Gaps the size of a nickel after installation

Q: We installed a 5″ select white, glued and nailed, unfinished oak. The subfloor 11%. The material 10.2% finished with stain and LNL 1500. On installation the floor was tight and now there are visible gaps the size of a nickel. Can this floor be sanded, re-hydrated, and finished? If so, what process would you suggest?

A: The moisture readings, while not outrageously high could have been a percentage or two lower, but the difference between sub floor and oak is okay. If the air is dry you could run a humidifier. It isn’t often I see a floor that is without some small gaps. And the wider the board the greater potential for increased shrinkage.

This is probably not much help, I know. But controlling the environment is one of the few things we can have some control over.

Follow-up Q: Do you think resanding the oak and adding moisture to it by spraying water – similar to popping – will close the gaps? The house does have a humidifier in the heating system. We are desperately trying not to rip this finished product up.

A: Spraying water on the surface doesn’t have a hope of expanding the planks. I don’t think anyone can ever guarantee a wooden floor will stay tight and never get any gaps. NWFA has always held to the view that a gap about as thick as a dime is normal and expected. I would suggest to the home owner they give the floors time to go through a couple of complete seasonal cycles. It’s probably going to expand a bit in the humid summer. If you have a hygrometer set it on the floor for 15 minutes to see what the moisture level in the room is. I know you can’t have humidity up over 45 RH on cold winter days. But if it is down to 30 or less, that will suck the moisture out of everything. Did you give the flooring time in the rooms to get used to the environment?

Follow-up Q: Yes the flooring was in the house for a week. The only issue with waiting is this is a new construction so the house is presently empty. I will be doing RH testing and moisture reading tomorrow.

A: I figured it was new construction. I really don’t like doing those jobs. Other contractors are crawling over each other and everything gets rushed at the end, whether it’s ready or not. Back in the early days of self employment when I had to do sub contract work, there were a lot of jobs in new sub divisions. Installation of Bruce. There was no acclimating the flooring. The last week before closing, every trade was in the place. Every rule and precaution were broken as far as flooring goes. I kept telling the builder, if this floor goes south, it isn’t my fault.

One of the worst I saw was when I lived in Niagara. I got a call to look at a floor in a sub division. It was all badly cupped. Clearly the structure was not dried out before the floor went in, and the wood swelled. The builder told the home owner the floor meets warranty specs. I couldn’t believe it.

Black dots where area rug pad was

Q: We have a house with 60+ year old oak floors. There were 30+ year old area rugs, that had a reddish/brown pad under them. The pads left black dots across the floor. Can these be cleaned/removed or do the floors need to be sanded?

A: You may have a bit of an issue with this. These black dots are probably water stains from the carpet being steam cleaned or shampooed over the years. The moisture telegraphed to the center of the bumps on the underpad, it sounds to me. So, yes the floors will have to be sanded. Hopefully the stains can be removed. If not you would then have to stain the floors to hide the marks. This all hinges, of course, on whether these old floors are thick enough to handle a full sanding. It depends how many times they have been done in the past and how thick they were originally.

Follow-up Q: Thanks for that info Craig. I should have said that the rugs were never cleaned or wet. A rug guy thought that perhaps the rug mat/pad might have had some clay in it? The dots are uniform across the entire rug area, 1 inch apart horizontally and vertically. Some areas the dots are darker, but again it is uniform.

A: Even a tiny bit of moisture over time could do it. Perhaps dampness from beneath, transferring slowly through the floor over the years. The pad was just another layer to slow that moisture down and trap it against the wood. I did a floor years ago which had that pattern on the wood. It wasn’t even dark spots. It was just the outline of the pattern, as if it had been x-rayed into the wood. It was the strangest thing. It didn’t even sand out.

Splits and boards cracking up the middle

Q: I just had 890 sq. feet of A——— Hardwood floor installed in my house. They delivered it and started install the same day. The workers installed all 890 SQ. in two days.

The same night I notice my socks getting caught on some planks. I then saw many boards that began to crack up the middle and along the sides where joined. There are about 65 splits in a hallway that was 100 inches long by 60 inches wide. I design kitchens and the company that installed does our floors.

He said it was cupping due to a manufacturers defect. He basically told me acclimation was a farce. He agreed to replace all and brought wood to sit for 5 days before new install, just to appease me. Well I found out he was using A——— builders hardwood again. Is it due to poor quality?

