Multiple gaps running the length of the planks

Q: We purchased a new home in January (2 ft. of snow on ground!) The house had just had 3/4 inch thick x 5 inch wide oak pre-finished micro edge hardwood installed in an open floor plan: living room, dining area, kitchen and family room. This installation is above grade on plywood main floor, but with an unfinished basement below it (which is below grade and has a concrete floor).

No vapor barrier was used either underneath the oak flooring or on the ceiling of the unfinished basement. It looked great. Now in Sept., and a dryish summer (we’re in BC), the floor has developed multiple gaps running the length of the planks, that are wide enough to insert a 5 cent coin. What’s the best repair here?

A: Increase the humidity in the house.

Related Q: I recently purchased a house that had not been lived into for two years. The house is approximately eight years old. The floors were pine tongue and groove over what appears to be avantec sub-flooring. When the house was purchased the floors looked good, but had some of the finish flaking off. I had someone come in and strip and re-seal the floor prior to moving in. The work was done in Sept/Oct with no heating or air conditioning having been run for two years.

After approximately one month after the floors were done and the heating systems were turned on there are several boards in several rooms where the boards are cracking down the center of the board, and several other boards where the seams are coming apart. In the worst seam you can place approximately three quarters in the crack. These splinters and cracks between the boards were not there prior to the sanding and refinishing. Could it be that with the house vacant for 2 years that the boards had a high moisture content when the sanding and refinishing was done? How can this be remedied? I’m trying to find out what you think the cause could have been and what the possible fixes could be.

A: I would say the boards had a higher moisture content than they did after the heat was finally turned on. That is why they shrunk and gaped. Try to keep the RH in the home around 40%. Wood has moisture traveling through it all the time from it’s environment. The goal is to control how much. I don’t suppose the person who sanded the floor took any readings before sanding?

Second A (for some reason he answered the same question twice, and obviously had more time for the second go!): Pine is notorious for serious shrinkage. Now that heat if finally in the house the planks are shrinking. You can try to maintain a higher humidity level in the house. During winter months around 40% is ideal. You can’t go much higher than that, but don’t let it drop into the 20’s which is too dry. I doubt this floor will close up but it might be wise to wait until the humid summer to see what the floor is going to do. Then you could fill the large gaps with a polyurethane adhesive. There is a liquid form at Home Depot. You will have to tape the surface of the boards along the edge of the gap and crack because this adhesive will expand. After it has hardened, cut off the overflow to flush or preferably below the surface of the boards with a sharp utility knife and then use a colour match wood filler to apply on top of it. I suggest the moisture cure polyurethane adhesive because it won’t crack out.

Similar Q: I moved into a new condo about a year ago. The floors are floating engineered hardwood (non glue). They have developed small gaps at the seams, in different areas, at the top of the planks and at the sides. One was repaired in the past but the gap returned in the same place. Should this be happening? What is considered acceptable? Also, what do you suggest to repair the problem? Thanks!

A: I’m assuming these are click joint floors. It sounds like you have a low humidity issue. It must be significant to cause this gapping. Is it possible you have a hot spot in the concrete, perhaps from water pipes beneath?

Backsplit house/crawl space/humidity issues when considering hardwood

Q: We live in Ontario Canada and have a back split house in which we are thinking seriously about installing hardwood in the living room and dining room. The house was built is the mid 1970’s and it has that amber coloured mahogany trim incl. around door frames. The furniture in the house is french provincial. The only hardwood we could find that compliments the woodwork and furnishings is hickory (the stain the company uses really enhances the wood an brings in the colours in the rooms).

My question is about humidity. We have air conditioning, but only run it when the heat gets absolutely unbearable, because we really enjoy having the windows open in the summer. I’m concerned about humidity affects on the hardwood flooring. Fluctuations range anywhere from 30 to 60. Today it is 63. Should we be considering engineered hardwood or are fluctuations okay? Is hickory a good choice or should we considering another type of wood? Thank you for help!

A: Hickory is a very hard wood. However, it is sensitive to changes in humidity and will experience gapping. A much more stable wood as far as side to side movement is quarter sawn white oak. You can stain it any colour you like to achieve the look you are after.

Follow-up Q: Thank you for your reply. Can you suggest any companies that sell prefinished 1/4 sawn white oak hardwood flooring (some sites are referring to it as tiger). I looked at Mirage and I don’t think they do. Would you suggest engineered as well?

