Do hardwood floors always buckle if there is a leak underneath?

Q: I have dark stains on my hardwood floor that I am noticing 3 years after a remodel. I suspect a leak, but the floor isn’t buckling. Do hardwood floors always buckle if there is a leak underneath?

A: A buckled floor would require a flood.

However, excess moisture often does cause some cupping with the board edges raising higher than the center when the water imbalance is from beneath.

Blue dye stains in hardwood

Q: I had a new red oak floor put down. At each board end, where the boards meet, there is a dark color developing, almost as if the oak were wet. What causes this, and should I worry about it occurring once the poly is down? Is this tannin?

A: It’s possible this is caused by microscopic fungal spores. You could do a search for blue dye stains in hardwood. I don’t think there is any way to get rid of it now that it left the drying kiln.

Somebody may also want to put a moisture meter on those areas to make sure it’s moisture is within specifications, 7-9%.

Sump pump flooded laminate floor

Q: My sump pump failed and flooded my in-progress reno. The laminate floor has bubbled in about 25% of the floor. I will replace the floor eventually, but I’m really not up for doing it now. The water was on the floor for about 5 hours.

I vacuumed it up and sucked it out. I have my heated floors on. Will the heated floors dry it out from underneath? I have heaters in the room and a dehumidifier on which has brought the air moisture from 46% to 30%. Is it a health hazard to leave it? Will the in-floor heating dry it out?

A: The thing with water is it doesn’t just disappear if we turn up the heat. I would pull it all up because if the water cannot escape into the air it will be a great environment for mold development, especially with the increased heat. Mold loves warm and wet.

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.

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.

Damp mopping causing dark spots?

Q: I have customer — we clean their house every week. Part of our process is to damp mop the hardwood floors throughout the home. We use a mild peroxide based cleaner that is diluted according to manufacturers directions for the damp mop (EcoLab). Recently three dark spots appeared on the floors, blackish and about 12 inches in diameter. one has a sharp side about two inches running parallel to the carpet. The owner thinks we left too much water on the floors and it caused these spots. I sent pics to a local hardwood floor company and they said it looked like dog pee — I ordered a blacklight. The owner is sure their dog didn’t do this and that we put too much water on the floor. The owner said he talked to friends who work in the flooring business and they are certain that it was caused by water damage. BTW it has also been raining here off and on for a month in NC. If the black light shows markings then I will discuss the uric acid issue – but if not, what should be my next step to assess this?

A: Is there a basement under this room or just a crawl space? For your own benefit I would suggest using a floor cleaner manufactured by either wood floor manufacturers or floor finish manufacturers. You can spray mist a section of the floor and then wipe over it with a dry cloth or micro weave or terry cloth mop. This cleaners evaporate quickly. Companies that make such cleaners include Poloplaz, Basic Coatings and Bona Kemi. Leaving any amount of liquid on a wood surface long enough is bound to create a water stain. My guess, given the marks as you describe, sure sounds like pet stains. I’m not sure what to suggest. A pet who normally never goes in the house can suddenly change for several reasons, two of which would be health issues and emotional upset. Have you ever noticed wet areas when first entering this home because this sounds like it has been repeated more than once in the same spot.

Follow-up Q: I haven’t noticed wet areas. There is a basement under the house although I’m not sure if it spans under the affected areas. We have cleaned this house 3 times and we use microfiber cloths that have been rung out. Even if the were not fully rung out it is hard for me to envision that they would leave enough water behind. The pet is in the house but the owner says there was never a problem before. We also have had more rain in the last month than I recall. I Will send you some pics of the spots. Thank you for responding.

A: Why these significant black spots in a few spots, because it seems to indicate standing moisture of significant amount..

Follow-up Q: The other question I guess I have is if I want to get an unbiased expert opinion on this , someone I could pay to come out. Would a building inspector be the right person? Or someone from a flooring company? It seems that in order to fix a spot you need to know what the root cause is. Where would one go to get someone who would take an educated scientific approach to figuring this out?

A: Contact the National Wood Flooring Association. They do have certified inspectors. If you go this route, I’d be interested to know what his conclusions are. Thanks.

Dark spots under finish that look like blood splatter

Q: I have a house that was built in 1910 in Crescent City, FL that has heart pine floors throughout. These floors were professionally finished about 9 years ago with I believe a poly finish. I am only there once a week but noticed numerous dark spots on a small area of the floor that looked like blood spatter, that is the easiest way to describe it. When I tried to clean it up I realized it was under the finish, and if I try to scrape the area it turns slightly gray. The house sits off the ground about 12″ on a concrete wall with a sub-floor under the heart pine with a sandy soil as the base. What could cause spots like this to appear after over 100 years? There is nothing under this area that could heat it up and no water damage. I am wondering how I am going to spot strip the area and match the finish. Have you heard of anything like this before? Thanks for your help.