It’s not done yet, but the hallway has just one board that’s split. He will replace it. The living room has just one split I can see because the cardboard is covering it while they do other rooms. He said splits are expected because it’s natural wood.

Is this acceptable and do I have to live with wood that splits up the grain of the planks? It’s not even finished yet and I afraid to complain. Am I being a nut case or should I stand up for myself? Please Please Please help me.

A: Absolutely stand up for yourself. The splits will get worse when the finish is applied. If this product is a cheaper grade or even mill run, then yes, you will get that type of thing, but they should be picked out and not installed.

I disagree that acclimating is a farce, but the main issue here seems to be poor product. I wouldn’t have that in my floor and you are right to complain. If I was installing this floor, I would be complaining to the people where I bought it.

Similar Q: We had solid white oak flooring installed, B********, and we have had vertical cracking occurring. Do you think this is a defect in manufacturing? What causes this? Any remedy?

A: I’ve seen this in a couple of white oak floors, about 65% rift and 35% quarter sawn, several such boards had crept into the installation. I would think the best thing to do is replace the affected boards.

Brown stains from straight vinegar on bare wood floor

Q: I accidentally mopped a newly stripped hardwood floor with straight vinegar! Now I have
brown stains circling my floor. Tried bleach, I know it’s not good, and it did not work. One of your questioners said she used hydrogen peroxide on stains and it worked but did not accept the stain.

I’m using polyurethane over natural pine floors. What do you think of my mess? I think it will be okay if the stain comes out. I’m probably going to need to try sanding again to remove the vinegar stains.

A: At least you are not facing a chemical we know little about. I would lightly sand the marks and it should come out. Here is a suggestion for staining pine. I have found a great product called Waterlox. It is a Tung oil based penetrating finish. It offers the best way to stain soft woods. Mix 4 parts Waterlox and 1 part stain. Mop on and walk away.

Put oil on wood floor, now it’s tacky

Q: I have put some D***** oil on my wood floors and now they are tacky. What can I do to get rid of the tackiness? I have tried to buff with microfiber cloths, but it doesn’t seem to be working.

A: I think I would wipe it down with mineral spirits.

Related Q: How do I get an oil-based cleaner off my new engineered, dark hardwood floor? Help! It looks so bad!

A: Try a cleaner such as Bona Kemi floor cleaner, or Poloplaz floor cleaner which can be purchased online.

Yellow patch appearing on pine floor

Q: In our bathroom we have 30 year old pine floorboards that had previously been stained and varnished. I stripped the varnish off and sanded to reveal a nice distressed look. Then I used Sadolins floor oil. The result was very good. However, a month later I have a yellow patch appearing (about 8 by 8) and I can’t get rid of it. I’ve tried sanding, but the yellow only seems to get brighter. Do you have any idea what caused it and how to remove it? I don’t want to replace the planks.

A: It sounds like something was spilled on the spot and has either reacted with this oil finish or soaked past it and discoloured the wood itself. I would suggest contacting the finish manufacturer to see if they have any suggestions.

Adhesive for splits breaking off wide pine floors?

Q: My house has wide pine floors and several of them have partially split along the long side, right next to the gap from an adjacent board. I am afraid of one of these splits breaking off completely. I am unsure how best to repair this. I would be happy to send you a photo.

A: Do you have any way to inject some adhesive under this cracked piece?

Follow-up Q: I think I could get something under there. Maybe some clear epoxy. Can you suggest something?

A: I’d like to suggest Gorilla type adhesive except in this case it worries me. It expands as it cures. I’m afraid if this split edge is just hanging on, the adhesive will actually push it up and we will have made the matter worse. If the gap is wide and deep between the boards, you may have to pack something in the gap to prevent the glue from running away. Cyano acrylate (from Lee Valley Tools) sets up in seconds. It would be ideal if the adhesive bottle also came with a long nozzle allowing you to direct the adhesive sideways into the groove on the board. (assuming it is the groove side that has the split). Fast setting with a nozzle, and best to stay away from expanding foam urethane. Some wood glues set in about half an hour. That might work too.

Follow-up: Thanks again. I’ve attached a photo but its a bit difficult to take a picture of. I had read about the gorilla glue and I thought that the expansion might help as the splits go downwards when stepped on but maybe the expansion can’t be reliably predicted or controlled. I have previously tried inserting some wood matchsticks (not the striking end) and some wood glue but I was hoping there might be something better. I’ll look into the the cyano too as you suggested.

