Question: We are building a new house and have chosen pre-finished hardwood for our bedrooms. The problem is that the plywood on the second floor does not seem to be leveled perfectly. Pre-finished planks will obviously not be smooth. Is there a way to level the floor before installing the hardwood planks? Are these leveling compounds safe for our health? Answer: Dear Muneeb It may be that prefinished is not the route to go. You can sand about 1/8″ off the high seams of the plywood, providing that it is at least 3/4″ thick. If you have a thinner 5/8″ plywood subfloor don’t do this. Don’t bother will all the claims of those leveling compounds, they will crack when nailed. And these are all really meant for concrete subfloors in any case. And the gypsum based ones are the worst of all. So don’t be afraid to sand off a bit of the subfloor, and install some shims. I like to use glued and stapled down 1/4″ plywood and sand off the edges to fill in dips of that depth. Then staple the plywood edges after. You do all this sanding of the subfloor with a floor edge sander loaded with 16 grit sandpaper. Then I would strongly suggest installing an unfinished hardwood, and have it sanded professionally on site. The first passes of the floor drum sander should be done at a diagonal to the run of the boards. This will level the floor perfectly. Consider doing the finish yourself that’s the fun part anyway. And in your case it may be the only way to get a really smooth floor.

Question: Greetings! I have a subfloor in a third floor complex that is in various degrees of being unlevel. I don’t think the cement type floor leveler is suitable for this, since the old sub floor is fifty-year-old planking with wide gaps. What is the trick to building a shimmed floor on top? How do I assure that it’s level in all directions? Ron Answer: Dear Ron You are correct in assuming that a poured cement leveler is the worst choice in this case, they simply crack apart as you nail through them. And over time they will degrade. Shims are only meant for small 1/4″ localized dips in the floor, not much bigger than a foot across. But you can shim along a whole wall this way. I use 1/4″ plywood glued and stapled to the plywood. Then I use my floor edger and sand down the edges flush with the old subfloor with 16 grit sandpaper. Let the glue dry overnight and then lay the floor. Cedar shims are no good, as they crack when nailed. Now that said, when you have a major humpy floor, you should bite the bullet and remove the subfloor planks down to the joists. Then sister the joists will LVL joists at exactly the level you want. Lay a new 3/4″ plywood subfloor, and Bob’s your uncle. You will have a level sound surface to lay your new floor on. In some cases we will sink the subfloor between the joists on plywood ledges and on the other end of the room the sistered joist can raise it up to the desired level. This splits the raising over the entire area and minimizes any extreme ramp up. Yes, expensive, but a permanent and proven method. I cannot give you the whole method in detail by email, but if your carpentry skills are not honed, you really should hire a pro for this anyway.

Question: I just discovered hardwoodfloors in the home i purchased. They’re in good shape except for the previous owners Stapled padding to the floor. What is the safest way for me to remove the staples without causing damage to the floor? Kim Answer: Dear Kim I use a Lee Valley’s restorer’s cat’s paw at www.leevalley.com (prod. # 60K21.06). It will get under most of the staples and with it’s large surface prying against the wood, with care it shouldn’t harm the wood. And for really stubborn staples, ones that have broken in half, I use the nail puller, Prod. # 64K02.01. And if that just snaps some off, simply use a fine nail set to set the errant staple wire below the surface (prod. # 23K17.01). You can then fill all the little holes with a colored latex putty (#80K86.01), but be sure to wipe it off BEFORE it dries with a wet rag. As always your Most humble servant, Joseph, the Wood Floor Doctor.

