The Flooring Expert

Q: What is STC rating?

A: STC rating, or Sound Trasmission Class, refers to the amount of sound reduction a given floor has. This is typically a rating important to underlayments. STC rating is important to consider when installing laminate floors, as this can deaden the “clicking” or “hollow” sound laminate floors have when walking over them. This sound deadening can cause a laminate floor to sound closer to real floor wood floors. STC rating is also key to keep in mind for installing a floor in a condo or upper levels of a home. Home Owner's Associations tend to require higher STC rated underlayments, such as 6mm cork or Sound6 Barrier Acoustical underlayments, to prevent sound from transferring to other condos in a complex.

This testing is typically done in laboratories using a suspended ceiling which is insulated, a 6 inch thick concrete slab, the underlayment, and flooring. A machine is used to tap on the flooring at various frequencies tot est how much sound is lost when transferring from the room over the suspended ceiling to the room below

Q: What does 3-in-1 mean for Underlayments?

A: Underlayments which are labeled as “3-in-1” are a combination underlayment which consist of a foam underlayment, vapor barrier and seam tape. This type of underlayment is great for an easy all-in-one underlayment to go over concrete. The difference between underlayments labeled as “2-in-1” versus the 3-in-1 underlayments is that the 2-in-1 underlayment will not come with seam tape. This tape is required in order to seal the overlapping areas of the vapor barrier when installing over concrete. 3-in-1 underlayments are a great choice if you are looking to save a few bucks, but they rarely suppress sound as effectively as underlayments like cork or Sound6. If you're not worried about a laminate being a bit “clicky” or "hollow" sounding and you're working over concrete, such as in a basement, this is a great choice to make your job easier.

Q: Can you put a laminate floor over carpet?

Abohanna

A: This is a pretty common question. The answer is "no," but lets get into a deeper explanation of why. Although laminate is installed using the floating method, which allows the floor to be installed over the top of a subfloor without anchoring to the subfloor, carpet is not a suitable substrate. I have frequently had the question of "will carpet padding work as underlayment?" with customers who have called in to our call center here at iFLOOR. This is again an answer of "no." Due to how carpet and carpet padding are made, they are too soft to work as a suitable underlayment for floating floors. Simply put, they are not dense enough to fit floating installation specs.

End result, to install a beautiful new laminate floor into your home, you will need to remove the carpet, carpet padding and tack strip in order to get a clean subfloor, then you can install your underlayment (I'm a big fan of 3mm cork) and then install your laminate.

As a side note, there are a few hard surfaces you can install over using floating installations. Pre-existing hardwood floors, tile, vinyl and linoleum all can act as suitable substrates as long as you use a good underlayment (Sound 6 or cork being the preference here). In the case of tile, its suggested to level out the grout lines with the tile itself as best you can to ensure your floor will lie nice and flat and reduce possibility of issue.

Q: When installing floating Bamboo flooring over uneven concrete (Old tile mortar and slightly uneven) What would be the best material to use underneath?

A: When installing a floating floor over old tile or just remaining mortar, it is always suggested to make this floor as flat as possible. Now, if you still have the tile laid down and your worried about grout lines, you should have little issue as long as you use a vapor barrier and a good underlayment. I would suggest using 6mm cork or 3mm cork at a minimum.

If you have removed the tile and have only the mortar remaining you must grind this down. Similar to the discussion on removing thinset, Try using an electric chipper or a grinder. This will be dusty, so wear eye protection and a dust mask. Remember with any floor, it is important to have the subfloor clean, dry and flat.

After you have prepared your subfloor, I would still suggest using a 3mm cork underlayment for your floor. Cork is dense, so it will provide a better feel under foot, and its natural sound dampening and insulation qualities will be great. Good luck!

Q: Does the padding for floating floor have to lay on floor for 48 hrs before u can lay the laminate floors?

Margie

A: For floating floors there is no need to let the underlayment sit before installing the floor. However, it is important to know that after a floor is installed (and make sure to acclimate it before installing it) your floor will go through a secondary acclimation process as it adjusts to the area it has been installed in. So, you may want to let your newly installed floor sit for that 2 day period before placing furniture over it.

