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.

Cold causing wood floor to buckle?

Q: My hardwood floors have buckled in my 1928 mountain home, due to the heater being destroyed in the basement which flooded. How can I fix them?

A: So, from your description it sounds as if the moisture is rising up from the basement, going through the sub floor, the hardwood and out. I would get dehumidifiers running, one in the basement and one on the main level and then wait it out and see if the floor will flatten back down.

Follow-up Q: The basement has been dried out for a year. I haven’t replaced the Heat A.C. unit. It’s the COLD that’s making them buckle. I don’t know how to get them to flatten out again.

A: I don’t think it is the cold that is causing your floors to buckle. Only moisture in excess can do that. I would buy a couple of hygrometers that show temperature and relative humidity. Place one in the basement and one where the floor is buckling. If you could get your hands on a moisture meter you could also test the sub floor from the basement and the floors upstairs to see what type of reading you get.

When you have a better idea what type of moisture levels you are dealing with you can decide if a dehumidifier or 2 may help. I think if you can get the floors down to acceptable limits it may flatten on it’s own. It might also help if you can remove the quarter round on the side walls to see if the floor is installed tight against the baseboard or outer walls. If it is, the floor has no room to expand. If you could cut 1/2″ off which would be hidden under the trim anyway, that would help relieve the pressure.

Related Q: This house is less than a year old. At first when my partner and I moved into this new house everything seem to be fine. A couple months later, we noticed that the hallway timber floor was starting to lift. Eventually the floor lifted quite high and some parts of the timber are starting to split. Any idea what would cause this problem?

A: There is definitely a moisture issue at play here, whether it be a leak from the bathroom or laundry room. The floor is buckling because the boards are growing due to increased moisture content. It will take some investigative work to isolate exactly where the excess moisture or water is coming from.

Similar Q: I am in a condo and the tenant above had a flood a year ago. A team came into my condo to see if there was moisture under these very expensive wood floors, and there was. Some kind of air sampling was done. They brought in 2 fans and had them going 36 hours (there was no water to “see”). Now, more than a year later, the floors are buckling. Just where they had put the fans. If I replace only some of the floor it will look goofy. Also, since so much time has lapsed do you think the upstairs tenant’s insurance will cover it?

A: I honestly don’t know but it is worth a try, as it seems apparent the problem with your floor is connected to the water from your upstairs neighbour. Do you have some type of report from when the people came in to check for moisture, affirming that their was some?

Floors buckling; where could the excess moisture be coming from

Q: Six years ago I had a wood floor installed in my 2nd story. I now have floors buckling. The buckled floors are on different planes in each room. After the floors started buckling, we had over 10 inches of rain. This did not cause additional buckling so I do not think it is a roof problem. Any suggestions?

A: Well, there is nothing above the floors on the second level but the roof. Likely suspects: the roof, either toilet, sink or tub/shower on the second level or a second floor laundry room. It sounds like we are talking about a significant leak, not just a localized trickle. Anything happening on the main floor? Stains in the first floor ceiling?

Follow-up: No stains on the first floor.

Similar Q: We have a rental house in Corpus Christi, TX that is 85 years old, pier and beam and with oak? floors. We recently had the house re-roofed, put on vinyl siding and new windows (Feb/March). In August our tenant informed us that the wood floors were buckling up to 6 inches in some areas. This has never happened in the 16 years that we have owned the house. Our siding guy says the house is properly vented and he fixed a long-standing leak from the bathroom that was draining under the house. The tenant runs the AC at about 70 degrees. There is no dehumidifier. 3 Flooring guys have come through and nobody has figured out the problem or offered a solution except to re-finish the floor with a more permeable/porous coat and then to fix the damaged wood with no guarantees. We are trying to take care of this from a distance and don’t know what to do. Any thoughts?

A: Clearly this is caused by excess moisture coming from beneath the floor. You say there was a previous leak which was draining into the crawl space beneath the building. My thinking is that is the likely source of the problem. If it is just dirt under there you may want to consider laying down a tarp, plastic or some other membrane that resists moisture transfer. Did anyone check the moisture content of the wood flooring? Sanding is really out of the question until the pressure on the floor is relieved, meaning it has dried out to an acceptable range of 7-9% moisture content. You might also contact the National Wood Flooring Association to see if they have a certified inspector in your area who can come and give his assessment.

