Light (UV?) areas appeared on floor after applying poly

Q: I have just resanded and finished my 15-20 year old red oak floor. We stained it a week before putting on a water based poly, and it looked great before we applied the poly.

Once we applied the poly finish, light areas appeared on the floor. They appeared where the light has come in from the sliding door and windows. Can UV cause the floor to lighten within the week before applying the poly finish? We left the blinds open, but there was only a day or 2 of sunlight during this time. Or is this just a result of years of UV light damage?

I’m not sure I can live with it the way it is, so what are my options? Resand/restain a lighter colour?

A: When the floor was sanded to clean wood did you notice a shading difference?

If you can’t live with what you have the only chance to change it is sand again. I would use a stain which I know dries reliably and quickly such as Dura Seal Quick Coat. if it is a darker colour, water pop the wood first. This means wetting the floor surface to open the grain, allowing better stain penetration. Then start applying finish coats the next day.

Spot treating a dent in floor

Q: We recently had our floors sanded and refinished. We used a Bona satin finish (the one with the hardener). It looked really nice and then a coffee cup with metal left a large crescent shaped dent in 2 boards. My husband has attempted to fix the affected 2 boards by sanding, restraining and applying the topcoat with a stain brush.

He is on the 3rd coat and it’s really highlighted. It does not look the same thickness at all. Is there any suggestion you can give us with spot treating?

A: The finished used was Traffic? Make sure it is well stirred first. Thin coats are generally better and recommended than thick for curing reasons. Water borne coatings also are not generally considered high build either. That is one way of saying the urethane solids content in the finish is less than an oil/solvent based coating. I would put blue painters tape around the area to be coated. Do the entire boards affected. Lightly sand as needed (an abrasive pad works well for this. Don’t use steel wool). Coat the area enclosed by the tape and then remove the tape before it dries. There is no guarantee you can get an invisible patch with top coats but water based finishes are generally a bit more friendly in that regard than oil based.

Stain appears to have been applied over polyurethane

Q: My daughter bought a house with stain that appears to have been put over the polyurethane several years ago. The stain is now scratched and looks horrible. Any advice on how to remove this stain?

A: This floor needs to be sanded to clean wood and done over. Applying a stain on top of a surface coating such as polyurethane is not going to work. Stain is meant to penetrate into the wood surface with finish on top of it.

Water and snow has damaged finish by front door

Q: My floor is beautiful. It’s approx. 10 years old. My problem is in front of my entrance door.

Entering directly from outside and stepping onto the floor with water and snow has damaged the finish. I have some pitting and deep, dark spots in front of the door.

What is best, least expensive way to fix this 2′ x 2′ area?

A: If the dark areas indicate bare, exposed and now discoloured wood because the finish has so degraded, then the area may have to be sanded to bare wood and finished over.

If you can tape off and restrict this sanding to precisely the boards affected the end result will look less like a patch, though you may have to finally buff and re-coat the entire room to get a better blend.

Can water popping cause cupping?

Q: Can water popping cause cupping? Out Southern pine floors were installed and sanded. Then they water popped the floor to apply stain, which ended up looking very good. Sadly the floors looked cupped almost right after the finish was done. Since the process between the installation and finish was so quick, I’m not sure if my cupping is caused by the humidity in the house/crawling or if there was something wrong with the staining process.

A: I water pop hardwood often, especially when working with darker colours. I never do so with soft woods simply because it can take much longer to dry and because the wood is soft, I don’t feel I need to water pop soft woods to achieve the desired colour.

Having said that, I don’t believe there is much chance water popping could cup your floor. Water popping is simply wiping the surface of the floor with a wet cloth to make sure all the surface is wet, not soaked. How did they wet the floor?

Are there a lot of significant gaps between boards? I ask this because cupping occurs when there is an imbalance of excessive moisture coming up from the bottom of the board. Crowning (the middle of the board is raised higher than the edges) occurs when it is the surface of the floor which has received excess moisture. So, unless they really soaked the floor and water was able to seep between boards to the sub floor I don’t see water popping being an issue.