A: Engineered should be very stable due to it’s plywood like construction. The Mirage product is the best engineered I’ve used. Having said that, I’m not a great fan of pre-finished floors for a number of reasons. There is a company in Schomburg called Northern Wide Plank Flooring which mills quarter sawn. Farther north you might look at Stanley Knight Ltd. In Meaford.

Second Follow-up Q: My house is a back split and the crawl space has concrete floor that is 4 1/2 feet high and approximately 20 ft x 20 ft. We store Christmas stuff and luggage under there. It does have a sump pump hole at the far end and it is not insulated. Our living room and dining room sit above this crawl space. I have read that hardwood flooring can’t be laid down over crawl spaces- is this true? Based on information I have provided can I lay hardwood flooring in these rooms? Any information you can provide is much appreciated!

A: The living room is well above the crawl space which has a concrete floor. This space clearly stays dry or you wouldn’t be storing luggage in the space. You should be fine as far as the hardwood floor is concerned. Make sure the wood is acclimated in the room prior to install and check moisture levels between the hardwood and the wood sub floor, which should be within 4% points (the sub floor should not be giving readings more than 4% higher moisture than the hardwood).

What is the minimum temperature wood floors are safe at, that we can have our thermostat set at (when away)?

Q: We have a home in NC that we do not live in during the winter months. There are hardwood floors throughout the home. We do not want to pay high heating bills since the house is empty, but we also do not want to compromise the floors. What is the lowest safe temperature that we can have our thermostat set at / minimum temperature wood floors can take?

A: This is a difficult question, and one I have not yet come to terms with completely. I don’t think temperature is the main issue. I don’t think cold temperatures by themselves will damage your floor. I took a gamble when I lived in Toronto by installing quarter sawn white oak in an uninsulated but closed veranda. It was all windows with a dirt crawl space below. I left a small heater running to keep the temps above freezing. At night it likely dropped to mid to low 40’s. In the day, with the sun shining temps could go to the mid 70’s even on bitter cold days. However, the space did get an air exchange from coming and going through the door to the outside. Here is an explanation of vacant house syndrome.

Security -conscious vacationers, a homebuilder’s unsold inventory, whenever a wood floor is deprived of an air flow in the environment, it can and will misbehave. Sunlight through windows generates heat, lowers humidity, moisture vapor enters to balance, nights cool off, humidity builds and wood floors cup. Thermostats set at 60 degrees and outside, winter howls, heating system runs constantly with no moisture added, and floors shrink.

Avoid problems by leaving windows “ajar”, have neighbor air the house out occasionally. Treat floors as discussed under cupped, tented, or shrinkage cracks and only after environment returns to normal. Owner to pay.

The above commonly ask questions will help you and your wood floor contractor resolve some of the everyday concerns about wood floors. By no means is this a sure method or procedure. If in doubt, get a second opinion…

Lets just say you have a 5 gallon pail of humidity (moisture). In a cold house that bucket represents a higher level because cold air cannot hold moisture that well, so it will tend to condense on surfaces. Warmer air can hold a lot more moisture in suspension so this doesn’t happen. What are the sources of moisture inside your house? How well is the house insulated and sealed so outside moisture doesn’t get inside? How much sun exposure is there? Best I can say is keep the heat no colder than 50. what about leaving a dehumidifier running? You can have it run directly into a drain.

Follow-up Q: Thank you so much for your reply. We currently have the thermostat set at 65 degrees and we are being told that it is cold there right now with high temperatures in the 20’s. We have never lived in the home since we bought it last year with the hopes of renting it, which has not worked out. We will finally be moving there this July. So, I don’t know definite answers to some of your questions. I think the house is insulated fairly well. And, I think that it does get some sunlight during the day. I’m not sure what you mean by the sources of moisture in the home. We do have a dehumidifier in the basement that runs directly into a drain, but, I think it mainly runs during the summer months. I’m not sure how we would have the dehumidifier drain on the main floor, though.

Anyway, I’m still very confused, so any further input you can pass along would be greatly appreciated. I’m not understanding if it is better to have it warmer or cooler for the humidity levels associated with the floors. The floors are beautiful and one of the reasons we purchased the home and we would hate to have problems surface with them before we even move in. Thank you again for your time and expertise.

