Removing glue from cement

Q: I’ve recently ripped up engineered hardwood that was glued to plywood. We also ripped up the plywood (there was so much glue it pretty much came up with the hardwood). The plywood was also glued and screwed into the cement.

We’ve gotten most up but are having issues with the remaining glue. There are some spots with wood still stuck to the glue and we cannot get it up! we’ve tried glue gone, scrapping, paint thinner and hot water and these small spots of gluey wood don’t seem to budge! Any suggestions?

A: Bostik does make an adhesive remover that would likely soften it. You could also rent a machine to help chop up the remaining ply and adhesive. It’s a nasty job.

Solvent to soften black rubber carpet underpad?

Q: I am trying to remove a solidified layer of black rubber carpeting underpad from a hardwood floor.

Can you suggest a solvent to soften it? It seems to respond to acetone-based nail polish remover, but I would need gallons.

A: If it responds to acetone, you can buy that in larger quantities at any paint store. However, be aware that the acetone will also remove any varnish or polyurethane that may be under the padding.

Have you tried scraping it off in hardened state with a drywall trowel or scraper?

If it does chip off, the way to go may be to leave it dry and work at 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.

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.

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.

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.

Silicone stuck to laminate wood flooring

Q: I have silicone on my wood flooring laminate (the installer of our wood stove put a mat down and siliconed it to the floor). How can I remove the silicone without damaging the laminate?

A: That is brilliant. I wonder how he got such an idea? I assume you have tried to peel and pick it off and it won’t come off? Denatured alcohol is a good agent to remove contaminants. I would try that.

Floors sticky after being treated with insect killer solution

Q: I had worms in my old hardwood flooring. They were treated with some kind of insect killer solution, and after 2 weeks the floor became sticky. Should I sand it down and stain it or is there an easy solution to my sticky floor problem?

A: I think I would be asking the person or company who treated your floor how to neutralize and remove the residue. And I don’t think I would be handling it, walking on it, letting children or pets near it until this is resolved. It might be as simple as wiping it down with a wet cloth but check first and don’t be applying any other type of chemical until you know what the outcome might be.

Rough spots from vinyl adhesive

Q: When I bought my home 7 years ago there were vinyl stick tiles on a 3×3 area in front of the door. I removed these tiles years ago. I’ve done all the steps required to refinish the wood floor. I used 50 80 and 120 grit to prep the floor. I’ve stained the floor. Now that I am applying the poly, I notice rough spots where the adhesive was on the floor. How do I remedy these spots?

A: Did you fully remove the adhesive to clean, smooth wood? You should be applying 3 coats of finish at any rate after sanding with fine sand paper between coats. Hopefully this will result in a smooth floor. I think you were fortunate to be able to rough off the mess with 50 grit.

Follow-up Q: Thank you for your response. I went ahead and spot sanded the areas with 120 and my orbital palm sander. It seems to have worked so far. I just reapplied a coat of sealer and so far so good. When I originally removed the tiles years ago I used an adhesive remover and didn’t even see the affected areas until I applied the first coat of sealer. There were other areas along the same wall where there was still adhesive on the floor when I sanded yesterday and those spots are not visible. I’m wondering if the chemical I originally used to remove the glue damaged the wood to an extent that I had to sand deeper in those spots.. guess I’ll see when this coat dries.

A: You would think and hope after years of exposure the chemical you used would have neutralised by now, but you never know. As long as you have adhesion with the first coat, you should be okay from here on. Just make sure to thoroughly abrade the finish and clean well before applying another coat. Are you using water borne or solvent/oil based finish. If it is water borne you should be able to apply succeeding coats without buffing if applied within a specified number of hours, but check the documentation or label before doing that. Oil based should always be sanded first to completely scuff up the coating.

Follow-up: It’s a water based coating. The directions say 2 hours between coats. I did my dining room floor several months ago and had great success. It’s this one area that is troublesome. After sanding again and coating, some of the spots are gone but some came back. Definitely a learning experience. Thanks again for your input.

Wood floors covered by a layer of gunk

Q: The house I live in has hardwood floors with a polyurethane finish. The finish is over 30 years old and the floor is stained black with dirt. When I try to clean it I am able to peel a layer of something off. I would like to know if this layer is the polyurethane, and if so what should be done with the floor?

A: What are you using to clean this floor? I can’t even imagine what would cause a finish to just peel off a floor after 30 years. If there is an adhesion issue it generally will appear with a few weeks of application. Perhaps somebody applied something else on top of the polyurethane and that is what is peeling off?

Follow-up Q: For years we have used mop and glow, oil soap, and now we’re using reguvenate. When I wet or heat the floor I can peel it very easily. It peels like dead skin in big strips.

A: Sorry. All treatments not to use on a polyurethane top coat. I would look at who have two cleaners, one being more agressive than the other. I had one lady with a similar issue to yours. They got some cleaner and buffed the floor with a car buffer and soft pad with similar results as you describe. The stuff peeling off in strips. Once you get it all off depending on the condition of the old finish, you may want to have another coat applied but only if needed.