Repairing burn marks on floor

Q: I had to belt sand a burned oak floor. In spots I got the stain correct [matching golden oak], now I want to feather the urethane edge. The original floor is 4 coats of urethane I think. The divots were 1/8 deep.

A: I haven’t seen what this burned area looks like but if it was bad enough, I may have opted to replace the damaged boards. In coating, you are better off isolating entire boards involved in the repair. Sand coats of finish on entire boards, remove dust and use painters tape along edges of those boards. Apply a thin coat and remove the tape immediately. Repeat as needed. It’s not likely this will be unnoticeable when dry. It time, with some wear it will look less noticeable.

Follow-up: Thank you for your input. I am 62 and I have worked with much wood and finishing. This task is rare and I have not been able to find anyone who has done a repair like this. I will keep you informed when I get it completed. The floor got burned in spots, 2 spots deep, and the rest splattered they are lucky. The wood grain is too beautiful to remove and replace, as it was laid with care and matches. I belt sanded it down, and I have stained it to match, which I got it 90% on. The edges are what I will work on today, when finished with polyrethane, many coats, I will wet dry the final out, and bring the area up. I may end up just sanding the entire floor.

A: Ha, I’m 62 also. 63 in March. I’ve done lots of patch repairs. The older the existing floor is, the more difficult it is to get a good colour match. Plus sanding out a burn 1/8″ deep? You would have to feather sand out from there much further so it doesn’t look like a trench or trough. I would apply thin coats of finish on just the affected boards as mentioned. Even with this, the sheen of the coating is likely to not be exact. If you get the stain looking real close, perhaps you can just screen the entire floor and coat the whole thing? Do a couple of test areas to make sure there are no contaminants which would reject adhesion. I have been using Poloplaz Primero for quite a few years now. It rolls on beautifully and is as close to a no failure finish I’ve ever used. There Supreme is also very good but doesn’t dry quite as quickly.

Let me know how it turns out. Tricky work for sure.

Similar Q: I hope you can help me out. I have a hardwood floor and a ceramic heater fell over and heated up the floor to the point of slightly darkening the wood. Is there anything I can do short of replacing the darkened area?

A: You could attempt to sand to clean wood first but restrict this to the entire boards affected. If this is a factory finished floor though you are best to change the boards.

Floors wrecked by former tenant using some white substance

Q: I had a tenant living in my home and after they left I went to check the apartment.. there’s a nasty aroma and a white substance poured over all the wooden floors throughout the house. It was purposefully put there and the wood was ruined, and all broken apart. Can you tell me what substances can cause wood to be like that and how to remove it?

A: I don’t know. Could it be some type of acid? You could have a sample tested at a lab.

Solvent which was designed to remove glue also softened the finish

Q: I removed the carpet and pad from a hardwood floor, but there was carpet glue all over it. I purchased a solvent which was designed to remove the glue but it also softened the finish in some places and made it tacky. What can I do to fix those spots? Can I put a coat of finish over them?

A: I would give the stairs a good rub down with some fine sand paper and apply a thin coat of finish.

Small indentations in the finish

Q: We recently installed some hardwood floors out of old gym boards. We glued/screwed and plugged them. After banging them up to give them a beaten look, they were stained and finished.

We love the look, but recently found that a folding chair left in place for the weekend has left about 40-50 small crescent moon indentations in the finish for each leg in about a 10 inch radius circle. Some of them are even deep enough to depress the wood. What is the best way to repair this sort of problem? Can I give it a light scuffing of a sanding and then re-apply another coat of finish?

I’m not overly worried about the dents in the wood as the floor has already been distressed, it’s the obvious indentations in the finish that catch the light at the right angle that make it look awful. Any guidance is appreciated. Thanks.

A: I don’t think there is any way to hide these dents short of sanding/scraping them out and staining, finishing the area again. You could try filling them with wood filler, staining them and applying more finish. The lower the shine level in the coating the better is the ability of the finish to hide defects.

Follow-up Q: Thanks. Unfortunately I was hoping to avoid having to re-stain the wood. The majority of the dents are relatively shallow, I’m pretty sure that most don’t go through to the wood and are only on the finish. Do you think it would be worth just trying a light sanding and re-finishing first and if that bombs then to re-stain? Or would that just be a waste of time and money?

A: You could certainly try a light sanding of the area. It is the least intrusive approach. You could tape of the entire boards of the affected area, buff and coat just those boards and then remove the tape. It’s worth a try.

Sealer or wax that might hold a splinter in place?

