Should all windows be left open during refinishing?

Q: I am scheduled to have hardwoods flooring stained and 1 coat of sealer tomorrow, but it is supposed to be only 40 degrees and rain, maybe ice. I understand that all windows should be left open. Do I need to reschedule for a warmer day in TX?

A: I disagree that all the windows should be left open regardless of the temperature. When applying any coating one thing that can really mess up the job is to have air moving across the coating before it has had time to flow out and set up.

You will need to have the house well above 40 degrees, and close to 70F would be more ideal. If humidity in the home is high, running a dehumidifier should help with that.

Is this shellac on my hard wood floor?

Q: I was hoping you could give me some advice. I rent an apartment which has nice hard wood floors. I have been here for 2 years now and have noticed the shellac (I think it is) is peeling off in spots. It is becoming worse and more noticeable. How can I fix this and prevent more shellac coming off? I want to take care of it before it gets worse.

A: If your finish is shellac it will dissolve if alcohol is applied. More than likely somebody has applied a coat of finish (polyurethane) over an existing coat without proper preparation to gain adhesion. The real solution is to remove at least that top coat of finish by screening with a polisher and abrasive screen, or more realistically to have the floor completely re-sanded and finished.

Mystery peeling around perimeter after 18 years

Q: We’ve had a decorative wood floor in our dining room for about 18 years. installed by a local guy, with pickled ash finish and a dark cherry perimeter. The wood was prefinished when we installed it. Today we picked up a cardboard box off the floor, and the finish seems to be peeling off the dark cherry. It doesn’t seem to be caused by the box (it was there for a day and was heavy, but no residue on it). The only thing I can reason is that we have skylights above the dining room and they are unobstructed to the sun, perhaps ageing the finish. What happened, and how do we fix it?

A: This is quite a mystery, isn’t it? The sun shining through your sky light didn’t peel the finish in 18 years and I know of no reason it would suddenly do that. The card board box wouldn’t cause this either. At least not on it’s own. Unless something was spilled inside the box or at some point the bottom of the box was set onto any chemical which would attack polyurethane coatings. Things such as strippers, acetone, perhaps nail polish remover? If this is restricted to one or two boards I would wipe them down with a wet cloth to neutralize anything which may be on the board. I would gently but thoroughly rub the entire board down with fine sandpaper or other appropriate abrasive. This scratches the existing coating allowing adhesion of a new finish coat. Apply a thin coat of polyurethane with the same level of shine. If a second coat is needed, repeat the process.

Greasy substance on unfinished floor

Q: I am about to screen/lightly sand my floors and apply a couple coats of polyurethane. I have done some years ago, but never had this problem: There is a greasy substance which has gotten into the oak hardwood (the finish has been worn off/there’s no sealer) and regular cleaning/washing did nothing to fix it.

How do I be sure to get it out before putting the new finish down? I don’t know if light sanding will remove it.

A: Are you saying the wood in that area has no finish and is totally exposed? In that case, it must be greyed and discoloured. If that is the case, you will need to make sure the wood is sanded clean.

If you are concerned about contaminants you could wipe the area down with alcohol (not Jack Daniels), perhaps apply a coat of de-waxed shellac and then coat the floors.

Dish out / raised grains

Q: I’ve been managing my floor company for some time. I have guys who do the work. I get the jobs, manage them. A problem keeps coming up after they poly the floor. I see raised grains all over the place especially with high gloss. How do I solve the issue? Thanks for your help.

A: What kind of finish are your guys using? Raised grain generally means moisture right? Such as water popping a floor prior to staining. It raises the grain and the floor feels a bit rough. I’ve seen water borne finishes and some water borne sealers cause serious grain raise. Nothing that a quick buffing won’t knock down. It should not occur after the initial coat in any case.

Follow-up Q: Oil base poly with Dura seal stain. Does it make sense that it could be the machine is not balanced? Images attached.