Likewise, and again depending on gaps between the boards, if they used a water born finish and applied several coats on the same day I could see that potentially causing a problem. It seems unusual for pine to cup. I’m not sure I’ve ever seen it happen. But it is not unusual for it to suffer significant shrinkage after being installed.

What is beneath this floor? If it is a crawl space that is damp, wet or humid that would be my first suspect.

A couple of additional questions. Was this pine left in the house for a time, say a week or two before being installed? Do you know if they happened to check the flooring and the sub floor with a moisture meter before installing? Do you live near a significant body of water, say the ocean for example? In such cases acclimation of wood to the environment takes on even greater importance.

Follow-up Q: Thanks for your answer. There are pretty much no gaps in between boards, all boards look pretty tight together. Was there supposed to be a gap between boards at installation? if so, how much? I saw the water popping process and they didn’t use much water so now I’m thinking the installation was done incorrectly or my crawling space is too humid.

To answer your other questions. I don’t live near the ocean or lake. The floors were in the house for a couple of weeks before installing. They didn’t not check the humidity of the floors and crawling as far as I know.

Here are a couple more details to narrow it down: The floors were installed in North Carolina in December and the house was vacant at the time with construction going on so the heat wasn’t running very high during the process. Maybe between 55 to 65 degrees. My crawl space doesn’t feel particularly humid. What is the ideal humidity for the crawling space and floors to be back to normal state? Once again thank you for your time.

A: Some gapping would be expected as normal. Great if you have little to none. This is not caused by water popping. I would focus on the crawl space. Have you had the installer come back to check these things out?

Water damage from flower pots

Q: We had a flower pot in the dinning room, on a rug over our hard wood floor. When I picked the rug up I discovered some of the floor has darkened.

A: Sounds like this has happened over a long period of time to cause water damage like this. You will likely have to replace the damaged boards to make this spot go away.

Related Q: I recently over-watered a plant in our living room and it overflowed onto our hardwood floor. Before I noticed it, I happened to go into our garage (which is directly under the living room) and found that the water was pouring out from the underside of the floor. Should water just flow straight through so easily?

A: One would not think so but clearly the water found a way between the boards of your hardwood floor (that means you have pre finished or some significant gaps between boards) and then found another gap in the sub floor; whether your floor is sitting on plywood or is a much older house with pine or spruce plank sub floor.

Similar Q: Can spilling a glass of water on a hardwood floor, yet wiping it up within 5 minutes, cause the floor to crack?

A: I don’t know what you mean by crack, and I assume this floor has some sort of finish on it. I would consider this event insignificant.

Wax to stop the creaking sound?

Q: What can I do to stop the creaking sound my wooden floor makes when you step on it? I heard that you should wax the floor.

A: You shouldn’t wax a floor if it is finished with a polyurethane or similar top coat. Waxing won’t stop the creaking in any case.

The movement in the floor is very likely also related to a loose and moving sub floor. The only sure way to remedy this is to replace the floor. Nail down the old subfloor with spiral nails and if need be, screw at least 3/8 spruce sheeting over top, then a new hardwood floor.

Related Q: We installed hardwood floors in our house 2 years ago. We used all short boards. It looks great, but the whole floor pops as we walk across it. I thought that maybe it was because we have so many joints, having used the short boards, but we have no idea how to fix it.

We put a new layer of OSB down since taking out the old floor left the original subfloor weak. Do you have any suggestions on how to fix the popping?

A: If the problem is the OSB no holding the nails, there isn’t much you can do short of removing the floor, installing plywood and then installing the floor again. Perhaps you can fire the occasional 2″ nail from a trim gun and putty the hole, but I’m not very hopeful that will work.

Vacuum cleaner blade got hot and melted the finish

Q: I have dark Brazilian Cherry wood floors. It appears, in a few places, that the vacuum cleaner blade got hot and melted off the finish of the floor. It’s a line about 8 inches long and 1 inch wide. My floor is a matte finish, but where these lines are it’s now shiny. Any suggestions?