Question: Hi, We recently bought an older house (50+ years) with wood floors throughout. There are many areas in the flooring that have 1/8″ (or more) gaps between boards. I’ve considered using colored wood putty to fill them, but I’m not sure this is the right way to go. What do you suggest? Thanks for your help. Kent. Answer: Dear Kent You can fill the gaps before AND during the sanding of the floor. I only presume that you plan on sanding the floor to the bare wood. While it’s always best to fill gaps before you coarse sand a floor, you don’t always get them all. Before you do the medium grade sandpaper, fill all the spots you missed, with small amounts of filler. Just don’t goop it on this time as the medium paper will get clogged and become ineffective if it encounters too much filler. Don’t fill anymore after medium sanding, as the fine sandpaper clogs to easily. My favorite filler for small gaps and holes is the Le Pages brand at http://www.LePageproducts.com/ProductCatalog/detail.asp?catid=25&subid=56& plid=305&PID=687. That said, this is a colored latex filler of good quality, and can be uses for gaps up to 3/16″ and holes up to 1/4″. Choose a color that is a tad darker that your finished floor. As the floor darkens with age it will look better. You can mix the colors. Filler is no substitute for wood, so in loose gaps it won’t stay in long. And it you have gaps 1/4″ and wider you will need another method, tell me if this is so. Loose and squeaky boards can be re-nailed, tell me if you need to know this also. Now once you have applied all but the last coat of finish on, you can still do a bit a spot filling with these tubes of filler. But you have to be sure to wipe all the excess off right away, or else it will dry as a smear on the finish. Wait 4 hours for it to dry before you coat for the last time. In the unlikely event you don’t plan on sanding and finishing the floor, you could try this also, but it will be very time consuming, and the filler won’t have a coat of finish on top to help keep it place. Best to wait until you ARE ready for sanding and refinishing before you attempt to fill it. Unfortunately most of the commercial floor fillers sold in large buckets don’t stick to the wood very well, and crack out during the sanding. You can make up your own recipe if you have access to red oak fine edger dust, and I can tell you how.

Question: How difficult is it to build a new floor 12’x20′ about 14″ above an existing floor? We would like to eliminate a sunken living room effect. There is plenty of overhead space in the cathedral ceiling. Answer: Dear Roger It’s not too difficult if you have some carpentry experience. First lay a kiln dried pressure treated 2 by 4 (laid on side) padded 16″ o.c. framework to the concrete. Try www.maplefloor.com. For good illustrations of padding for sports floors, you can use the same pads for under the 2 by 4’s. Then I suggest you use LVL’s (laminated veneer lumber) of about 10- 12″ thick in a bracketed framework, to the 2 by 4’s. Then add a 3/4″ plywood subfloor to this and there you are. You could choose to powder nail the 2 by 4’s to the concrete, but consult the methods and suitability of your concrete before at http://www.patmi.org. You could also glue (urethane construction adhesive only) shorter pieces of 2 by 4’s (no more than 4 feet to the concrete. But the padded method will give you the least hollow sounding floor.