A: I’m seeing ‘dish out’ of the soft grain. Hard to avoid that with a heavy grained wood like oak. I’ve read using a 3 disk polisher-sander like a ‘trio’ can help eliminate it. After more than 40 years and at age 62 I don’t think I’m in the mood to buy another toy like that, never mind carrying 175 piece of equipment in and out by myself. I think I’d try and move people away from the very shiny finish. Dark stain and gloss? It is like shining a spot light with a magnifying glass on the floor.

It doesn’t hurt if you suspect a drum issue to find some place you know is flat and level. Remove the belt from your machine and lay a used 100 grit down, grit up of course and gently bring the spinning drum down on it to see how much of the drum is initially making contact. The stain job itself looks good.

Lap marks in amberized sealer

Q: I am in the middle of refinishing a 75 year old white oak parquet floor. The customer wanted the older yellowed look and opted for amberized sealer. While applying I noticed I left a large 10 inch path a few feet long where it wasn’t smoothed enough and now shows a line. I applied a second coat of amberized sealer and am waiting to see if it disappears by tomorrow morning. If not, how do I get these huge lap marks out of a water base amberized sealer?

A: I’ve never used amberized water born sealer. I would call the manufacturer of the finish. However, especially being white oak, isn’t it possible the streak is a tannin reaction? I suspect you will have to scrape the mark out and try that spot again.

New wood is shiner than the old wood after finishing

Q: I have a original 1957 wood floor that we sanded. We had to replace some parts due to damage. When we put semi gloss poly on it the new wood is shiner than the old wood. How can we make it come out all the same?

A: It should all be the same if you stirred the finish well. It could be the old wood is now well dried out and more porous than the new. You have more of a build on the new wood than the old. Apply another coat. Satin also looks very nice and would be closer in look to a floor from 1957 where wax was common. In any case make sure satin or semi gloss are stirred well, not shaken. This will evenly distribute the paste in the mix which determines the level of shine.

Oil based polyurethane finish looks “dimpled”

Q: We recently had our red oak floors refinished, using Min-wax Red Oak color, and we chose oil based polyurethane. We contacted the refinishing company after the third coat of polyurethane was applied because we thought the semi gloss sheen looked somewhat cloudy where the light hits it, but clear when standing directly over it. Is this normal for semi gloss finish?

Also, I’m not sure what the correct word is, but dimpled comes to mind. The poly appears to be dimpled, or lightly bumpy, meaning not totally smooth. Is this normal? It’s not referring to sand or granule stuck in the finish, but a subtle dimpling across the entire floor.

The room was kept at 60 degrees for drying, and one day in between each coat. The flooring company explained this “dimpling” was normal, as the floors take 6 months to cure and therefore appear smooth, I am wondering if this sounds accurate.

A: The finish may have set up too quickly, not allowing it to flow out level.

I don’t know what finish was used but all except gloss have a paste (silica) added to reduce shine. I don’t know if something was up with that – not mixed well enough or an issue with the paste settling to the bottom of the film.

I had that happen once years ago. But since using Poloplaz Primero I’ve never had any issues. It is an excellent coating.

Blending finish overlap “ridge”

Q: I just redid my hardwood floors and they turned out great except for one area. There is an overlap ridge and I would like to know how to get rid of that ridge so it blends better. It has been sitting for almost 24 hours.

A: Are you saying this is with the finish you applied? If so, it sounds like probably a water borne urethane which sets up very quickly generally. You could try lightly abrading (very fine sandpaper or an abrasive pad; don’t use steel wool with water borne coatings) the entire boards affected, taping off the boards involved. Apply another thin coat and immediately remove the tape. If that doesn’t work you will have to re-coat everything. Remember, thin coats are always better than thick ones. All finishes have a recommended ‘spread rate’ such as 500 sq. feet per gallon.

What if I cannot remove all the old stain?

Q: What happens if I cannot remove all the old stain from the floors? Do the floors have to be sanded to absolute perfection, or can there be slightly different shades?

This house is very old and I don’t want to stain the floor, I just want to polyurethane.

A: If a floor has been stained in the past, it is near impossible to remove every trace from the heavy, soft grain. If such trace amounts remain, it doesn’t detract from the overall look of the newly finished floor.