A: Sources of moisture? Well, for example a toilet! That is a source of moisture. As soon as people start living in a house, sources of moisture increase. We exhale moisture. We use the sink. We cook. I think I would empty the toilet for sure and shut off the water supply. I’m still consulting a few others on this. I don’t want to give you bad advice and it is a tricky question. Eliminate the possibility for condensation to form on windows, walls etc. and I don’t care how cold it is in the house. If it is as cold inside as outside and there is very low RH in the house, you should be fine with no issues other than perhaps some shrinkage in the wood. Of course, if it is below freezing, you couldn’t run the dehumidifier.

Here is something I noticed the other night. I have hot water rads and vertical blinds which were shut the other night across the front window. It is cold outside. I happened to pull on of the slats back to look outside and noticed water running down the window. Why? I decided to open the blinds part way to allow air movement and the moisture dissipated. Moisture laden air was trapped between the blinds and the cold window so I got condensation. Opening the blinds corrected the issue. Ventilation. Having nobody living in the house should greatly reduce the amount of moisture in the air. The lower the moisture the less condensing on other surfaces. Ventilation and dehumidification I think are more important issue than how cold it is in the house.

I will be back as soon as I have more information.

Follow-up Q: Thank you Craig for helping to educate us regarding this issue. As I mentioned previously, we are concerned about the house being vacant for so long and just don’t want problems with the beautiful wood flooring throughout. You are being so helpful and we will look forward to any other information you can pass along. I think I’m understanding now that it is best to have as low humidity as possible in the house from what you are saying.

A: I’m a member of a flooring forum, so I presented your issue and concerns there. Here is one comment I received:


I recently did an inspection on a home in Eugene, OR. The flooring contractor had done his due diligence and the 4″ BC was not installed before it had acclimated to the home and the dry subfloor. The $1.4 mil home was completed in July ’07 but was not sold and occupied until Aug ’08. during that 14 month period the builder, trying to economize, cut power to the heat source.

Within 60 days of occupation and consistent heating the floor, which looked “pretty nice” at the time of sale, began to shrink and cracks began to open. When I inspected the floor one year after occupation, in spite of the extensive shrinkage and gapping, the average board still measured .015″ wider than the original milled size.

My investigation showed that, during the year of vacancy and no heat, the average outside temp was 54.9 degrees and the average outside rh was 82 %. For the sake of argument, I figured conservatively that if the indoor temp for that period averaged 60 degrees and the rh only 65% each board (with an expansion co-efficient of .00300 for BC) could have expanded 3/64″.

The thing we are talking about is CLIMATE CONTROL. A consistent source of heat will counter-act the chaotic effect of winter sun coming through the window a few hours one or two days a week.

NWFA says that a controlled 30-50% rh and 60-80 F temp will allow for optimum dimensional stability.

A problem with the vacant house syndrome is not only the cold and damp but the unregulated temp swings and shock treatment of the wood that come with periodic bursts of sunshine through the windows. Unofficially, I kept my Willamette Valley (read moist) warehouse 2-4 degrees warmer than the outside temp and never had a problem with any wood I stored there.

I guess the question for your concerned party is how much are they willing to spend to protect their investment.

Does that help to clarify? NWFA feels the temps should not be lower than 60 with RH kept between 30 (which seems rather low to me) and 50% (which seems high to me for winter heating season). I think in winter we should try to keep the RH between 35-42% at about 72F.

Follow-up Q: Thank you so much for all of this information! We currently have the heat temperature set at 62 degrees. So, I’m assuming from what I just read here that we are within a “safe” range. I really don’t know what to do as far as figuring the humidity level.

A: You can buy a hygrometer from Radio Shack etc. or Sears for about $35 which gives you the temperature and RH. Just set it on the floor for half an hour and see what the conditions in the room are. This is a sticky issue for sure. I think I mentioned I installed quarter sawn white oak plank in an enclosed, non insulated porch but left a tiny heater running all winter, just to keep in in the 40’s F range. It would get into the 70’s on the coldest day with the morning sun. So, I had swings in temperature and never had an issue with the floor, but that cut of oak is more stable than flat cut. I think you are fine at the temperature setting you have.

Related Q: We have factory finished hardwood floors. If we leave the house for four months in the winter, what temperature should we set the thermostat on to protect the floors and wood cabinets?

A: I wouldn’t drop the temperature below 65F, and in winter try to maintain a RH level between 35-40%. I would have someone come in once a week to check that everything is OK and let some fresh air in.