A: First, try wiping it down with some polyurethane cleaner or perhaps mineral spirits. If the mark is still there you should be able to remove the sheen by rubbing the spot with 000 steel wool.

Dark round pigmented areas

Q: I have sanded my old pine floor boards and finished with water based lacquer. Around the floor nails I am noticing dark round pigmented areas. Is this normal with reclaimed floors or is it because I used water based lacquer? I think maybe this is oxidation from the nail?

A: It sounds like a reaction of your finish with tannins in the wood. There are water based sealers designed to block such.

Gradually stain area until I can get it to match?

Q: We stripped and sanded our pine floors in our 100+ yr. old cottage.

Long ago, the previous owners painted around the large throw rug in middle of room. Eventually it sat for decades under wall to wall carpeting.

I was able to get three sides to blend with center but 4th side is much lighter than middle section of the floor. Do I try to sand this line / area to blend both areas or is it best to try to gradually stain until I can get it to match?

A: I would accept that this is the colour of those particular old boards and stain as normal. Old pine will offer a range of colouration and this is a natural part of aging.

When I nail down one board, another pops up

Q: I’m trying to refinish the hardwood floors in my house. My house is from the 70’s, and this is the original flooring. When I nail down boards other boards pop up a little, making a bigger gap in other boards. It doesn’t level out. It’s wavy.

A: I’m not sure what your question is but it sounds like your floors have been subject to higher than recommended moisture levels over time. It also sounds like they may not have been nailed down well, or were installed over a poor sub floor material such as Aspenite.

Nothing much you can do to change that short of removing the floor, fixing the sub floor and installing a new floor. I would encourage you to hire a professional for sanding and finishing. I’ve seen many such floors virtually ruined by a home owner trying to save money by doing the work themselves with rental machines. For the time, expense and potential ruin of the floor, it isn’t worth it in the end.

Staggering wood floors in where walls were removed

Q: I am thinking about taking down some walls in the living room, which has beautiful hardwood flooring. Can the gaps on the floor (where the walls used to be) simply be filled in with more hardwood, and entire floor then sanded down and stained to match?

A: Yes, of course you can install flooring to match where the walls have been removed, provided the existing flooring has a thick enough wear surface to tolerate a complete sanding. To have a less noticeable patch every row of boards will have to be individually cut back and staggered, then new pieces fitted in.

Sometimes the installer originally may have had to change direction when dealing with these walls. If that happens so that the tongue is facing opposite directions on each side of the repair, you may have to simply cut one side straight but stagger the opposing side.

Similar Q: I recently took out the carpet covering my hardwood floors. There was a wall previously removed and there is a gap between the floor boards. Is there a way to fill the void?

A: Stagger the boards on both sides of the void and put in new hardwood.

Gaps in glued down floor in high humidity climate

Q: I am buying a house that has old hardwood floors that look great. There is an addition that is newer and the hardwood is installed on a concrete slab. There are some gaps between the boards (the short sides), some as big as about 1/2 inch. The boards are not nailed down due to the concrete. The seller had a guy come out and look at it and he wouldn’t put putty in because he said it would look awful.

Any suggestions? We thought of taking off the shoe molding and trying to slide the boards in the right direction. Would that work? We’re deep in the south with major humidity all the time.

A: Installed on a concrete slab, it has to be glue down. Trying to move the floor out of the position it is in could break the glue bond, and where will that leave you?

I think you need to try to control the environment in the home as best you can. Keep the RH 45-55%.

Warped stair treads after fire

Q: I recently had a fire in my home and the stair treads are warped from water damage. How can I fix them?

A: That depends how warped they are. If it isn’t severe they can likely be sanded flat but you have to make sure they are dry first. Otherwise, you would have to have the treads replaced or the stairway refaced.

Glaze applied to floor causing cupping?