Related Q: I had #2716 dark walnut on my floors, but I am now trying to sand it off. A lot of the stain is down in there still. What color of stain would be able to cover over it? I don’t want to go too light, but don’t want it too dark either.

A: A professional flooring contractor, both fully trained and equipped would have no issue removing all but trace elements from the heavy grain, after which the floor could be successfully stained any colour (except a pastel colour) without any real noticeable difference.

Milky marks appearing in finish of exotic wood floor

Q: We have Brazilian cherry floors with Swedish finish, installed in 2004. There are milky marks appearing in the finish. They now look like tread marks from athletic shoes. We don’t have any shoes that match the pattern. Any clues to what is happening?

A: I don’t have a great deal of experience with exotic woods such as Jatoba. To tell you the truth, I try to stay away from them.

I know it can change colour rapidly and in fact have seen it.

I’ve also heard that white marks can appear in some batches of Jatoba as an interaction with extractives in the wood and solvents in floor finish but I don’t know why it would take this long to appear if that were the issue.

Finish peeling due to too many coats of stain

Q: We really need some advice. We just moved into our new construction home about a month ago. The moving company used packing tape to tape down blankets to protect our newly finished hardwood floors. When they pulled off the tape, big sheets of the polyurethane came off. Thinking it was just an issue with the adhesive on the tape being too strong, the floor guy came back and “redid” those areas. However, we have noticed that wherever our dog (about 50lb and nails always clipped) has made any scratches (even slight) in the floor, the polyurethane is flaking off. You can literally peel it off with a fingernail. We have had dogs before on other hardwood floors, and while they may scratch it, the clear coat has never flaked off like this. We have wide plank, new heart pine. It was stained with 3 coats of Dura Seal Dark Walnut stain. They used 3 coats of Gerner Clear Satin polyurethane. It was sanded in between coats. Any guidance you can give us as to why this is happening would be greatly appreciated.

A: This issue is definitely not the fault of the tape. I’ve done tests on boards I’ve stained and finished with a variety of tapes including Gorilla tape, pressed onto the boards and left 5 days. I removed the tape after that with no issues. I have to ask why your floor guy applied 3 coats of Dura Seal stain. I’m afraid to apply two coats in case the first coat of finish isn’t able to reach the wood to gain a bond with that. 3 coats? Wow, I’ve never heard of that and as you can see, it isn’t a wise thing to do. If they wanted a darker colour they perhaps should have considered water popping first which opens the wood grain for a darker, more consistent colour. The only way to fix this I’m afraid is to start over.

Follow-up Q: We did 3 coats to achieve a darker color. 2 coats wasn’t enough to achieve the color we wanted. I’ve never heard of water popping. Can you explain that please?

A: It is easy. After all wood has been completely sanded and prepared with dust vacuumed up, wet (not soak) the surface of the floor with warm water. It doesn’t have to be warm. Don’t miss any spots. Allow this to completely dry and start staining. Do not drag or scuff your shoes on this lest it close up the grain in that spot and you end up with a light spot. That is all there is to it. If that doesn’t give you a dark enough colour then go with something darker. Final sanding should be finished with 100 grit and not finer than that. If the wood is too smooth you won’t get any stain penetration and the colour will look awful.

Follow-up Q: So, in your opinion, too many coats of stain were used causing the polyurethane to not adhere properly? And our only option is to start over completely?

A: If each coat was lightly sanded between each coat then that would appear to be the reason. It sounds like it is peeling, not between coats but right off the stain. There is no other way to fix it I’m afraid.

Installers added a coat of finish to prefinished floor

Q: I recently had new hardwood floors installed. They are pre finished flint maple pergo. The guys who installed recommended putting a poly coat down to protect them a bit better since we have a dog. We did the first coat, and it’s peeling in spots. We screened the floors. Will this help for the second coat?