Humidity and wood floors

Q: I recently moved into a newly built log home in Northeast Ohio. I have hickory floors. The floors were put down in the dead of winter (January) and the humidity in my house was very low. By May I was having a problem with the floor, wavy in some areas and actually buckling in one room. For the last two weeks I have been running dehumidifiers, ceiling fans, and the air conditioner to try and bring the humidity down, but it almost seems like the waviness is getting worse not better. I understand that the humidity should stay as constant as possible, summer and winter, but what is the ideal humidity for wood floors? The man who installed my floor is telling me 30%, but it seems like I can’t get it there. Any clues on what I could do?

A: I have to assume that this cabin is heated in winter. Humidity is a tricky question and the figures that some companies recommend seem unrealistic outside a laboratory. For example, I have read to keep the RH in the home between 45-50% year round. We could not allow that in our climate! In the winter, we would have streams of water running down the windows and walls. I heat with forced air and in winter it is typically RH 33-40 in my house. I don’t want it dropping any lower or going any higher. I think your installers number of RH 30 is unrealistic for our climate, especially in summer. You couldn’t keep it that low.

I think this is the best work around. When installing in winter with heating in place and typically low RH in the home, a humidifier should be running at that time of year to raise the RH to at least 40%. Like I said, you can’t go much higher without creating condensation issues. But, at least you won’t be under 30% and then face a huge swing when spring comes. If a humidifier had raised the RH in winter when the floor was installed, then you should be able to keep it down to 50-55% in summer. I have one of these digital dehumidifier’s running in my basement and I can set it to any figure I like. It can handle 3000 sq. ft. and does a good job. So, if the floor was installed at about 40% RH in winter and now in summer it rises to 50-55, that is only 10-15% difference and shouldn’t cause a problem.

Here is another factor that can come into play when installing at low RH in winter: You take the wood into the house and let it acclimate. It is dry in the home so the wood shrinks a bit. The wider the board, the greater the expansion and contraction. The floor is installed and nailed nice and tight. You have to know that in summer when the RH increases 30-40% or more, the floor is going to expand. It is absolutely imperative that an expansion gap be left around the perimeter to facilitate the expansion. If the floor is installed tight to the walls in winter, when it expands, something has to give. I would check the floor along the walls. If it is tight, you may have to remove that row of boards or find a way to cut it back to allow an expansion space.

I hope some of this is helpful. Hopefully this floor can be gotten under control and it will settle back down without any repercussions.

Could drought be causing the popping in my floors?

Q: My hardwood floors have developed a lot of popping/cracking sounds in recent weeks/months. I just saw on Weather Channel that people’s foundations and brick walls have been damaged from drought, and my state has had the worst drought in the nation for months. Could drought be causing the popping in my floors?

A: Excessive dryness would also cause excessive shrinkage in your floors and could create such sounds as the floor moves. You may try to add some moisture to the air if possible.

Turning off the heat when away during winter?

Q: We go away in the winter. I have ash floors and would like to turn off the heat while away. I live in NH and the house could get down to 30 degrees. Would turning off heat affect my floors? I have been leaving the heat on 60 degrees in previous years and there is some shrinking, but the floors expand in the summer with no problems.

A: That sounds fairly risky to me. You may end up with the opposite problem. Instead of shrinkage, if the humidity should rise you floors may end up cupping. I think I would leave the furnace at 60 and have a neighbour come in a couple of times a week to let in some fresh air.

Similar Q: We just installed 5″ Brazilian tigerwood in our vacation condo in Chicago. We visit once a month, therefore we have been setting the temperature on a controlled level, but our last month’s electric bill was 6 times higher. Is there another option besides keeping the heat on? Is there a rug or something to lay on the floor to protect it from the cold while we are away?

A: I would be more interested in trying to keep the humidity levels between 35-40% RH or so.

Checking concrete floor for moisture

Q: I just purchased a small 2 bedroom home that has carpeting over a concrete floor. We are at ground level and want to lay hardwood flooring. What actions do we need to take prior to the installation to steer clear of moisture damage? Do we just lay some sort of moisture barrier or do we have to lay plywood?

A: I would tape some plastic sheeting in various parts of the concrete and leave it for several days to see if you get any condensation on it. If this is going to be a nail down solid floor you will certainly need to lay plywood. If it is engineered or a click joint type floor, you won’t. Engineered can be glued with any moisture proof adhesive such as Bostik’s Best or TKO to name just 2.