A: That it turns gray when you scrape it indicates to me it is a moisture stain. Perhaps some mold forming from excess moisture coming from beneath the floor? That’s my best guess.

Related Q: Our laminated flooring, on a slab house, is turning dark. Is this mold? Could it be the wrong glue was used?

A: I would wonder if there is enough moisture to create an environment for mold. Why aren’t there other obvious signs of water issues such as curled edges? I would contact the manufacturer of the flooring.

Related Q: I have found an apartment that I really want to move into. However, there are strange stains in the corners of some of the rooms and hallways. I am afraid this is mold and could be hazardous to my health. However, most people in my life have told me they are simply water or pet stains.

A: They probably are pet stains. Mold requires a warm, damp environment to grow and survive.

Replace over 100 cracked boards or replace whole floor?

Q: In our new home (we have had it for 3 months) the maple floorboards are cracking. Our builder wants to lift and replace only the cracked boards. However, at this stage there are over 100 boards that need replacing, and more are cracking as time goes on. We have installed a dehumidifier in the home as the builder thinks it’s due to too much humidity because we had cupping as well.

My question is, once so many boards are lifted and replaced by gluing in, will they lift and become uneven over time? Will my floors look level in say 4 or 5 years? I have heard that the glued floorboards will eventually not be level and I think the builder should be replacing the entire floor.

A: I will make an assumption that your maple floor is pre-finished and has bevelled edges. You may be surprised to know the reason they have the bevels (eased edges) is because these floors are NOT perfectly flat. The edges help to hide that. If he uses a polyurethane adhesive I would not expect the boards to move or come loose.

I would certainly be concerned about the cupping of the floor. It is definitely connected with excess moisture coming from below the floor. I doubt this is caused just by excess humidity. Has anyone placed a hygrometer on the floor to see what the RH is in the home? What about a moisture meter to take some readings of the wood itself? This is something that should be done before the floor is ever installed. Was the sub floor and the maple checked with a meter before installation began? It is a new house. At some point it was wide open with no roof, no windows, no heat and exposed to the elements. The plywood at some point had to be wet. Was it within 4% moisture content of the moisture in the maple when first installed?

The horse is out of the barn now. I don’t know the square footage of the entire floor area. Over 100 boards needing to be replaced seems like a lot. Sometimes it makes more sense to just start over, but apparently the builder doesn’t feel that is the case.

How are they going to deal with the cupping? The source of the moisture will need to be addressed first. If the basement is open, they may want to put a meter on the plywood to check it’s moisture content. If the floor now shrinks as the heating system comes on you may then be left with a lot of gaps.

Can Pepsi strip off polyuerthane finish?

Q: I put water based polyuerthane on our floor. It looked very good, but when some Pepsi got spilled on it, it striped off the polyuerthane finish. How do I fix this?

A: I’m at a loss as to why Pepsi would cause a floor finish to delaminate from the wood. I’m thinking you may not have abraded the previous coat sufficiently to gain a good bond. The moisture from the spill was able to get under the coating and lift it off the floor. You can try taping off the affected boards and rubbing them down really well with fine sandpaper and coating again. Then remove the tape.

Gaps from a puddle left on wood floor

Q: I poured water all over the floor to mop, and I left a huge puddle on the floor. I came back and dried it up and then noticed big gaps between the floor boards and the ends of the boards popping up. How do I get the floor back to normal?

A: Excessive amounts of water is an enemy of most woods. I would set up fans and a dehumidifier and try to dry this floor out. You will likely not be able to do anything but fill the gaps because the floor, under pressure from so much water has swelled, moved the boards. As it dries and shrinks it leaves gaps.

Similar Q: I had just broke my foot and I iced it then I put a plastic bag on. The hardwood of my bedroom I noticed it was wet when I got home from school and it was a little peeling to do you think this is a big problem? What about mold?

A: You don’t have any worries about mold but I imagine the affected boards may either crown or cut. The only thing you can do now is wait and allow time for it to completely dry out.

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.

Dog vomit caused bubble in finish

Q: I have a small bubble raised up in my floor caused by dog getting sick while I was asleep. What can I do to to flatten the bubble?

A: Is this a bubble in floor finish or do you have, for example and engineered floor and the top veneer has bubbled?