A: We are talking about a real wood veneer and not laminate, correct? I would never suggest to a home owner to try to coat an engineered floor or anything factory finished. For one thing, they use finishes which are formulated to be abrasion resistant which makes it difficult in the extreme to impossible to adequately abrade the finish so as to gain adhesion. Their are chemical preparations designed to help with this, though I’ve never used them. The fact you have peeling spots proves my point. If the surface wood veneer is thick enough you are likely going to have to have these floors sanded to clean wood to fix this. I would suggest you contact Pergo and ask for their advice. I’m sorry this has happened to you. Always research first

Follow-up: Thank you for your quick response, I appreciate it. It is real hard wood yes, not laminate. I will call them today. My fingers are crossed that this is not the case. I followed what are flooring guy told us to do since he is the professional, but you’re right I should have researched.

A: I hope it works out for you. Beside the inherent risks in undertaking what you have started, even for a professional there is another issue that calls into question the advice you got. If a floor has an inferior finish to what you have then it might make sense to apply a better quality coating over an inferior one. This would be an upgrade. It is highly unlikely you would have access to a finish of this nature, so what has actually happened is you have given your new floors a down grade. Sad but true. In a certain sense, it’s like buying a beautiful new couch and leaving the shipping plastic on it to protect the fabric.

Follow-up: As suspected abrasion seems to be the culprit. I called the manufacturer and was told the exact finish they use. An aluminium oxide poly with water base. Oil was used on the floor. Trying to decide best move.

A: You can apply oil based over the water based. The problem is the aluminum oxide polyurethane is abrasion resistant. You said there is peeling in spots. How to know if the rest will fail also? Basic Coatings has a chemical prep you can use. Or you can get a roll of 120 grit and hand sand the finish thoroughly. I prefer oil based finishes. They are easier to work with and I like the look. However, typically water based can be applied consecutively without buffing between coats if applied within a specified number of hours which can be a plus.

Follow-up Q: If you were in my shoes what would you next step be? How would you handle this?

A: I would start sanding the finish with a fine abrasive. Every square inch. It will give you a good idea if you have a bond with the finish which hasn’t peeled yet. Once I’ve done this thoroughly, vacuumed up the fine dust and tack rag it clean, apply a thin coat of the finish of choice. You may have to do this twice. The main objective right now is to get a good bond between the original coatings and the finish you are applying.

Drying problems with the oil based poly

Q: After using B**** Coatings oil poly for years on floors without problems I was forced to return to D******* oil. Recently, I am experiencing drying problems with the oil based poly, in which I have cause to blame the company for changing the formula (to meet upcoming standards).

Have you heard any recent problems with the D******* poly on floors? Like not drying in ideal conditions, thus causing numerous problems? I may be forced to switch solely to waterborne, but worry about their past problems, like elasticity (too hard and cracking), not enough open time to apply and allow bubbles to pop, shelf life, etc. What do you think?

A: Isn’t our job great fun, especially when regulators start screwing with what is allowed? You are probably right in saying they have changed the formula. To meet EPA standards and lessen solvents the finishes will be drying more slowly.

I would recommend you contact Poloplaz and ask about Primero. You might also check out Floormasters on the web.

Using an oil based polyurethane over Zinsser finish

Q: We have 150 year old red oak floors with several coats of Zinsser Target clear epoxy based finish on them. We have been unable to find the same product and are thinking of using an oil based polyurethane over the existing finish.

Will it stick and not bubble or peel? What kind of prep is need prior to application?

A: I’m afraid I have no experience with this product. I would recommend contacting Zinsser.

You might perform a test spot in an inconspicuous place in the room. Rub the spot well with fine sand paper and apply a coat of finish and see what happens.

Can I buff the floors with a 220 and apply a semigloss coat over the satin?

Q: I have 3 coats of satin water based poly, over 1 coat of stain, on red oak floors. The satin finish is too flat. Can I buff the floors with a 220 and apply a semigloss coat over the satin?

A: 220 would be a good place to start. You don’t want to cut through the finish and remove patches of stain. 220 should be fine enough to be safe. Whether it will be coarse enough to buff the finish you are using I don’t know. Probably it will, but if not, then you would have to go with the next grit down which is 180.

