The Flooring Expert

Q: I am wondering how to add IIC ratings for two different materials, as I know that I can't simply "add" them together for the total score.

Hope you can help me!
Alia

A: Most IIC ratings for wood flooring underlayment is calculated with a layer of 5/8" bare plywood laid over the top of the underlayment to act as a pseudo floor. This means the ratings should be pretty accurate to what you will get with a finished floor over the underlayment. The primary difference you get between carpet and hard surface flooring is that your feet impact the hard surface first with a wood floor, where as with carpet that impact is cushioned before hitting the subfloor's hard surface.

If you choose to not wear shoes over a wood floor there will be an audible difference in your condo, but overall the impact transfer should be roughly the same going to other units. If you want the room itself to sound quieter, walk around in socks and it will reduce sound quite a bit. This is especially the case with high heeled shoes as they are very noisy over wood floors and can cause denting, so avoid wearing them when possible. Overall, if you have concerns about your condo board, you could combine underlayments, such as using 6mm and 3mm cork or 6mm cork and sound 6, but typically this is overkill for most condos and 6mm cork tends to be enough or various other underlayments out there which are denser modified-foams or rubber.

Q: inherited a 10 year old laminated floor. it was placed over tile. don't know more of history. previous owner had metal strips as thresholds between laminate and carpet. wanted to replaced the metal with more attractive wood strip. found could not glue threshold to edge of sub-floor beneath the laminate because edging of laminate is uneven, not squared or consistent. have used screws to hold wood strip in place.

is there a way to solve this creaking sound? replacing the laminate, even a small section of it is not an option....a match can't be found.

A: If the screws are going through the laminate that is your problem. Laminate is a floating floor, which means it is not meant to be anchored to the subfloor at any one point. If it gets anchored at one point, then you run into the exact problems you are seeing, as the floor shifts ever so slightly raised areas and noise occur at the anchor point.

Your best course of action here would be to remove the screws and transition strip and replace with an overlapping transition which uses a track system. Use liquid nails to install the track to the subfloor, allowing a small gap between the track and floor so the floor can shift. Then snap the overlapping trim in place and it should cover the expansion gap and a portion of your floor.

Q: As a "floating" product what are the weight restrictions for Konecto plank flooring ? ie; furniture, free standing kitchen islands, refrigerators, stoves, and in particular free standing hearth & wood stove with a total weight of about 600# ? I have 1/4" separations of planks around the wood stove area. Floor was professionally installed - and now they are going to replace/repair. No one seems to know if there are weight limits - they say not but it doesn't make sense to me.

A: If this is only happening around the stove, I'm willing to bet that this is a matter of environment. With the Konecto line, the adhesive in the seams remains somewhat active so that planks can be removed and replaced at any time and heat could cause this adhesive area to lift away when it normally would not with the weight on the floor.

Now if your stove is one where it has very few contact points to the ground, rather than a larger base, and it happens to contact right near a seam this could be another issue, but typically a 250lbs. roller is used to ensure that floors like Konecto are properly laid down, so it should be able to handle 600lbs. worth of weight.

Your best bet would be to contact Konecto directly and ask for their load bearing information. Most vinyl floors can handle quite a bit of weight, but the best source is always the manufacturer.

Q: I am opening a dance/yoga studio and of course, on a shoestring budget! I am interested in bamboo for ecological reasons, and wonder if you know if it is a good choice for this use.

Christie
in Hatfield, Mass.

A: Most dance floors nowadays are sold as kits and the typical surface, much like most basketball courts, is maple. Most commonly these are sold unfinished so that the floor can be sanded flat and site finished after installation to ensure there is no area with variance in floor height and to ensure a finish formulated for this traffic level is used. There are some other kits out there that use a tile like set up or larger floor piece similar to sheets of plywood in size which are done by professional dance studio finishers. Does this mean a sprung bamboo floor can't be done? No.

If you were to go with bamboo you would need to use something other than the traditional 3' planks. These are simply too small and the slight flex the floor has would be murder on the floor. Your best bet is to look into a floating product, as these are naturally built to flex slightly. Look into something like Springwood's click-together line and use a 3mm cork underlayment as this will maintain enough support under foot to prevent the floor from being too springy, while giving just enough flex to cushion movement as the sprung floor is intended to do.

Keep in mind that most dance floors receive regular finish schedules, where the floor is re-screened or refinished every couple of years (depending on traffic levels of course). In you case, screening will become something for your floor to keep the finish look good after a few years of use. I will caution here that if you choose bamboo, go with a natural bamboo as it is more likely to resist denting than carbonized and if you intend to have folks in high heels (ball room rather than ballet dancing for instance) then you may want to look into a more resilient species than bamboo as high heels will cause denting to bamboo over time.

Another ecological choice here would be something like an engineered cork. I know several yoga studios which use cork and now swear by it for comfort, but this can be a matter of taste as cork has some very unique appearances that might not fit what you are trying to achieve.