Follow-up Q: Thanks so much for getting back to me. There is no inspector in the area (I checked the website). We plan to relieve the pressure (short term floor fix) and try to increase the venting underneath the house and then fix the floor once the moisture contents are lower. There is just dirt (it is a crawlspace) under the house. Our flooring guy suggested a fan and some other means to try to increase the venting under the house. We are also planning on looking at tarp/plastic under the house as well. I was just wondering if you thought that there was a possibility that the siding, roofing and window work created some sort of change in environment that would adversely affect the floors. Have you heard of that happening before? The house is likely a lot more insulated/air tight than it was before.

A: It seems logical to me that if the house itself is much more “air tight” it could contribute to problems if there is excess moisture and no means to control that moisture. The cottage I’m working in this week has concrete block foundation with a crawl space and dirt floor. It is built on a hill and there has been a lot of work ongoing to moisture getting in to that space. Two guys were down there today to lay a very heavy gauge plastic sheet on the dirt. He says they seal the edges with spray foam so no moisture can come through the plastic into the space. The oak floors above were slightly cupped but nothing near the situation you face.

Having a well insulated and sealed house is a good idea in terms of comfort and energy savings. But we still need air exchange or else the indoor air quality will drop. It’s out of my expertise, but I do believe there are air exchange systems for highly sealed homes. Adding house plants would likely help a lot in keeping the air clean. Won’t help with the moisture issue though.

Tile better re: leaking water?

Q: My new guest house had to have the floor entirely replaced three months after completion as it was badly cupped. My builder found a conduit that was cracked and leaking water into the house and covered all costs. Now the floor is entirely cupped again and he is willing to replace again but admits that he does not know what is causing it. He recommends that I go to tile this time. I want wood! But, even with tile, won’t the moisture that is causing the cupping harm the subfloor and foundation? What can I do?

A: When there is a moisture issue the problem needs to be corrected first. Part of this also means making sure the wood structure the floor is sitting on is also dry and stable. Did the builder test everything with a moisture meter before proceeding? If this water was soaking dirt in a crawl space, was this all dried and vented and a tarp placed over the damp ground to impede moisture? Has anyone put a moisture meter on your wood floor to check readings? Normal would be 7-9% in most cases. If you get readings 15% or higher, you will have problems. If you are in a cold climate as I am, you could go through a heating season and see how the floor reacts and whether it gets worse or better and when you get normal readings on all structures and the floor have it sanded and finished or stained accordingly. And if you have an ongoing moisture issue under the sub floor I wouldn’t think this would be a good thing for the joists, etc. The moisture has to go some place.

Water standing on floors

Q: We live in Portland and we’re having some heavy rain. Unfortunately, when we came home yesterday we found water standing on our laminate floors in the finished basement area.

We’re not sure how long the water was there. It rained heavily all day and wasn’t noticed until we got home. We cleaned up all the water, and couldn’t find the source. Everything stayed dry over night and through the morning.

We had more heavy rain this afternoon and evening, so we now know our water source because we have more standing water. We’re having a new sump pump put in tonight which should resolve the problem.

I’m wondering what to do now? There are dark lines along the end-to-end seams of the floor. We obviously live in a wet and damp place, so I’m worried about mold. We’re not sure what’s under the floor. Do we need to find someone to come pull everything up? Run fans and let things dry out and wait for a certain amount of time? I’m more concerned about mold than the cost of replacing the floors because it’s a pretty small area (one bedroom and a hallway) that’s impacted.

A: Well sadly it’s probably best to remove at least some of it. It is likely a click together floor so this shouldn’t be difficult to do. Of course if you can’t match what you remove, then the entire floor would need to be removed. The odds are pretty high that it is wet under the floor and unless you expose the water or wet concrete it could take weeks to dry, and that sort of environment does feed mold growth.

Related Q: We had our sump pump fail in the basement where we have engineered hardwood floors that are glued together, floating over the underlayment. I have three dehumidifiers running, three fans, and the furnace on at 72* with all vents open in the basement. The floors aren’t buckling, but I’m wondering if the underlayment will dry out? Or start to mold under the wood?