Best finish for Cypress hard wood floors in home with dog and children

Q: I have Cypress hard wood floors and they are constantly getting scratches and dents due to the dog and children. I am having them refinished. What is the best finish to put on the floors to protect them? How many coats?

A: There is really only one solution to this problem. The dogs and children must go! Just kidding.

Any floor can be dented and any finish can and will get scratches. Some woods, even hard woods tend to reveal surface scratches more readily, such as maple. It’s very light natural colour and tight grain offer nothing in the character of the wood itself to hide these marks.

The harder the wood the more resistant it will be to denting and a floor finish itself will not alter this. Having said that, I include a short article from Poloplaz regarding finishing exotic woods. My usual approach is to apply 3 coats initially and another coat some time down the road to refresh the finish when it starts to get banged up.

Related Q: I am going to refinish my maple floors. I do have a dog. What would you recommend for a natural finish that will better withstand nail scratches? Could you also suggest the best how-to technique to accomplish this. I have never done this before, I have always had a professional refinish the floor, but money is tight so I am going to do myself.

A: I can’t give technique suggestions on sanding floors because this type of work requires a period of apprenticeship to become skilled. I use Poloplaz Primero which is a very tough finish. The problem with maple is while it is a harder wood generally, compared to oak, the grain is so thin, like pencil lines that there is nothing to hide nail impressions a heavy pet would leave in the floor.

Wet stain on unfinished floor

Q: We are in the middle of installing hickory hardwood floors. I’ve been covering up what he has laid with towels and sheets to somewhat protect it, but we have found a stain of some sort upon picking up the towels.

I suspect it is either dog urine, or a spot where a big wet dog laid down and some of it went through the towel onto the unfinished floor.

I’m afraid to do anything for fear of making it worse. Will sanding it take it out? Is there a product and technique I can use to remove it? Thank You.

A: Yes, sanding should be able to remove this. It is very likely just a surface stain.

Poly repelled from seams of sanded wood floor

Q: I just sanded some old floors that I installed about 20 years ago. I sanded them with 40 grit, 60 grit, 80 grit, then buffed it with 100 grit screen. Then I put golden oak stain from Minwax. After the second coat of Lenmar oil poly, I went to put third coat on and I noticed all through the house at the seams and the butt joints the poly looks dry and the middle of the board is shiny. It looks like I missed polying the seams. What could have caused this? I have picture if you would like me to text them to you.

A: Sounds like a contaminant. Were these floors waxed by chance? Because it can get into gaps between the boards and the solvent in the polyurethane causes it to bleed out and repel the polyurethane.

Q: We moved into a 50 year old house. Before moving our furniture in, I sanded the floors, applied several coats of Minwax oil-based stain, and applied three coats of Minwax polyurethane, also oil-based. Five months later, the polyurethane appears to be separating from the wood at the cracks between the planks in high-traffic areas and in some places the separation creeps toward the middle of the planks. The floor boards do move somewhat, but aren’t particularly unstable.

Is it common for the movement of boards when being walk on to cause this separation of the finish? Should the finish bond strongly enough to the wood to tolerate this? Maybe some contaminate is to blame? Is there any way to fix the problem spots so the bare wood isn’t exposed?

A: If the finish is peeling in the center of the board, you probably didn’t buff/scratch the previous coating enough to gain a good bond.

To fix it you will have to buff the finish down to the finish film that isn’t peeling. This will be tricky to do without removing the stain too. If it is just a couple of boards, maybe you can tape them off and just do those boards over.

Follow-up Q: The peeling doesn’t begin at the center of the board, it begins between boards where there is slight movement when the boards shrink in the winter. Only on some of the boards it spread from the cracks into the center of the board. Are you saying it’s common to see this issue at the cracks but if it spreads to the center it’s indicative of poor bonding? How can I tell if it’s just a layer of the poly peeling up or if its actually exposing bare wood?

Sorry for the persisting questions.

A: I wouldn’t say it is common to crack and peel at the edges. This could happen if there is serious shrinkage. The finish will only stretch so much and then it will fracture. But it won’t peel off the board unless there is a bonding issue.