Q: I'm a new condo owner and would like to install hardwood (like the BR-111 Engineered Tigerwood or Triangulo Tigerwood). The builder didn't offer hardwood on the main level, citing the need to minimize noise transmission from my unit to the unit below. However, there's nothing in the building codes or condo bylaws to restrict the use of hardwood, except a line about "flooring must be replaced with the same type (e.g., carpet) and quantity (i.e., square footage) as originally installed."

I've known a few other owners to replace their floors without problem, although they bypassed the builder and the condo association. But I'd like to get condo association approval to avoid any risk.

It's a 4-story, townhouse-style condo (a 2-story unit over another 2-story unit), with wood frame construction and a gypcrete subfloor (ugh). The base carpet/pad is a 25oz plush carpet with a 6lb pad.

I noticed in a previous post that you suggested using Sound 6 plus 6mm cork underlayment. Assuming I opt for the BR-111 engineered Tigerwood, is this the underlayment you'd suggest for me? What about PadTech FloorArmor, or Maxxon's own Acousti-Mat II, or one of the million other rubber underlayments? Shouldn't the gypcrete help to isolate the sound as well?

Should I float the floor? Or attempt a glue-down installation? Is one better than the other for sound transmission/impact isolation?

What combination will make the engineered floor sound more like a 3/4" solid (to me)? I've noticed that laminate floors (at least in the flooring showrooms) can be much more "clicky" than the solid floors.

I'm hoping that I find an underlayment/installation method/hardwood combination that can achieve STC/IIC ratings similar to the base carpet/pad installation. That way, the condo association would have little reason to deny the request. I'd really hate to spend $15,000 on hardwood floors and then have to rip them out.

-J

A: Going through a process with your condo association ahead of time is a very good idea. In order to do this, we will need to dig up some information for the carpet currently specified to go into your condo, then compare them to the ratings for hardwood underlayment.

Its tough to find builders who are willing to glue to gypcrete. Although most gypcrete is approved for glue down by the manufacturers, but there can be some issues with it when it comes to adhesive curing because gypcrete will absorb more moisture than normal concrete - thus making the curing process for adhesives or thinset mortars different. So I would suggest going with a floating floor, and thus we'll do the numbers based on use of floor and underlayment in a floating system.

With a bit of digging I was able to find some STC and IIC testing on carpet, which I will admit has been tough to find in the past. Let's first discuss what each rating means, and how it will matter to your Condo board. STC or Sound Transmission Class, refers to the amount of sound absorbed by a partition or in our case, a floor. This typically applies most to air-born sound such as conversation, music, etc. IIC or Impact Isolation Class, refers to the amount of sound created by impacts, such as walking, which is reduced by a floor. It is important to pay attention to both of these ratings when it comes to sound control for a condo.

We'll start by comparing some IIC ratings. Now with a hard surface floor, such as the BR-111 floors you are looking at, they have very little IIC when compared to carpet, so you are relying on the underlayment to make up for this. 6mm cork, over a 6" concrete slab subfloor produces an IIC of 23 on its own, furthering the concrete's IIC of 27 to give a total IIC of 50. Your gypcrete should give very similar results, which means 6mm cork is roughly equivalent to another 6" of concrete.

For the carpet's IIC, a 25oz carpet on its own over concrete provides an IIC of 22. Carpet padding is just as varied as hardwood underlayment, but most pads tested provided roughly 5 - 10 IIC, with the median being about 6 IIC. So using the same concrete slab, that would give us a total IIC of roughly 56. If we used a more premium carpet pad, this can be pushed upwards of about 60 or so IIC. Overall, very similar IIC ratings between your basic 25oz residential carpet with pad and 6mm cork.

Now let's look into an STC comparison. Our 6" concrete slab has an STC of 27, much like the IIC. 6mm cork's STC on its own is 24, which gives us a total STC of 51. The carpet STC data I found is based on a wooden subfloor over joists with a suspended ceiling unit made from gypsum board. In similar tests with concrete subfloors, the suspended ceiling unit provided and additional STC rating of 14. wood over joists style subfloors will typically differ, and no data was provided for the raw bare floor's STC rating, but we can speculate that this will be somewhere in the range of 20-24 total, including the suspended gypsum ceiling piece to represent the ceiling below the wood subfloor. The overall STC rating provided by the 25oz carpet with a 1/2" thick 6lbs carpet pad was 49. With some quick math that means basic 25oz residential carpet with a typical 6lbs pad is going to provide an STC of roughly 23-29, but to be safe let's assume its going to provide on the higher end and go with 29.

This would put 6mm cork pretty close when it comes to both STC and IIC ratings versus our basic carpet and pad which is why we so commonly recommend it for condo owners. As you mention, there is a myriad of underlayment out there, some of it is great, others not so much. Personally, I am big on how a floor feels when I walk on it, which is part of why I am such a big proponent for cork, it just feels more like a solid floor under your feet than any foam underlayment - even the best stuff like Sound 6 and similar modified foam underlayment.

When you walked over the laminate, part of that hollow or "clicky" sound is due to lack of good underlayment and also part of the raw thickness of the floor. A 3/4" solid is just that, a thick, solid floor so it will sound more like it, whereas laminate is much thinner, normally 8mm - 10mm in thickness so the sound just has less it has to travel through. Now this gets alleviated by good underlayments, which is why we so commonly suggest against cheaper, foam underlays as they just don't perform as well. So, what's the best set up for you and what will pass your condo association needs while also fitting your own wants?