Unoccupied home detrimental to hardwood floors?

Q: Why is leaving a home unoccupied so detrimental to hardwood floors?

A: I can give you one scenario. A house has been purchased but not yet lived in. A new floor is installed under this scenario in cold weather conditions. The relative humidity in the house drops significantly. Just having people living in the house could alter this significantly. Every time we exhale, moisture is released with every breath. We flush toilets. We have a shower. We wash dishes. We cook. We do our laundry. All of this activity in the house provides some moisture to the entire structure. Without that, everything will dry out and shrink.

Planks developing a ridge, lengthwise

Q: 11 Months ago I had an engineered hardwood floor installed in a high rise condo. After 3-4 months I noted each plank developing a ridge lengthwise, and today it is quite pronounced. It can be felt underfoot. I have called the manufacturer. The rep came and did tests. He said it may be from the air being too dry although my barometer said 30%. I have a humidifier, but do not have it on now. The problem is worsening although rep said it will be better in summer, but not so far. The manufacturer rep said he would get back to me, but it has been over a month so I doubt it. The installer has referred to manufacturer. What can I do as I do not want a floor with these ridges and warranty is out end of June?

A: If by ridges you mean the edges of the boards are lifted up, I would say this sounds like cupping, and is not caused by dryness, but excessive moisture. You don’t have anything leaking, do you?

Follow-up Q: I am in a 1300 sq. ft. condo on the 23rd floor. I had 1000 sq. feet installed. It is not in the kitchen, bathrooms or laundry area.

I noticed the floors last fall and over winter it has progressed to worsen. It continues to do so. Right now it is noticeable even in my walk-in closet.

Nothing is leaking. My furniture is not suffering from any dryness or moisture.

What am I to do?

The rep from the manufacturer came and did some tests over a month ago now. He said he would get back to me in a couple of weeks! He said, as he left, that this will right itself by May 24th as that the summer humidity will put it right. He said the air was too dry, in spite of my humidifier (and the reading was 30%.)

It has been humid as we do not have the air conditioning on until May 31st– building policy. Some law states the heat must stay on until May 15th, but of course, it is shut off in my unit. We have individual controls.

I look forward to your comments and advice. I did not mention the company, but it is a large well known manufacturer of hardwood floors.

A: Are there any gaps developing between boards?

Second Follow-up Q: No there are no gaps, thank goodness. Just the rising ridges lengthwise. The widths remain nice and smooth as when they were when laid. Just in the light and the shadows, all one can see are the ridges, and not the beauty of the fine wood floor any more.

A: I would have to put this down to swelling of the board, and possibly a lack of expansion space along the walls. That is my guess. I’ve never heard anyone try to pass this off as being caused by too low moisture content. If that were the case, the boards would shrink, and you would have gaps.

Third Follow-up Q: Can you tell me the best avenue to take to resolve this? Is there an outside body/regulators, or an arbitrator, to come to some kind of solution? I would like to contact them if the company and the installer will not do anything further.

A: First, I would go to a web site, such as or any other that answers questions. Find their answer as to why edges of boards curl upward, which will verify that it is not caused by lack of moisture. If the company is a member of the BBB, they will serve as an arbitrator when a dispute arises. They recently contacted me about becoming a member and I rather liked that aspect myself.

Dirt basement and moisture issues

Q: My hardwood floors were refinished 4 years ago. In the past year the floor is darkening, and there is separating of boards. There are smaller, darker circular areas. Mostly in the living room, which was carpeted for many years, but also in bedroom which was refinished many years ago. Some of boards are separating in the living room, and I can feel a slight bowing. My basement is dirt – house built in late forties. Few of boards appear to be eaten. Termite inspection last year revealed no termites, but moisture.

A: You need to deal with the moisture issue. Laying a tarp over the dirt might help.

Hardwood floors in basement

Q: My home is located in the Kansas City area. I am currently in the process of finishing the basement. My wife would like to have hardwood floors. My main concerns in using a wood floor is moisture, the cold feel, and losing headroom from a built-up floor. I intended to use a subfloor material and install a floating engineered wood floor on the subfloor. I am considering two products to use as a subfloor for the wood floors. The two products are Delta FL ( and DRIcore ( Both products are similar in that they use high density polyethylene (HDPE) as the vapor barrier. The major difference is the DRIcore product a 5/8” wafer board attached to the HDPE and per the Delta FL website, the wood floor can be installed directly on the HDPE. Do you have any experience with these products? Which product do you recommend or is there a better method?