Follow-up Q: It is a bubble in the floor finish.

A: Strange. I’m guessing it is caused by stomach acid. Poor dog. You could try a small wooden or otherwise roller but you might have to pick this spot off and apply one or more thin coats of finish.

[Sort of] Related Q: How does one remove dried cat vomit (it’s set up like cement) from hardwood floors? I don’t want to use anything that will scratch or mar the floor or its finish. I hope you can help me.

A: I would think to wet it (the vomit itself) maybe with a mix of vinegar and water to soften it.

Related Q: Can dog urine make an oil base polyutherane varnish bubble up? What about Coca Cola?

A: No, I would not expect urine or coke to cause polyurethane to bubble up. Paint stripper would.

Mopping left gray water stains in unfinished spots

Q: We had an assistant to our cleaning lady mop our hardwood floor two or three times before we found out what was going on- we of course immediately told them to stop.

The finish in a few small spots has come off and there are a few spots that look gray. The spots are small (dime sized and smaller) and they are all within a 3’x 3′ area. What can we do to fix this?

A: Sounds like the finish has come off the floor and left the wood water stained. You will have to sand those stains off to clean wood and apply a thin coat of polyurethane to just the spots.

When dry, lightly buff or abrade the entire boards affected with fine sand paper and coat the entire board. It helps to apply painters tape around the affected boards before coating, but remove it as soon as you have finished brushing on the finish.

Pine floors curling after refrigerator water line leak

Q: I had a refrigerator water line start leaking under my 60 yr. old home. The pine floors started curling and this affected parts of two rooms before I noticed and repaired the leak.

What steps should I take to dry the floor back out? I have heard that some of the curling issues may go away after the floor dries back out. It’s 90+ degree heat during the day and low 70s at night here, just starting into summer.

A: What do you mean by leaking under your home? Into a crawl space? The idea is to remove the excess moisture from beneath the floor, the sub floor and the finished floor.

Fans and dehumidifiers will be very helpful. Yes, often a floor will flatten out on it’s own. Let’s hope so.

Related Q: I have a 3″ x 10″ spot on my hardwood floor that rippled a little bit after I discovered that water had spilled and set on the floor too long. The floor is 10 years old and still in excellent shape, except this spot that was just rippled. Can I steam it and try to press it flat again? what do you suggest?

A: I definitely would not steam it. You could blow a fan on it for a number of days, but this is going to be a waiting game.

I have seen floors do this and then flatten on their own. Sometimes they don’t. I would give it several weeks to find out.

It is also a good idea to have a dehumidifier running, especially in the basement if it tends to be a bit damp as many basements are.

Black residue in cracks after spill

Q: Just noticed that a black substance (could it be mold) has filled the cracks between the pre-finished floor boards in a small area (about 2 foot by 3 foot) of my bedroom hardwood floor. There was a spill of a DampRid Moisture Remover container in that area just a few months ago. I’ve removed some of it using sewing needles to scrape it off, but much more remains. Any suggestions on how to deal with this?

A: Perhaps a bit of bleach on a cloth, using a dull knife to get the cloth down as far into the tiny groove possible. It’s one of the draw backs of this type of floor. Spills are more likely to find their way under the floor and can take a while to completely dry. This doesn’t mean you now have a mold problem. Mold has to have the right environment to continue.

Similar Q: I have noticed some quite large black patches/marks on the wooden floor in our bedroom, which must have developed very recently. It looks almost like burn marks and even the wooden baseboard has a dark marks, almost as if someone used a blowtorch on it. My partner has made a (bad) habit of leaving his dirty clothes in that particular spot which sometimes consists of damp gym clothes, could this be the what has caused those black marks? We have underfloor heating so I suspect this may also be a factor.

A: Damp clothing left sitting on a warm floor sounds like a good breeding ground for mold. Unless there is a small leak nearby, that is likely the cause.

Hump in kitchen floor from basement flooding below?

Q: Our basement flooded in Sept. It was right under our kitchen floor. We have noticed the kitchen floor now has a big hump in it. Could it be related to the basement flooding? The adjuster does not seem to feel it was related to the flood. What do you thank?

A: I think it is certainly possible, if you had a significant amount of water in the basement, below the hardwood in the kitchen that it could impact the wood floor. Did anyone take moisture readings of the kitchen sub floor from the basement? What was the cause of the flood? Your floor has a hump because it has expanded and is under pressure. This is only caused by moisture imbalance. What is the source of the moisture? Unless you have a leak from your refrigerator or dish washer, the other likely source would be the water in the basement.