First off, your looking at a couple of very good floors, personally I'm a fan of the triangulo as it is a very good floor and can be installed as a floating with a 5" wide plank - so you get an easier install method and a nice wide plank to make sure its very stable. Combine this with good underlayment and it will both sound and feel like a nailed down solid hardwood floor. If you look into other products, find ones with substantial plies, thicker plies can be very nice for getting that solid floor sound.

For underlayment, I would suggest going with 6mm cork as a baseline. If sound is your primary concern, using 6mm cork as a substrate with Sound 6 over the top is a great option, but you will get a bit more movement in your floor than using solid cork. Another option would be 12mm cork or 6mm cork with a 3mm cork layer over the top if your concerned with overall floor height. This secondary option keeps the more solid feel under foot while beefing up the IIC and STC power with a bit more cork. 6mm has met all basic condo standards that we have encountered in the past and the regulations would have to be very strict to rule it out - so adding onto it should put you in the clear, but checking first is always wise. On any of the other underlayments out there, make sure you get STC and IIC test results to get the real ratings for them as this will help you compared them to other underlayment options.

Q: Can I use a irobot to clean my laminate floor? If not what is the best way to clean them?

A: Tough question, and technically the answer here is yes and no. Before we get going, I do want to say that these little guys are pretty cool. The Roomba, being the most well known of the iRobot line is quite the little invention and a few folks around the office here love theirs.

Now let's dig into the question. iRobot specifically states their scooba (the floor washing version) is safe for sealed wood floors. Scooba uses a special cleaning solution made by Clorox, which gives me a small amount of concern because I can't tell you if it would cause streaking or a dull residue over the finish of most wood floors. The other thing to pay attention here is that it suggests that any floor which you normally mop, a scooba will work for. With hardwood, you don't do traditional mopping, but think more like a swiffer here, very little liquid, just a light mist, then follow up with a micro fiber mop. Technically iRobot states that it is safe for sealed floors, which all prefinished floors are, but I would be cautious because I'm not sure how much liquid it uses and if too much gets into the seams it can spell disaster.

I think you would be a bit better off with something like the Roomba, using it solely to replace sweeping, then follow up with a proper hard surface floor cleaner like BonaKemi or one suggested by the floor's manufacturer and a microfiber mop.

Typically when cleaning wood or laminate floors you will want to regularly sweep the floor, or vacuum if your vacuum has an attachment without the beater bar, then follow up with a proper laminate floor cleaner and a microfiber mop. With the cleaner, less is more, use only enough to lightly mist a small area then follow up with the microfiber mop. Once done its a good idea to over the floor with a terrycloth towel or similar, on the end of your mop pole to pull up all remaining moisture, just to make sure it gets fully dry.

Q: I'm interested in putting laminate flooring in my family room but I have one problem. We have a limestone fireplace, and there is about a 2 inch variation at the bottom of it. So obviously I cant just lay the flooring up next to it. What would be some of my best options?

Chase G

Here is a picture of Chase's fireplace. You can see the variation he mentions from the different sized and shaped limestone pieces.

A: There are two options you can do here. If you are fairly handy with a jigsaw and scribing, then I would suggest scribing each plank to fit around the shape of the stones in the fireplace. This is a fairly common practice in commercial installations, fitting the planks to the stone. As long as the run from the fireplace to the wall on the other side of the room is not very long, you should have little problem with expansion, just leave a very small gap at the fireplace and a proper expansion gap at the opposite wall. This will require a bit more planning, but the benefit is that you are not affecting the stone of the fireplace, so if you change your floor the fireplace is untouched. Don't forget to use a silicone based caulking between the fireplace and the scribe. make sure it is silicone and not latex-based, especially if you choose a colored caulking, which tends to look better, as the latex based colored caulks can bleed color into the stone.

Although this method will take a bit of time, a couple of hours or so to scribe and cut all of the planks to fit the fireplace well, it will provide the optimal appearance and utility should you later decide to change out your floor.

Another option would be to treat the fireplace similar to a door jamb, and cut a relief into the stone so that the laminate can slide underneath with a hidden expansion gap. I will stress that I don't suggest this method as it will be messy and once done, changing floor coverings while keeping the fireplace looking good is tough.

To undercut the fireplace, you will want to use a pocket door saw with am abrasive blade, preferably a masonry blade or stone cutting blade. Measure for just a bit higher than the final height of the floor plus underlayment, scribe a line and then begin your cut work. While cutting, its a good idea to have someone there helping by having a shop vac on near the exit area of the saw so that all the dust that will be thrown out will get sucked up. Masonry cutting causes a lot of dust and unlike saw dust, it does not settle quite as quickly so without a good vacuum it will look like someone was blowing flower all over the place. Again, I stress that this is not the method I would suggest because it will permanently change the fireplace and cause quite a of a mess.

Posted by Bentley Pascoe on August 31, 2008 8:00 AM | Permalink

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