Q: I have maple hardwood flooring in my foyer. One of the boards has a small split and has a small piece that catches on the swiffer when cleaned. What can I do to prevent this from getting worse? Would be hard to replace a center piece about 3″x18″? Any kind of sealer or wax that might hold the splinter in place to prevent it from breaking off?

A: There are several different types of adhesive you could try. I would apply tape around the split so as not to get the adhesive on the rest of the board. Cyano-acrylate can be purchased from Lee Valley Tools, called Hot Stuff. With an accelerator it will harden in about 5 seconds. Without it takes about 30 and dries clear. Some other wood glue and liquid polyurethane adhesives such as Gorilla glue will expand as they cure, so you would have to cut them back flat with the floor surface after they dry, but they accept stain. You don’t want to get that product on your skin.

Related Q: One or two planks in our hardwood floor have splintered along the edge, leaving a small uneven gap. Is there a recommended procedure for filling this with wood filler? Do you recommend a particular product?

A: For small spots like that there is a product in a tube called Color-Rite. It comes in hundreds of tones and is much like caulking. It won’t crack out after it is dry and is water clean up until then. Some hardwood retailers carry this product such as Woodchuck Flooring in Toronto. They also have a web site. Find the closest tone and apply. Push it into the gap with your finger. You may have to do this more than once if it is a deep space and the product shrinks.

Lots of loose boards in engineered wood floor

Q: What happens to an engineered wood floor when a home is left unoccupied with no power/AC for a year? I’m about to buy a repo with lots of loose boards. Is this the reason why? Too dry and shrinking away from the floor glue? I know they used glue originally via the exposed edge at dishwasher area.

A: I don’t think that is the reason. If it is a repo, the owner may have been short on money and this was a DIY project. He may not have used the correct trowel to sped the adhesive (too small a notch) and probably didn’t roll the floor so he got inadequate grip on the back of the boards with the adhesive. That is my theory.

Follow-up Q: Is there any solution short of replacing the boards? I may be able to remove and re-glue some areas that are totally hollow sounding but there are places that have pockets that are loose. How do I fix these?

A: Bostik makes an injectible adhesive. Drill a small hole and inject. The adhesive will expand and fill the void below the floor, gripping both the sub floor and finished floor.

Cracking noises when we walk on engineered wood floors

Q: I had engineered wood floors installed almost 2 years ago. The floor continues to make cracking noises when we walk on it.

What is causing the cracking sounds and is it due to faulty installation?

Also, the installer used silicone caulking to glue the bottom of the baseboards to the wood floors, is that normal?

A: It sounds like the surface the floor was installed on may not be totally flat, so when you walk on the floor it moves up and down causing a rubbing between boards or panels. I doubt he was attempting to glue the base to the floor.

Again if the sub floor was not flat, there would be spaces under parts of the base. He may have used caulking to fill that in. Also, if he felt a draft coming under the base, that would be another reason for the caulking.

Related, not the subfloor Q: Since the day they were installed about six months ago, our hardwood floors ‘crackle’ when we walk on them. (It is definitely the boards themselves, and not the subfloor squeaking.) It occurs all over: in the living room, hallway, etc.

This is a second floor installation. The first floor is fully finished and heated. Living room humidity ranges from about 35 to 55%. Our contractor says floor is not perfectly level, but he’s seen worse (and never had this degree of crackling.) Suggestions?

A: I would let the floor go through a couple of seasonal cycles. I installed one floor that had such a tight fit on the tongue and groove, it was difficult to work with. For a number of months it wold make cracking sounds all on it’s own. No doubt, this was from slight movement as the floor reacted to humidity conditions in the home. It adjusted in time.

Wax finish gets dull fast

Q: I recently refinished the 80 year old white oak floors in our family and living rooms. Having used a drum sander and edger in my first attempt 11 years ago, and finishing with a water-based polyurethane, the innumerable chatter marks and other disastrous mistakes encouraged a new approach this time around.

First, I opted to use the Random Orbit sander, as the tool rental clerk suggested it to be more forgiving than the drum. This proved wise, as I was extremely pleased with the smoothness and lack of sanding marks visible after I had put the final wax finish down.

The trouble that I am now experience must be due to my choice of wax or my finishing technique. The product I chose was H*****’s Feed N Wax, a combination of beeswax, carnauba wax and orange oil. It produced a splendid coloration and pulled out the natural grain of the wood. Yet, the finish is somewhat less dull in some places than the promised satin matte. Furthermore, the high traffic areas are seeming to lose their sheen almost immediately, while less travelled areas show foot and shoe marks that can be removed by light buffing.