A: I’m surprised you haven’t seen any negative reaction with the floor. It will dry out eventually and it’s normal for some air borne moisture to migrate through wood products. The idea is to have this happen slowly. So, yes it will eventually dry out. Will there be mold under the floor? There might be some. But mold requires a warm and moist environment to grow so unless you expect to make this a habit, at this point I wouldn’t worry to much about it. I’m more interested to see if you lose the floor or not.

Mold worries after leaky toilet

Q: I had a master bedroom toilet leak and it caused a lot of damage to the carpets, door jams, baseboards, etc. It also got under my expensive, hand scraped hickory (4 years old) installed engineered wood floors. They are glued down on a concrete slab. The water damage experts said that there was still moisture under wood floors in the hallway and part of the living room. The floors show no signs of buckling or color distortion. My contractor said the installer did a great job installing them.

I am concerned about mold. Do you think I need to rip up the flooring and install new flooring? Or, if left undisturbed, are they okay as is? Will the concrete eventually dry out? I was told that if they are left undisturbed, mold will not cause health issues. Once it is disturbed by ripping up boards, then the mold can become airborne and can cause major health issues. Is this true?

A: If this was a floor installed on a raised sub floor then I would recommend ripping everything out because a large amount of water can seep and stay under there for a long time and take quite a long time to dry out. In your case, the floor is installed directly on the concrete with no space. I think the amount of water under there is minuscule and will transfer through the structure and evaporate. Keep in mind most needs a certain environment to grow. That would be warm and moist. If you have gone through this with no apparent damage to your hand scraped hickory, I’d sit down and enjoy a pint or glass of wine in my favorite chair and breath a sigh of relief.

Poly lifting where dog peed on floor

Q: We have a satin finish on out oak floors installed 2 years ago. Recently my dog peed a puddle and it sat for maybe 3 hours before we soaked it up. Was not yellow pee she just can’t hold her water long anymore – now that it’s up. The seams in the poly have lifted and it is not smooth any more to the touch. Is this normal? I spoke to my sister who has 2 dogs and lots of accidents on her satin poly finish and she said it just beads up and floor is fine. Even when she does not see for a full day? Thank you in advance.

A: If any liquid sits in the middle of a board coated with polyurethane it will bead up, yes. However, it can still find a way below the surface along board edges and it sounds like this is what has happened with you. If these episodes become more common the uric acid will eventually start to degrade your floor finish.

Similar Q: My dog peed on my wood floor. It hasn’t stained but the boards are swollen and slightly lifted where she’s gone. Can this be fixed or does my entire floor need replacing?

A: I would leave it for now and see what it is going to do. Maybe it will settle down when it dries out. At worst a board can be changed.

Main level floor affected by basement flooding

Q: In August we had some water in the basement. The temperatures outside were outrageous, high 30’s with humidity in the 40’s. Once the water was abated the Insurance company aggressively dried the basement. There were 3-4 dehumidifiers and about 10-11 large fans. Immediately after the fans and dehumidifiers were removed I noticed that my engineered hardwood floors on my MAIN floor were starting to sound like dry timbers. It has only become worse over the past couple of months so I am not at all confident that it will “reverse” itself like I was told may or may not happen. The floors were only put in 3 years ago and this is a real P*@@off! Could this very well be from the amount of equipment used to dry out the basement? The kitchen is right off from the basement and it somewhat open concept. The kitchen opens to the dining room which is open concept to the living room, which is where the majority of the floor issues are. Thanks.

A: I have a few questions: exactly how much water did you get in your basement? What is the flooring down there? Do you have a raised sub floor? Is the engineered flooring glued or nailed down? Have you noticed any humps, gaps between boards or cupping where the edges of the boards are raised?

Follow-up Q: The basement had an even 4 inches of water throughout. All the laminate was ripped out. But the damage and my questions are regarding my main floor. After the drying of the basement, we noticed the main floor; engineered hardwood nailed down with high grade underlay, started to make cracking sounds when walking on it. Even the drywall coming up from the basement cracked from being dried out so aggressively.