Follow-up Q: They did take moisture readings in the kitchen and it read normal levels. The flood was caused by a sump pump malfunction caused by a power failure. It was a whole week before servpro set up dehumidifiers, which ran for 3 days. So the basement was flooded for several days. They said there was no leak in the fridge or the dishwasher. Our floors are a vinyl tile which are now starting to pop apart because of the hump. I appreciate your info. Please let me know what else you think.

A: Having a large volume of water sit in your house will impact other parts of the structure. As it evaporates it has to go somewhere. If the sub floor is plywood, it is likely it has swelled. This is why even plywood is suppose to have a small expansion space between sheets. How do they explain the hump? I think you are going to have to remove your tile and fix the floor underneath first.

70% of our floor, installed over concrete, is cupping

Q: I had a very expensive hardwood floor installed on concrete about a year ago. It started cupping in places within a month, and now the problem has spread to about 70% of the floor. I have had both the manufacturer as well as the company who installed the floor originally back to inspect the problem. Nobody can give me a satisfactory reason why they should not replace the floor. Can you suggest a reason why “it just happened” and they should not be expected to fix the issue?

Is there a product they should have used to seal the floor, if in fact “the concrete is bleeding moisture”? Should they have tested the moisture level of the concrete to check for the need of said products use? This is not a fly by night business, so I trusted my purchase would be installed correctly and the manufacturer would honor a warranty for a faulty product. Please if you have any information or suggestions, I would appreciate any help!

A: If this floor is below grade there probably isn’t a solid wood manufacturer who would warranty it.

In any case, if installing on concrete even a slab at ground level the slab should have been checked first for moisture penetration. If I faced such a floor “bleeding moisture” I’m not installing the floor directly on the concrete. Clearly you have a moisture issue.

There are a number of adhesive type spreads available which serve the purpose of both a sound retardant and moisture barrier. Bostik makes such a product.

In your case it sounds like you may have been much safer putting down some type of membrane over the concrete then using dry core, for example, and installing an engineered floor on top of that.

If you have moisture coming through the concrete it is only a matter of time before mold also becomes an issue.

Will ridges flatten if we place weight on them and ventilate?

Q: We installed prefinished hardwood in a bedroom 1 1/2 years ago. The tenants ducted the dryer exhaust from the laundry across the subfloor and joists below, and never checked the vent, which became plugged with lint. We now have a section of floor which the 3/4 inch thick X 2.75 inch wide boards have swollen and bulged upwards, forming ridges.

Will these ridges settle if we place weight upon them and ventilate the area below? We have spare replacement lengths to repair the whole area, but prefer to delay that if possible.

A: Ventilating is a good idea. I have seen such floors flatten. Give it a month or 2 and see if it does.

Water damage to my solid hardwood floors when a pipe broke

Q: I had water damage to my solid hardwood floors when a pipe broke. My floors are parquet and probably 50 years old. They buckled. I brought in a dehumidifier and the floor actually dried out and is now flat down. Now, they are still cupped and there are some gaps in the floor.

I can’t decide if I need to replace the floor or if the damage could be fixed by refinishing. I’d appreciate your thoughts. Thanks!

A: The structural stability of the floor has likely been compromised. A water soluble adhesive was likely used when installed. When the flood occurred the adhesive softened and the floor buckled. It has gone flat since, but how well has it bonded to the adhesive? I would suspect the entire floor or large parts of it are now or will become loose.

I would probably consider the floor lost. Somebody is going to have to sand it to get it really flat again and all these pieces/slats are going to start popping loose.

Follow-up Q: Thanks for your reply! The floor was put down in the 1950’s using a black, tar like adhesive. The adhesive appears to have come loose in the part of the floor most affected.

The problem is, only about 20% of the floor was affected and the rest is still in pretty good shape. They don’t make the floor anymore so I guess I am looking at total replacement. I hate the thought of all that good wood going in the landfill!

A: Is this parquet block? Tongue and groove, possibly 3/4 thick? Have your floor guy put his moisture meter on the floor. If it is stable, it can be sanded over. If these are blocks and some are damaged you may be able to make your own from 2 1/4 wide strip.

Related Q: I have tongue and groove, soft pine flooring. I had a water leak on a section of the floor. The floor did get wet, and after using the shop vac to get the water up the floor starting drying and started producing a cracking sound. Now several of the floor boards have risen up along were they come together. What can I do to repair them, short of replacing them?

A: I would leave it for a month and see if it drops back down on it’s own. If not, it will have to be sanded flat.