I applied one thick coat with a lambskin applicator, wiped the excess oil up after the suggested 20 minutes and buffed vigorously with a 13′ buffing machine. What can I do to produce and maintain a consistent shine, while not needing to follow up each footprint with a soft rag?

A: I’m afraid I don’t have much advice for you on this one. This is why most people don’t want a wax finish. It takes constant maintenance, scuffs easily and gets marks from spills. I would suggest speaking with the company who manufactures the wax finish you applied.

Popping sound in hallway one year after install

Q: We live in a condo on the 10th floor. We put in engineered Brazilian hardwood. It’s been one year to the date. Now in one small section (hallway), when you step in a few spots there’s a popping sound. Sometimes it is very loud. What causes this and what will fix it?

A: It sounds like some expansion has occurred. Is it possible there is a leak someplace? You could have someone come in with a meter and check for moisture levels. You may simply have to buy a hygrometer (from an electronics store) and monitor the indoor relative humidity. You didn’t say if the floor was glued down or is floating. If it is a glue down, you may need to buy some adhesive that is injected through a tiny hole in the floor. this will expand and fill any dip in the concrete beneath if that is a problem. I believe Bostik makes such a product.

Cracks at some joints after HVAC was turned on

Q: I had my 225 year old heart pine floors refinished (sanded, caulked and finished with water base satin finish). The job was done two weeks before HVAC was turned on. I now have noticeable cracks at some joints. My contractor says that it is because the HVAC was turned on causing the wood to dry thereby causing cracks. The floors have been in this environment for 25 years. What is your opinion?

A: When I lived in Toronto there was oak strip in the dining room which was 70 years old. One winter was particularly cold and long with the snow starting in early November and going right into April. So the furnace had been running for quite a long time. I noticed some gaps appearing in this floor that I had never seen before. I got the furnace installed humidifier running and the gaps went back to the way they were. So, it doesn’t matter how long a floor has been in a house, the wood still reacts to the environment. The wider the plank, the greater the expansion and contraction. I think I would buy a hygrometer and keep an eye on the relative humidity in the home. 70-75 F with RH of 35-42% would seem a good environment.

Floor both cupping and gapping

Q: I have 2 year old maple 3/4 inch floor with varying widths. It has had cupping in some areas and ugly cracks between the wider boards. Humidity always checks out at about 45. First floor rooms with finished heated basement below. 15 Year old house. Floors over vinyl flooring in one room and particle board in two others. Moisture Barrier in all rooms. Installer will come back to refinish for free in driest time of year: Feb-March. Will this solve the problem? Advice on type of finish? Would a filler pop out in summer months (in Wisconsin)? Would staining the maple make cracks less noticeable? Does maple stain okay? Thanks for your response.

A: Strange, you seem to have two opposite conditions occurring in different areas. Cupping usually indicates moisture imbalance from beneath the floor, ie too much moisture movement through the boards from bottom side toward top. Gapping indicates shrinkage or lack of moisture. What isn’t known is whether the flooring was acclimated to the house before installation and if both the sub floor and maple were checked with a moisture meter first to make sure the difference was not more than 4%. I wouldn’t be concerned if the sub floor was more than 4% drier than the maple but if it is more than 4% higher that could be a problem. In the areas where there are gaps, is it possible you have heating ducts running along the ceiling in the basement between the floor joists?

I wouldn’t have an issue installing over vinyl flooring provided it isn’t the thick, old ‘cushion’ floor which could allow movement and flex of the floor and loosening of the fasteners. When you say particle board do you mean chip board or OSB? Not a great fan of installing on this because it tends not to do a real good job of holding the flooring down near as well as plywood. Not saying this is the cause of any issues, only that it doesn’t hold cleats and nails very securely. If you have any movement between boards any wood filler applied will crack out.

Maple can be stained of course. I’ve done my share. It would help to make the cracks less noticeable I think because maple is generally so light coloured with such tight, pencil thin grain that any imperfections in the floor surface are immediately apparent. It isn’t the nicest wood to stain however. It can tend to look somewhat mottled or blotchy because of the wide swings in density from one spot on a board to the next. As long as you are aware of this beforehand and can live with that then there is no issue. I prefer sating polyurethane and Poloplaz Primero is the best I’ve ever used. It does smell while drying.