A: Well having that volume of water being absorbed by the surrounding structure you will get expansion. Then as it dries out or equalizes there will be shrinkage. The nails or cleats used to secure your engineered floor don’t expand however. They may pull or stretch a tiny amount but after everything dries out you floor will not be as tight as it was before. The less gradual a round of this expanding and contracting is, the more severe will be the results. During this process, I think it may have been wise for the insurance contractor to be monitoring everything with a moisture meter.

Similar Q: I had my floors refinished on the main floor. Two weeks later the water heater in the basement flooded. A couple days after the flood, the hardwood flooring above the water heater area ruptured and cupped. Is this due to the moisture from the water heater flooding from below in the same area?

A: I would think it is caused by that. How long did it take to clean up the flood? This is unfortunate. The only thing to do with these cupped floors is to give them time to stabilize. Hopefully they might flatten out on their own. It would be a good idea to have a dehumidifier running in the basement until all moisture is removed. If you have a hygrometer in the area it will tell you what the relative humidity in the area is.

Follow-up Q: Thank you for your response. The dehumidifier took about 2 weeks to get all the water out of the carpet in the basement. That’s why I think the upstairs floors ruptured and cupped. On my house insurance, I’m having issues proving to them that my hardwood floors were damaged and affected by the moisture caused by the flooding in the basement and they require proof in order to include the upstairs floors that is cupped and damaged above the flooded area. What proof can I provide to the insurance company that the upstairs flooring was damaged due to the flooded floors in the basement?

A: Contact the National Wood Flooring Association. They have inspectors fully trained who will come to your house for an inspection and write up a report. A number of years ago I was installing oak flooring on a main floor of a very old house and I found out that they were having a new concrete floor poured in the basement while I was installing this hardwood. I was very concerned about the volume of moisture that would be hitting the subfloor I was installing the oak onto. They stapled plastic sheeting to the bottom edge of the floor joists in the basement before pouring the cement.

Water softener overflowed onto laminate floors

Q: My water softener overflowed 26 gallons of water onto our laminate floors. We cleaned up the water and ran a dehumidifier and fans. The flooring covers about 800 square feet of our downstairs. However, the water ran under the laminate and when we took the vent covers off of our floor and felt underneath it was still wet, and that’s across the room. The flooring is resilient grip strip plank. There appears to be no damage to the floor above but we don’t want mold growing under the floor. Will the water dry up on it’s own with a dehumidifier or do we need to replace the whole floor?

A: Can you take the floor up without damaging it and keeping each piece in order? It will have to come up or it will take a very long time to dry out the area under it and you will end up with mold. That is quite a bit of water and it has to go some place. The way it is now, it is mostly locked in under that floor.

Can a roof leak cause cupping in a hardwood floor?

Q: Hello, is it possible for a roof leak to cause cupping? For the water to go down through the walls and get under the floors? We have cupping floors and that is the only possibility for water damage. Thanks!

A: Yes it is very possible. I’ve seen that happen more than once. All I can suggest is locate and fix the leak and run a dehumidifier to dry out the floors. Once in a while they will actually flatten out. Unless you suspect a lot of water under the floor the best thing to do is leave it alone and let it dry out completely.

Follow-up Q: Thanks so much for you response. Do you have a suggestion for how often and how long to run a de-humidifier without over doing it? Thanks!

A: I don’t think you can over do it running a dehumidifier. Having a hygrometer in the home can be helpful. It gives a reading of temperature and RH in the room. This time of year an RH of 45-50 is normal. I installed unfinished oak once in a very old house in Toronto. This place was on the edge of a ravine, surrounded by trees. One day it was mid 90’s and the humidity level was over 90%. In a panic I told the home owner, who wasn’t living in the house yet, to bring a dehumidifier fast before it started raining inside the house, lol. I wouldn’t expect you to have a moisture meter but if you had one you place it on the floor and it will tell you the moisture content of the wood. 6-10% if fine. 15 and up is not good.

Humidifier flooded floor

Q: We left a humidifier running for 8 hours overnight and in the morning the laminate wood floors were soaked. We cleaned up all the water and there appears to be no damage. Should I still use a de-humidifier to dry it up?