A: Unless you have a serious water infiltration issue into your basement, a floating engineered should be fine. I am not an expert on Delta or Dricore. I am somewhat familiar with both. Basically Delta is Dricore without the chip board surface and comes in rolls, whereas Dricore comes in 2X2 squares, as you mention. It seems a bit of a coin toss. If you lay down the Delta, I think you will still need to install a plywood sheeting. It seems to me that the way to go will depend on how you see your basement floor changing over the years. If you think the floater is not a long term floor, and eventually you might go with something even better, you might want to go with the Delta and real plywood over top. something you can nail to. If not, the Dricore might be a better choice. What I don’t like about Dry core is that there are 4 joints every 2 sq. ft. The more joints in a sub floor, the more potential for problems.

Q: Thanks for your reply. I do not think that moisture will be a problem in my basement. Prior to staring construction on the basement, I did apply a deep-penetrating reactive concrete sealer on the walls and floor that claims to penetrate deep into concrete (up to 4″), chemically reacting with lime and alkalis, and hardening as a mineral. I did notice considerable difference after the concrete sealer application, there was not longer a moisture smell. So with that being said, would you recommend installing a floating engineered wood floor directly on the concrete slab? What (friction/sound) foam layer would you recommend? Is a thick foam like “Quiet Walk” better?

A: If you installed a Torlys or Uniclic floater, they actually have their own pad which they say you must use. It serves as a vapor barrier, complete with overlap and tape and gives cushion to the floor. If you feel confident in the concrete, go for it. The worst that can happen is you lose the floor.

Installing wood, over cement, that’s over wood?

Q: We have a wood floor covered in a cement slush which is about an inch thick. We want to go over the cement since it has asbestos glue on the cement. The two contractors we’ve spoken to are encouraging us to put down plywood and then solid hardwood on top of that. We are also considering putting down a floating engineered floor with a sizable veneer. Which would you recommend?

Also, for an entrance way on the east coast, would wood be okay provided we wipe our feet on an inside mat?

A: I don’t even like the sound of this at all. All wood will absorb and release moisture. It will expand and contract. I don’t know how you could have a wood structure covered with cement and not expect stability problems. I would remove the entire mess down to the lowest sub structure and start over.

Follow-up Q: The house is a city house in Philadelphia that’s probably from the early/mid 1800s. It was once a restaurant and bar and they covered the wood floor with tile using glue with asbestos. A few months ago I ripped up the carpet, found the tile, and used a chisel to get the tile up. There is just a film of dry old glue on top of the cement slurry. I was told from a couple of floor guys who’ve been here that the glue with asbestos is not dangerous in solid form. It becomes dangerous if we were to use a power tool that would create air-borne, harmful dust. We’ve been told the best thing to do is not to disturb it and cover it with wood. (You see, my intention was to get down the original wood floor – no such luck). Do you agree?

A: I need to try to understand exactly what is going on here. Are you saying that there is a thin layer of cement sitting on or over a hardwood floor, and that tile was laid on this cement? You now have the tile up, and the thin layer of cement remains, covered in adhesive. How do you know there is a hardwood floor under the cement?

If there is, I have my doubts it could be salvaged now. And given the issue of asbestos, I think you would be wise to leave it undisturbed. I would screw down 1/2 plywood at least and install a floor on top of that. My choice would be 3/4 solid, unless you have a height issue that cannot be reconciled. There are some good engineered floors on the market with a very thick solid wood veneer. Mirage engineered is one of them. You could sand and finish such a floor about as many times as a solid 3/4, yet it is only half the overall thickness. I am not a huge fan of prefinished floors. If that is the type of engineered you had in mind, keep in mind that the day it has to be re sanded, the micro bevel will also have to be sanded off. I am ok with hardwood in an entry, provided the floor is well finished and you have a mat in place and wipe up any water over run right away. If the mat gets wet around the edges, eventually it will blacken your floor. I prefer ceramic in an entry way.

Tropical climate and wood floors

Q: We just installed N**** Floor Planks and parquet in our basement. We stained the wood and put dead flat finish as topcoat. It was 99% done, when some hairline cracks appeared, there were around 10 at first, but as the days progressed it multiplied. We sanded those parts and re-applied the top coat, but a day later, the cracks resurface and expanded? Is there a remedy? I am based in the Philippines.