Follow-up Q: Thank you for your prompt reply.

The man who installed the wood has agreed to come back and refinish it. As we are now in the winter the cracks are large all over not and just one area. I think the problem may be that we have different widths. The wider crack, the narrowest cup. Perhaps they were not properly acclimated when installed. At this point I am rather weary of dealing with this floor. It is only two years old and started having issues within the days of the install. I was thinking of just pulling it out and replacing it with something else. Is that crazy?

A: It would be a shame and a waste to rip out and discard what is basically a new, 3/4″ thick floor. I assume this is factory finished maple so they are going to have a major job sanding it and dealing with the micro bevels. I’d have them do that or if you don’t want to deal with it, if you can arrange for a payment to cover the sanding, take the money and live with the floor for now. Give it a year or so to see if these gaps close and it flattens out at all. I went to look at a maple floor installed in a new house in Welland, Ontario several years ago. Very much like your situation. Maple installed on chip board. Fairly bad cupping so guaranteed once the moisture content stabilized they would have significant gapping too. The builder and someone from the warranty company said this was considered normal. Wow, I couldn’t disagree more. New construction is particularly risky because at one point the entire structure was open to the elements and was wet. This takes time to dry out. So installing hardwood floors until the building is dry is not a good idea. But they do it anyway as if it is an assembly line house and they have to throw it up and sell it fast.

Follow-up Q: Thank you for being so helpful. Our wood was unfinished / finished on site. I do think there was a problem with the wood since we had trouble right away. If we sand where it is cupping will it appear concave later when it dries out? Can the gaps be corrected? From what I read, filler, etc. is only a temporary fix.

A: The guy doing the sanding should take multiple samples with a moisture meter to make sure the wood is within specifications before sanding it. Once he sands it the edges of the boards will be a bit thinner than the center and if it isn’t dry the boards would then likely crown where the center is raised up higher than the edges. I’ve never found a filler that can never crack out. Thinking it through though, you don’t really want anything between gaps that might be an impediment to the wood swelling slightly under higher humidity conditions because then you would likely end up with cupping again because of stress on the board edges. Normal gaps are usually considered to be about as wide as a dime. If there are any that are much larger than that a few of those could be filled, here and there. A polyurethane adhesive such as gorilla glue could be used first. It expands as it dries but is easy to sand off the floor surface. After it is dry it won’t pop out and it can be cut back to just below floor level and a wood filler applied over top of it. I would only do this in random, large gaps. Not over the entire floor.

Is there a way to fill in dips?

Q: I put down some 3/8 engineered flooring on a slab with glue. In the rush to get the job done within the time I had allowed, apparently two small dips in the slab were missed. Now there are two areas, about 10 square inches, where the floor is just floating over the glue. If you step on the area, the floor dips, adheres to the glue for a moment, and then pops back up. Is there a way to fill in underneath these small areas to stop this problem, without pulling up a lot of floor to get to the spot?

A: There are indictable adhesives on the market. You drill a tiny pilot hole, insert tube nozzle and squeeze. The adhesive will expand under the floor and fill the cavity. I believe Bostik makes just such an adhesive.

Related Q: My dad and husband recently installed an engineered walnut floor in my kitchen. They ended up with a low spot, due to an uneven sub floor, resulting in the occurrence of a “popping” sound when you walk across the uneven area.

This, unfortunately, is a high traffic area. What is the best way to correct this problem?

A: If they had put a nail in the tongue at that spot it likely would have pulled the board down and helped prevent the sound. But, stuff like that happens.

How about this: there are injectable adhesives you can use which can be squeezed through a tiny hole drilled through the board and the adhesive will expand into the space under the boards. If you have access from the basement, you could even do this through the sub floor. That is one idea. You might find that this annoying movement will come and go.

Removing green layer under cement board

Q: The house we purchased recently came with heart pine floors in the living room. There’s carpet and tile in the other rooms. We found out that the wood covers the entire house. The carpet was easy to take out, but in removing the tile, we found this paint/stain green layer under the cement backer-board. It’s not an adhesive since the cement board comes off fairly easy in between screws. Any ideas what this green stuff might be and a good way to remove it? There’s about 500 square feet that I’ll have to use a hand sander on otherwise. Thanks for any suggestions.

A: I’ve sanded many softwood floors that were very old and painted. I’ve never come across green. In any case, the floor probably needs to be sanded to bare wood and re-finished. You may want to consider hiring a professional for this job.