Follow-up Q: Is the stuff peeling off the finish? And if it’s not should I peel it off or should I leave it on to protect the floor from whatever. I won’t be able to hire anyone or redo the finish. I have a really sick person living in the house and I can’t redo it.

You said your floor was black with grime and dirt. If you want it clean you will have to remove it. The products you applied to the polyurethane attract and hold such grime. You did mention applying heat to it. Heat from what source? I would think you would want to remove all that mess down to the old poly finish but you are there. You can see the floor and you can see what it looks like beneath the film that has flaked off.

Follow-up Q: The heat is from a steam cleaner mop.

I need to know if the grime is better to be left on. And in the long run it will keep the floor in better shape. Or should take I it off? Underneath there is no finish. Will the floor get worse and demand a job to fix it later on? Which is better to keep the floor lasting longer?

A: Wow, not a good thing to use either. Water in any volume is not a friend of wood. Steam is worse.

It may be best for you to leave it. There are cleaners, cleaning solutions that will likely remove all this mess. But only you know what was on the floor and what condition it was in before you started applying mop and glow and oil soaps. There must have been a reason you applied such things which only makes it worse.

Follow-up: Thank you so much for reading everything and answering back. I’ll take everything into consideration.

Sticky film from rug

Q: I just moved. My new hardwood floor was left with a light sticky film from an area rug that the previous owner had. How can I remove the sticky residue? It is not thick, it is just slightly sticky and when light shines on it it looks like a light whitish film is on the floor.

A: I would think a polyurethane cleaner would work, provided that is the type of finish on your floor, not oiled or waxed. Poloplaz has their version of such a cleaner as do Basic Coatings, Boa-Franc (mirage) and Bona Kemi. Poloplaz also has an even stronger cleaner called tie tac.

Whoever put the carpet in glued it down

Q: The house I bought has old carpet in the bedroom. I lifted the carpet and found hardwood floors. The problem is that whoever put the carpet in glued it down! The carpet comes off easy enough, but the underpad is glued to the floor. The carpet looks like it is 20-25 years old. How do I get the glue off the floor? Do I have to sand and stain the floor? Should I just by a new carpet and cover it up? Help!

I am wondering what kind of fool glues carpet down over hardwood?

A: Someone who doesn’t understand the value of a wood floor and hasn’t a clue what they are doing. Sounds like a description of quite a few (unqualified) DIY persons.

The only practical way I know of to remove this is to sand it off. I would recommend a professional. You will have to decide beforehand if the floor is thick enough to take an aggressive work out, which will be needed. Also, how tight or how many gaps are in the floor? If there are a lot of gaps, it is unlikely you will remove the adhesive from between the boards. Carpet is a cheap, temporary solution. If it seems ill advised to try to sand this floor, removing it and installing a new 3/4 thick floor is the long term solution.

Related Q: We tore up our carpet to find that we have nasty yellow/tan glue over our hard wood floors. We have scrapped, planed, and started to use some paint thinner. Could we use a drum sander with 16 grit paper to remove this glue?

A: You know about 16 grit sand paper? Well yes that would be the way to do it. I’ve done my share. Keep in mind the thickness of the floor can help determine if doing this is worth while or not. By thickness I am particularly referring to the thickness from the top surface of the board to the top of the tongue and groove. If that gets thin the wood will start splitting.

Follow-up Q: I’ve spent many hours crying over this project I really wanted.

We attempted 40 grit and it gummed up. So I didn’t know what we should use. They are original hardwood floors, I will check the wood depth in the vent. What is a good “thickness” that 16 would be acceptable. I hand planned all the glue off in the dining room. I don’t think my arm can handle the massive living room.

A: You may have wanted to hire a professional for this job, but you are into it now. If this is old style strip, you only have 3/8 or half inch from top to bottom. The wear layer is much less than this. If you start seeing nail heads appearing on the board edges you are going to be about done with this floor. If it is 3/4 thick you should be good. Sometimes people do this sort of glue down over hardwood because the floor is in really bad shape. other times it is because they don’t have a clue what they are doing. Hopefully in this case it is the latter, not the former.

Removing soft putty from nail holes

Q: I used wood putty instead of a sandable wood filler on some shelves that I built and now I find out that the putty does not get hard. Ouch, my stupidity I know, but do you know of a way to remove the putty from the nail holes so I can then use a sandable filler and paint over? Thanks in advance.

A: If you are painting over the putty would it matter if it gets hard or stays soft? I would use a nail the same size as the hole to remove the putty if you wish.

Gyprock dust on new floors

Q: We have the same old issue of gyprock dust on new floors. I vacuumed as best I could and of course used a mop after, which I shouldn’t have! We have done our best to clean out the muddy mixture in some of the grooves. I wanted to ask.. seeing as we’ve done all that, do you think a coat of natural oil will improve the result? We were thinking that if we oil it and create some moisture some of the dust spots will reduce to a degree.