Question: Doc, What we wanted was a wide plank floor 6-8 inches. We can’t find a tongue and groove that wide which leaves us with face nailing. The questions in my mind are: -will this “bow up” if I don’t use T&G? -will there be significan split in the seams? -will this be more likely to squeek or come loose? -should I just abandon this thought and go with a 4 in T&G and sacrifice the rustic look I was trying to go for? Sorry if this is too much but I am getting frustrated with trying to figure this out. I get many different answers from many different folks. Thanks, Chris Answer: Dear Chris Now I finally understand what you want to do. Even though the article clearly lays out the best way to install a plank floor, in good detail, our forefathers had no such milling of lumber when they installed plank floor in the early colonies. Wide planks were the regular thing, as the wider they were the less side milling required. Random widths were used simply because they were cut right from the tree though the boule. Narrow lumber from the outside edge of the tree, and wide through the middle. So let’s get to your case of installing a square edged pine floor or hardwood for that manor. If it’s the rusting look you want this is what you’ll get. First make sure that you have at least a 1&1/4″ thick plywood subfloor. If not add enough thickness of smooth underlay plywood to get it that thick. This is so the flooring nails will have something to grip. Oh, and repair and renail any existing subfloor before you apply the underlay plywood, so all surfaces are squeak free. Install the underlay with lots of ringed shanked nails (6″ on the square), just long enough to go into the subfloor but not through it. You can use longer nails on the joist joints. You are going to try and create a fairly unbroken vapor barrier so no nail should go all the way though. The wood you want to get will have to be well edge milled, and fairly straight, and long pieces. And most importantly it has to be KILN DRIED to the EMC (equilibrium moisture content) of indoor wood in your region. Find this out from a cabinetry shop or a wood flooring company, and make sure your wood starts out this way. If you try to air dry outside stored wood, it will warp and twist, and not be suited at all. Install the wood leaving a 3/4″ gap at the edge wall for expansion. And I would like to so these planks glued (with a urethane adhesive, I mention a few brands in the article) and face nailed with the Tremont nails. The rose headed nails wll hold the best, but you cannot use them as you will be sanding this job on site. So just use their finishing nails with the fairly small head : http://store.tremontnail.com/cgi-bin/tremontnail/items?mv_arg=6 In your case since these are the only nails you’ll be using, I want you to nail all the ends of course even where they meet the wall. Cover this last row with a wide moulding or baseboard. Two nails in each end. And then as many nails as you can stand to see, intersecting with the joists. Oh, and of course this floor MUST be laid at right angles to the joists. 2″ nails are used on the ends, and 3″ will go through both floor and subfloor into the joist. Predrill all the nails to prevent splitting and stay at least an inch or so from the edge also. You will have to pry and coax each and every board in place so they are as tight as possible. Use a prybar against a temporary nailed board in front of a stubborn piece. It’s a real bear of a job. Use the adhesive sparingly, only on the ends (never glue up two boards together) and some more dabs every foot or so along the underside of the board, especially where the joist nails will go. Urethane adhesive is very very strong, and if you try to glue the entire floor, and it fails. Well you will just never be able to remove it. That is also the reason for the underlay plywood, you can always remove the plywood with the failed floor if you have to. It’s a slow installation one board at a time, glued and face nailed. Then set and fill all the face nails with a colored latex putty. Let the putty dry overnight. Sand the floor silky smooth (or better yet hire a pro to do just this task) and finish the wood with at least 4 coats of oil based polyurethane, for really good moisture resistance. (read my poly w/o bubbles article). And it also would have been a good idea to apply just one coat of poly to the underside of the boards about a week before you installed then. This will minimize the warping as both sides of of the wood will be finished and have about the same EMC. And to answer you last question, yes this floor will probably warp and squeak and gap, IF you don’t really pay attention to the indoor humidity swings, as I mentioned in the article you have already bought and read. So if all this sounds like too much work, just buy the standard 3&1/4″ wide T&G strip floor and blind nail it simply and easily with the flooring nailer. A 4″ wide plank is still begging to be face pegged, as I mentioned also in the article. It just depends on how narrow you indoor humidly RANGE is. And don’t you worry, it’s never too much to ask the Doc, this is exactly what I am here for, to give you the most realistic look into all the wood flooring options, and ALL my 25 years of experience. You are actually helping me improve the articles with you additional questions. As always your Most humble servant, Joseph, the Wood Floor Doctor.