A: You are in a tropical climate. That means high humidity. I am surprised the floors gapped. I would consider it normal, and if they are hair line cracks, I don’t think I would worry too much about it. The floor will likely change with the seasons.

Related Q: I live in Tunisia where the temperatures can reach up to 48°C. Will this excessive heat affect laminate wood flooring? Any issue with tropical climate and wood floors? Many thanks.

A: A bigger issue is generally humidity, not heat. I would check the product recommendations and compare them with where you live.

My hardwood is glued directly to concrete, no vapor barrier

Q: If my hardwood floors were installed poorly…. My hardwood is glued directly to concrete, no vapor barrier, and there is no 1/2″ gap between floor and wall. How much moisture is needed to cause cupping, or worse, buckling?

A: If the moisture in the floor or coming up through the concrete is higher than the moisture content in the flooring when it was installed, it will impact the floor. That is why there are products and procedures to block or retard moisture movement, so it doesn’t hit the wood floor in one continuous stream.

Wood floor pops in winter

Q: We had engineered oak hardwood glued down to our concrete subfloor in the lower level of our back split. It was done by a flooring company. They said the glue would allow the wood to float. It has been in 3 years and the only problem is that in the winter there are certain parts of the floor that pop when you walk on them. It is not in all areas and only happens in the winter. During the warmer months I don’t notice any play in the floor. The edges of the strips are not buckling. Are wood floor pops something that we should worry about?

A: If it has been down 3 years without buckling, I wouldn’t start to worry prematurely. It might be that there was a bit of a recession in that spot that makes the noise and there wasn’t a good grab between the adhesive and flooring. I would try to keep the RH in the home between 35-40% in winter.

Wood floors drying out the air?

Q: Our landlord just installed new oak floors in several rooms. They are beautiful. But ever since their installation, we have VERY dry air in the house and cannot get past the choking feeling in the air, despite running a humidifier as much as possible. How long will this last (it’s awful during this flu season)? Any recommendations to help the floor to “settle in”?

A: The floors have absolutely nothing to do with causing dry air in your house. I will say that very dry air can cause excessive shrinking in the boards, especially so if the cause is seasonal and you have hot water radiators. Adding humidity is a good idea.

Bamboo gaps?

Q: About 3 months ago I had bamboo installed in my second story bedroom over a plywood subfloor. Unfortunately, after a month of being installed 6 gaps opened ranging in size from 1/16″ – 1/8″! Prior to installation I unpackaged the wood, stacked it crisscross, and let it acclimate for about a day and half (I thought I was playing it safe). Then a cold dry spell hit right after Christmas, accompanied by some strong wind that gently shook the second story. Before I knew it, I began to hear loud CRACK noises as the wood contracted and pulled itself into new positions. The installer used the “hidden nails method” and also put wood glue in between the slots, so I suspect the cracking was the sound of the wood glue seals being broken.

How can I fix this? Is puttying my only option? How will that look? Will the wood expand in the summer (I live in SoCal). If it does expand, will that screw up my putty fix?

A: I think I would let this floor go through an entire cycle before doing anything. Several years ago my 70 year old oak strip developed large gaps in winter, the size of which I had never seen with it. I got a humidifier running, and they closed up.

Bamboo hasn’t really taken off in the Toronto area yet, so I am not very familiar with it. I can say this. The one floor I saw installed and every single sample of it in flooring company show rooms had large gaps between each strip. I wasn’t impressed by that.

Follow-up Q: I’ll do as you suggest and give it a year to settle down. Assuming the gaps still need to be filled later what would you recommend that I fill them with? I don’t want to refinish the floor, just fill the gaps. Is this possible?

A: I have used a good tube filler called color-rite. Comes in hundreds of colors. It is more like a caulking. Water clean up.

Moisture ratings

Q: I am having hardwood laminate installed over radiant heat. The tubing is installed in a grooved plywood track on top of the sub floor. The maximum inlet temperature into the loops is approx 108 degrees. There is a 20 degree temperature drop so the flooring will only see about 88 degrees.

The flooring as I understand it has a moisture rating of between 8-10. My heat designer said they recommend between 6-8. I have the new flooring laying on the radiant heat (in boxes) for about a week.

I don’t completely understand the moisture ratings but do you forsee any problems with this installation as far as expansion and contraction?