A: If you had a pinless moisture meter to check the floor directly that would help but I know that is unlikely. It wouldn’t hurt to run a dehumidifier for a day and see how much moisture is captured. It is positive that there is no apparent damage at this point as I would expect the cheaper products to have curled edges soon after getting soaked. Some of the good laminates such as Torly’s claim water can be across the seam of at least some of their floors for 5 days without any water penetration into the product.

Temporary water leak and mold

Q: Last night my humidifier leaked a few cups of water onto the wood floor of my daughter’s bedroom. We discovered the leak maybe 20 minutes after it had started and we cleaned it up, but this morning I found a little puddle of water in my basement directly below where the humidifier had spilled. Is it possible the water went through the floor and the ceiling into the basement? What’s the best way to make sure the floor dries and doesn’t mold? Thank you!

A: Clearly that is what happened and it actually is a good thing. The water ran right through rather than pooling and soaking into the board edges. I wouldn’t worry about mold. It requires a constant moist, warm environment to thrive.

Follow-up: That’s such a relief, thank you so much for your quick response! I live in Seattle so mold is always a problem. I’m glad my floor won’t be damaged. Thanks so much again, I feel much better!

A: I’m guessing you are in an older home that perhaps has individual planks of pine for example as a sub floor? I’m guessing that because the water seems for the most part to have leaked right past the sub floor into the basement. If you had plywood subfloor for example (which is a good surface to work with) the water would have soaked that and it would have had to evaporate through the floor to finally dry. So, given the small amount of water, that it didn’t pool and you got right on it…I doubt you will even have any cupping of the floor. Even if you do, I’ve seen it flatten after. If you had an ongoing leak over a long period of time you might have a mold issue then. Not in this case.

Related Q: Our laundry room pipes burst in the cold and flooded down into our kitchen. The wood was sealed with two coats of stain and three coats of varathane, but the water sat for several hours and has gone through the cracks. The boards are now curved up at the edges in a concave shape.

We have been running 2 dehumidifiers, but it’s cold and water isn’t coming out. We have a gas fireplace and it’s running strong. I am worried about making sure the subfloor doesn’t get moldy. Thoughts? We think we can sand down and refinish the floor. Thank you!

A: For mold to be a problem, alive and growing it needs a constant environment of moist warm air. If the floor is installed on plywood that likely means it didn’t seep into the basement so it is sitting on the plywood surface and underside of your hardwood floor. Without actually removing the damaged section of flooring it could take some weeks to thoroughly dry everything out and you wouldn’t want to sand the floor until that happens. You will need a moisture meter for wood to keep checking until you get readings 7-9% or at least close to that.

Similar Q: Our window AC unit leaked water inside and onto our carpeting/OSB subfloor. We dried carpeting, ripped out padding and are drying subfloor with fans/dehumidifier. Subfloor doesn’t look bad at all. However, there is water damage on ceiling below from leak. Do we need to replace subfloor? Clearly it leaked through. What is likelihood of mold developing in between subfloor and ceiling?

A: You aren’t talking about a huge amount of water trapped which will take months to dry out. Mold needs a certain constant environment to grow and thrive. Constant warm, damp or wet environment. I wouldn’t worry about it. Just make sure everything is really dry before doing any painting or putting your carpet back.

Similar Q: Our refrigerator leaked for quite a while before we noticed the floor in front bowing. We have real Brazilian cherry floors. The floor man said to let it dry thoroughly and then he will lightly sand and then refinish. We live in South Carolina where it is hot and humid, I’m afraid that the sub-floor will be moldy.

A: Under the circumstances It may be wise to remove the damaged area and let everything dry out. I assume this is factory finished flooring. Jatoba does change colour rapidly with light exposure so expect to see a difference between the old and new wood which should change rather quickly.

Christmas tree stand leaked

Q: I just removed my Christmas tree and found out the Christmas tree stand leaked and caused swelling along a seam in my 3/4″ engineered hardwood plank. Is there anything I can do to make the swelled boards go back to their original state?

A: Just leave it alone, exposed to air and heat. Hopefully as it dries it will shrink. It might leave a small gap which can be filled with colour match filler sold in tubes and jars.