Question: Doc, So, question #1 – Can I put down 1/2″ solid Mesquite on top of my slab (assuming I follow all the other recommendations in your article concerning moisture and flatness testing)? If so, what’s the maximum width you would recommend? Problem #2 – the wallboards extend straight to the slab. Have you ever encountered this before? Aren’t you supposed to slide the floor under the wallboard for purposes of expansion? How can I do this if the board runs all the way to the slab? Should I remove all the wallboard and take 1/2″ off with a band saw? Is there a horizontal circular saw that can cut this without me removing the wallboard? Finally, we are removing the old carpet and wondering what to do with the old carpet tack strip nails. Every time I pry the nail that holds the strip down out of the concrete, it takes some concrete with it, sometimes as much as 1.5″ in diameter. Is there a better way to remove these nails? Should I use my dremel and just cut them off, or is it really even something to worry about? Thanks for all of your help. Steve Answer: Dear Steve By now you’ve read my “wood floor on concrete” article and you see all the choices, good to not so good. And the solid wood strip laid directly is the not-so-good. Before I start into your answers (to lots of questions, whew !), I’d like to direct you to Kentucky Wood Floors. They still make traditional patterned solid wood (3/4″) thick parquet. Take a look at the photos of these elegant floors, these are the real Mc Coy. Also they do produce a laminated (engineered) wood strip floor, that has a top wear layer of 1/4″. Installers are raving about the way this material fits, and stays in place as you lay it. It’s the best of this sort of flooring made by a company in this business for over 25 years now. Here’s the link : http://www.kentuckywood.com/ Now as to your question. While it is true that mesquite has very small movement in service, it is just about similar to teak, cocobolo, and even quarter sawn red oak. But be warned that there is some movement, because this is solid wood after all. You cannot glue down a great expanse of any kind of solid wood strip floor (more that 20 feet in width) and have it perform well, unless you keep indoor relative humidity levels within a 20% RANGE. And the ideal range for hardwood floors is 40-60%. Next time you visit a museum check out the accurate electronic hygrometers on the walls. They keep the collections pegged at 50% RH all year long. Mesquite has a projected seasonal range of movement of .0013. So given a safety factor of +25% even mesquite will expand and contract .4″ over just 20 feet of width. This when the EMC (equilibrium moisture content) of the WOOD changes from 6% in the winter heating season, up to 12% in the middle of a muggy summer (this would be caused by a more realistic indoor humidity range of 30%). A site finished floor will reach these extremes but much slower than a prefinished floor. Any gaps that form will be small and more evenly distributed with a floor well sanded and finished. This projected movement is based on a more realistic indoor humidity range of 30%. The only problem with a site finished mesquite, is that it will be a bear to sand. Choose a well seasoned professional floor sander in your area, so the coarse sanding marks don’t show through if you go this route. So yes, this stuff is comparatively stable, as long as you stick to the sizes I recommended in the article. I’ll repeat this here : “These have to be specially milled for this purpose. They will need to be no more than 2 feet long, and have a flat underside. And they should not be more than 1/2″ thick and 2″ wide. If you look at the standard strip floor you will notice it has a grooved bottom which will not contact the glue as well as the flat milled bottom”. Just remember the vender is trying to sell you something, I am not. Also the key here is “flat milled bottoms”. It’s not an easy installation unless the wood is perfectly milled. Have the salesman provide some references of professional installers that have used this particular mesquite product, they will tell you how well the product is made. If the store refuses this, go somewhere else. To the second question, just remove the wall board (up north we call it baseboard, or molding) carefully and install the floor with the appropriate expansion gaps, and replace the baseboard on top of the floor after the job is done. It will neatly cover the small gaps. If this is really thin baseboard, you can remove it and even undercut the drywall (don’t break the vapor barrier) by scoring the drywall with a knife and removing that small strip. Then replace the baseboard. This will give a wider expansion gap as drywall is 1/2″ thick at least. Removing the baseboard is tricky without snapping this thin modern stuff, so use a backer board to protect the wall as you pry it off with a tool like this : http://www.leevalley.com/wood/page.asp?SID=x=1x=32014x=1,43456,43399 But if you don’t want to remove them you can buy or maybe rent the Crain jamb saw at http://www.craintools.com/fs-specialtysaws.html The last question, just pop the carpet strips off, the damage occurred when the nail was hammered in anyway. Fill with a non shrinking mortar, it’s easy.

Question: We bought a new house that has hardwood flooring in the foyer and kitchen. We are in the house 4 months and noticed wide gaps between the planks. Some I can even put a dime, nickel and quarter down the gaps. Is this normal? Is this an installation problem or refinishing problem? Denise Answer: Dear Denise 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. In your case there may be a corresponding seam in the subfloor and some minor settling of the foundation can also cause this shift. It’s not so alarming just something to keep track of. 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 in your area, 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. If you have to do repairs you will have to find a board a bit wider that yours, and of the same species. It will have to be ripped to fit. In the mean time read my article about wood floor repairs in the Hardwood Authority section. 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. And I always re-nail my subfloors with 3″ nails before I start. As always your Most humble servant, Joseph, the Wood Floor Doctor.

Question: Hi, I bought a brand new house in August. 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, gaps become much bigger. They range 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.

Question: Do you know anything about Kempas Engineered hardwood floor? If you know please let me know if it is good. Thank You. Answer: Dear Farzad I don’t make comments on a prefinished floor that I have never used, but if you read the Prefinished article which can be found in the search box at the top of the web page, you will see what I think about the engineered wood floors. Suffice to say for now that the 2 and 3 ply engineered wood floors will act a lot like real wood, defeating the purpose of their plywood nature. A 5 ply material (5/16″) would be better, but alas they are getting harder to find. But generally speaking the Kempas wood itself should make a pretty hard and durable floor. It’s at least as hard as maple and as long as all the plys are all hardwood in the middle you should have no problem with this wood. There is a tendency for this wood to split along the vein lines of abnormal wood. But in the finished material they should already have cut this wood out. If you are curious to find out why I believe these thicker 2-3 plywood engineered floor may be trouble in the long run.