A: I don’t think you will have a problem, but if it was my job, I would probably contact the product manufacturer, or check their web site. They may very well have a data sheet giving all the needed statistics.


Q: I live in Alberta, and have had solid maple hardwood flooring installed over a new sub floor of 5/8″ plywood on my main floor. The strips were nailed securely and tightly by a carpenter friend who has done this before, and his floors always looked great for years after, so I know that he is doing it correctly. By the way, this flooring was reclaimed from a 55 year old house about to be demolished. The flooring was acclimatized in my house for a period of approximately six weeks before being installed.

I did bring in a professional hardwood floor sander/refinisher to finish the floor. It was only after the sanding and two coats of oil-based urethane were applied that I noticed and became concerned about the gaps between hardwood strips. I obviously had not checked closely before the refinishing began, so my mistake. I can only guess that being in this part of the province during the heating season, the humidity level was so low that the hardwood shrank appreciably.

My new furnace is equipped with a Generalaire by-pass humidifier, but unfortunately it was not connected during this whole process.

So, now I have halted the final finish coat on the floor, and have the humidifier working at a maximum setting.

It has now been three weeks with the humidifier working at a high setting, and I’ve been hoping that I would see a reduction in the gaps between some of the hardwood strips, but my close inspection reveals no change whatsoever.

I expect that the person I contracted to sand and finish my floor should have asked me prior to starting the job about humidity, but all he asked was whether the material had spent some time in the new environment before being nailed down, which of course it had.

What is my best strategy for getting this flooring to swell back to what it was when laid? My understanding is that finished and sealed solid hardwood floors will swell and contract with humidity changes, so is it not reasonable to expect that raising my relative humidity level will have this effect on the wood? Or should I just have the gaps filled, more urethane applied, and then hope that it will not expand later and cause me grief with the filler material breaking up?

I have considered getting a hygrometer to see what my humidity level is, and try to ensure that is 40% to 50%, but have not done so yet. I would very much appreciate any advice or thoughts you may have on this situation.

A: Interesting situation. First, I really don’t think you can blame the floor sanding company. They really have nothing to do with the gapping. If anything, applying a polyurethane coating to a floor would slow moisture movement from beneath the floor and cause the floor to expand if there was to much moisture, for example, coming from the basement. I do not think we can keep the humidity levels at 50% in the colder parts of Canada in winter without having moisture problems all over the house. You might want to check the environment below the floor to see what the readings are there.

Wood floor popping when the furnace comes on

Q: I’m having a problem with my wood floor popping when the furnace comes on and run for 30 minutes or more. I am getting this very loud popping in the flooring, is that a natural occurrence when the weather out side changes or is that something I need too be concern about?

A: I’ve heard of this a couple of times in my career. Probably the floor contracting a bit with the dry air from the furnace and either stretching the polyurethane coating, pulling away from such that had soaked into the joint, or, if it is a very tightly milled floor (tongue and groove joint being very snug fit) it would make such a noise as each adjacent piece pulls slightly away from each other. Shouldn’t be anything to worry about and should stop after a short time.

Follow-up Q: Whew! I thought I was dealing with something major. I just brought the house about a month ago and I have the paper work on the floors. It appears that the floor was installed in 1998. Is there anything I can do to make this noise stop, like a humidifier?

A: I think I would suggest buying an inexpensive hygrometer from an electronics store, which will show the temperature and relative humidity in the room. A humidifier may help. It is a tricky subject though. Floor manufacturers would tell us to keep the humidity in our homes between 45-55% or so. this would be impossible in Toronto in the dead of winter. I would have rivers of water and ice streaming down my windows. No higher than 40 in winter I would think, and don’t let it drop below 30. Hope that helps.

Related Q: I noticed that some people have written to you about floors that pop when the furnace or air conditioner go on. My house is fourteen years old and this is still a major problem. The popping continues for a good amount of time even after the blower turns off. If I ‘jump’ on the areas they will quiet down for a short while, and then it starts all over again. It’s bad enough that it wakes me during the night, and it is throughout the room. Any suggestions would be greatly appreciated. Thanks so much!

A: You probably need someone to come and inspect the home. Perhaps someone from the National Wood Flooring Association. I’m sure they will take a trip to the basement to look at duct work routing etc. Clearly this should not be happening after 14 years of a floor being installed. Something is causing rapid changes to temperature and possibly moisture and likely from beneath the floor.