Q: I had my 75 year old hardwood oak floors re-glazed with —– by a company about a year or so ago. They are cupping pretty badly. Since there are rooms that weren’t refinished by them that aren’t cupping, I assume the company created the problem. I’m thinking they were sealed so much on top that they can’t breath any more so what humidity they get from below is not vaporizing as it once did. Is there a way to “strip” the water based poly glaze they used in order to let the floor breath again and possibly flatten out?

A: You will have to have the floors sanded to clean wood. You could likely remove the coating with stripper which would be an awful and time consuming job. And you would still have to sand them anyway. I’m not familiar with the product you mentioned. Is this some miracle do it yourself product sold at a big box store?

Rug outline on newly finished floor in short time

Q: I had my wood floors refinished 2 months ago. I waited 3 weeks to put furniture and rugs down on them. I was vacuuming last week and rolled back the rug to vac underneath and found that there is an outline of the rug on the refinished floor. I don’t have a skylight or large windows, and it’s only been a few weeks since the floors were done. My floor guy has no idea why this has happened. The floors never had the original finish done over 30 years ago. Help please!

A: It would have been great if you posed an easy question. This is strange and not usual for native north American species of wood. Some of the more exotic imported woods such as Jatoba can change this rapidly. You allowed plenty of time before putting everything in place. Exactly what kind of finish was applied? Solvent or water based? Is there an under pad with this area rug?

Medallion is coming up around the edges

Q: We hired a flooring contractor to do our floor which included a feature strip and a compass rose medallion for the center of the floor. Cut to the chase, his references must have all been friends or family because he knew nothing about the process. Now the medallion is coming up around the edges. The medallion has a fiberglass backing, and I am wondering whether with extreme care and lots of time, it just might be possible for me to pry it out of the recess. Any suggestions?

A: I’ve worked with feature strips but never had occasion to install a medallion. If adhesive was used I doubt you will get it out in one piece. I think I would contact the company who made the medallion and get their advice. There is a forum I used to participate on years ago that might be helpful. I knew a guy on there who made medallions. You can do a search and see if you can find an answer.

I am curious as to why the medallion is now lifting. Did he not use enough adhesive or is the adhesive failing? Is the floor under some pressure from moisture imbalance? I’m thinking it is likely poor fastening.

Follow-up Q: The really sad thing is, we had a medallion installed in another house, so we kind of knew some of how it should be done. We supplied the installer with the adhesive brand and type recommended by the maker of the medallion. We told him that the medallion was to be finished at the same time as the floor (sanding etc.). We gave him YouTube sites to watch. We asked if he had ever done any medallion installations and the answer was, “yes.” He apparently, just went about it in his own way.

A few days after the job was done and we could walk on the floor, we noticed that it appeared that glue was oozing out from one area between the edge of the medallion and where the floor was cut out. We put some weight on it and let it set a few days hoping the glue would set up. It never did. We had him come back and look at it and he agreed that yes, the glue was oozing out and the edge of the medallion was lifting. His response was, “What do you want me to do about it?” We told him that he was the professional, that was why we hired him. What do you think should be done?” He said he would nail it down. At that point, rather than have him even try to fix it, we figured the best course was to keep him away from it and from us.

Since that time, it has only gotten worse and glue is now oozing out on the opposite side and the medallion is lifting there too. We are going to contact the maker of the medallion for his take on it. It is very disheartening to investigate references just to find that this contractor, just didn’t know what he was doing and was unwilling to use the help that was provided him. I think he must have just used Liquid Nails or a similar product not appropriate for the application. Thanks for the very timely response.

A: Boy, this is a shame. Can you tell me what adhesive you recommended to him? And you don’t think he used what you recommended? Honestly, I’ve never heard of an adhesive not setting up and drying. Clearly what he used is still active. Maybe I can learn something here too. My guess is, and I likely would have used some type of polyurethane adhesive or Dri-tac. There is a recommendation with at least some polyurethane adhesives to allow 20 minutes or so for it to skim over. A ‘wet lay’ can be used too but you risk having adhesive squirt up the edge of the board. But I’ve never heard of adhesive not drying.