A: Drywall dust is very nasty as you know. I read of one case in the NWFA magazine of a prefinished floor newly installed in a house being built. The floors weren’t protected and a lot of drywall dust got between the boards. They decided to wet mop the floors which re-activated the drywall dust and caused the floor to cup badly so that they had to rip out the floor.

I’m assuming your floor is finished with a top coat such as urethane. In such a case, you don’t want to be applying an oil on top of that. Best bet is to get some proper cleaner for floors like this which leave no residue, do a good job of removing contaminants on the surface and evaporate away quickly. There are quite a number of such cleaners available and your local wood floor distributor should carry one of them. Either the cleaner from Poloplaz, Bona Kemi, Basic Coatings, Boa-Franc etc. Continue to try and remove as much compound from between the boards as you are able, perhaps using a crevice tool to increase and focus the suction. I would think that eventually any dust you can’t remove will eventually vibrate down to the sub floor.

Sticky residue from area rug

Q: I have an area rug that has been on top of a non-slip rug pad for a few years. The pad left a sticky residue on my wood floor and I was wondering what would be the best way of breaking down the stickiness so I can leave the floors uncovered?

A: You can try a polyurethane floor finish cleaner provided your floors have that type of coating. Products such as Poloplaz Hardwood Floor Cleaner, or similar from Bona Kemi, Basic Coatings, Min Wax, etc., most of which can be purchased from any local hardwood distributor. If that isn’t aggressive enough Poloplaz has a more aggressive cleaner called Tie Tac.

Removing glue from subfloor

Q: I removed glued down engineered hardwood and some glue was left. I am replacing the old floor with stapled down engineered wood. Do I need to remove all glue residue and if so, what is the best way to go about removing glue from subfloor?

A: There are adhesive removers, but if there is a lot to remove that won’t work given the cost. You are probably going to need a sharp chisel, a hammer and a pair of knee pads to remove enough that the floor is reasonably smooth.

Similar (Earlier!) Q: We want to remove a Bruce maple 3/8th inch hardwood floor that someone adhered to the subfloor with a glue or mastic. I have used a hammer and chisel. There is 1000 square feet to remove. I was thinking it might be easier to cut it out all together including the sub floor and start over. If we remove the wood and then end up with this glue all over the subfloor, I don’t think we can get the glue up to have a nice clean surface for the new wood…

A: I think you are probably right in your assessment. For the amount of slugging it will take to remove 1000 feet of this engineered floor and then have to rent a special machine to claw off the adhesive, you would be well ahead of the game to just cut it in sections right through the sub floor and start over. A bonus to this is you can check the joists for being level and if any shimming needs to be done you could take care of that too.

Related Q: Does glue need to be removed from the subflooring before the felt pad is laid underneath the hardwood flooring?

A: Well, I don’t know what flooring you are installing but in any case the sub floor needs to be fairly flat without significant lumps, ridges, etc.

Related Q: I am preparing to install a new 3/4 inch unfinished oak floor in a kitchen, dining room and hallway. I have removed an old laminate wood floor that was installed about 15 years ago. There is some residual adhesive left behind on the subfloor. Can I install over that left behind adhesive?

A: You can install over it provided it is smooth without serious raised, bumpy globs.

Black gunk like polyballs

Q: Every fall this hard black gunk appears in one exact spot on my hardwood floors. It appears to be coming up through the crack, and the only thing that removes it is my steam mop or a sharp blade. I’m not concerned about HOW to remove it, but more so about what it this black gunk and how do I prevent it from coming back?

A: I’m not certain but it almost sounds like you had your floor stained dark and some of the stain and finish seeped between the boards where, devoid of fresh air it has stayed soft and every once in a while squeezes up to the surface. However, this phenomena called poly balls generally occurs in spring and summer when humidity is higher and you can get some expansion of the boards.

As a side note, I would not recommend a steam mop be used on a hardwood floor.

Removing Applique from Hardwood Floor

Q: We own a rental and did work there recently. The tenants had put up a dartboard and put a Budweiser applique of some type, which is 4 inches by 12 inches, on the hardwood floor as the “throw from” line. Will this damage the floor? I tried to see if it would peel up simply (it’s about 1/16-1/8″ thick) and it wouldn’t budge. I don’t think it’s been down long. Will it damage the floor and should it be taken up as soon as possible and if so, in what manner? Any tips for removing applique? If the floor is damaged, any suggestions? Thank you.

A: I would take it up as soon as possible. I’d likely try to use a 10 or 12 inch flat blade trowel to get under it and scrape it off. You will likely have to find a solvent to dissolve the adhesive I think it was held down with. Any scratching of the finish will have to be buffed with fine abrasive and re-coated.

Spilled polyurethane on a Formica table top

Q: I have a spill of polyurethane on a Formica table top that has been there for several months. Is there any way to remove spilled polyurethane?

A: I would try an X-acto knife with a sharp blade and carefully slice it off. If you can get it down to the point where there is little of it remaining, the rest could be rubbed off with a cloth dampened with acetone.