapter to plug right into these receptacles. You are gong to have to have a few lessons from an electrician, about how to do this until you get the hand of the many variations of this. You need about 30 amps at 220 V to run these machines. It took me about a year of full time work, before I had the knowledge to do work on my own. You should really consider working for a well-established firm, before you start experimenting on customers? floors and electrical systems. But I will be here whenever you wish to ask anything about wood floor. Be sure to read some or all of the books I recommend available in the search box at the top of this web page.

Question: For future reference, since I will be selling this house and am sure to install hardwood floors again, what is the clue to a final sanding without even fine scratch marks?Thanks, Debbie Answer: Dear Debbie The clue here, is to use the same oil based poly for all three coats over the stain (if any). This way the screening marks will self heal, and because it Using Threreis the same finish for all coats no marks will show. I know because my work has been scrutinised for years, and shows no such marks. His work will always show some screen marks because he is wrongly using an old fashioned penetrating sealer as the first coat. It has almost no film build to it, and when he screens it, some scratch marks go though the sealer. And then when the poly is applied it colors the wood slightly differently (because poly is a much different product these days than the penetrating sealer), and hence shows the marks. Also he needs to learn better screening techniques, this is quite and art, that a lot of floor guys don’t get. I’ll probably write two companion short articles in that Sanding w/o machine marks dealing with the buffer and the dreaded edger. But that’s for next year. Save the URL as you will have access to any updates at no cost, and save your Paypal receipt in case we change the URL. Only on the web could we do this. You just cannot these days mix old (penetrating sealers) and modern oil modified poly’s. You can see the results. If you are curious as to all the details that I use to apply 3 coats of oil poly to my floors buy and read the “Poly w/o Bubbles” article, on the Home page. Offer to split the cost with the contractor, so he can read how it’s done, so no complaints will ever come about. I try to take the best from old methods and use modern products, to create great looking but durable floors. As always your Most humble servant, Joseph, the Wood Floor Doctor.