Enjoy your new floor and good luck with your install!

Q: Can I lay marble tile on a slate slab that is fairly flat?

Rick

A: You can install marble tile over a slate slab, but you will need to use an uncoupling product. Gene D., one of the guys here at iFLOOR.com that works with very large commercial jobs, suggested using the uncoupling products made by Ditra of Unimat. He specifically suggested Schluter®-DITRA. After that, just make sure you follow all instruction guidelines from the manufacturer and you should be ok. Good luck!

By request from a few co-workers, I'm going to put a brief summary here as to why you want to use an uncoupling product.

When using an uncoupling layer between a solid surface, such as slate or concrete, and the tile surface to be laid. This process has actually been done for thousands of years. The uncoupling layer neutralizes the differential movement stresses between the substrate and the tile. The rib structure of the uncoupling product allows for in-plane movement, which is why it neutralizes differential movement. These stresses when neutralized prevent what cause a majority of cracking and delamination in the tile surface.

Q: I would like to purchase the American Duet Vintage Pine Narrow by Armstrong but it doesn’t look like much padding on the underside.

Do I need more underneath the American Duet Vintage Pine Narrow by Armstrong?

A: The Armstrong flooring you're looking at from the Nature's Gallery collection does not include an attached underlayment – so you will need to purchase an underlayment to install this floor and maintain your warranty.

One of the cool features to this collection and the Vintage Pine you are looking at is that it comes in a wide and narrow format. This allows you to buy both widths and intermix them while installing your floor to give the appearance of a random width floor. This is a very popular approach which has been done by Virginia Vintage in a 3/5/7 format with their hand-scrapped engineered floors.

The benefit of not having a pre-attached underlayment is the flexibility to pick any underlayment of your choosing. Many customers will do this to use a more premium underlayment such as Cork or Sound 6, although this does involve spending a little more than with floors having pre-attached underlayments, you will usually get better performance from these floors.

Q: Our home has an old Saltillo tile floor…between the natural variation in the tile and the grout lines the surface is not terribly flat.

Thanks!
Bob Buddecke

A: Saltillo tile adds a level of difficulty to your project since true Saltillo tile is not uniform in dimensions. With the history behind how these tiles are made, every tile has slight variations in height, and dimensions, though some process recently has made them a bit more uniform.

In this case, it is not so much a matter of having thicker laminate as it is a matter of ensuring your get a good underlayment. With tile of any sort, the common suggestion/practice is to grind down the surface some, to get a flat subfloor. From here you will want to install your moisture barrier, then underlayment and flooring. In your case, a dense underlayment will perform better over the grout grooves and variations in the floor. Dense underlayments, such as cork, will prevent more movement in the floor then cheaper foam underlayments.

Having a thicker laminate will, in theory, give you a higher quality floor which can stand the test of time better, but will not directly account for the differences in the subfloor. Your installer's suggestion of finding a thicker floor is valid for durability reasons, but not to account for the subfloor. Any floor 10mm + in thickness should be good, although several manufacturers make very good 8.5mm or thicker floors that perform better than some thicker floors.

It is ok to install laminate over tile, assuming you take in certain precautions. Make sure you get the tile surface as flat and level as possible. Also, make sure you use a moisture barrier to be safe.

My suggestion would be to grind down the tile some, similar to grinding down a concrete subfloor to level it out in higher areas. Then look into a good underlayment, I would suggest 6mm cork. From there, find a floor you love and install it.

Q: Is a cork underlay needed if the cork floor, is going over a cement subfloor? We have turned a very large crawl space into 2 rooms and a bathroom and plan on putting floating cork flooring down (not in Bathroom), but are not sure if an underlay is needed, since sound proofing is not an issue. Is the additional insulation needed/worthwhile, since we live in Richmond Va. and it does not get that cold.

Thanks
Greg Lloyd

A: When installing a floating floor over concrete there are a few things to keep in mind. First of all you MUST have a vapor barrier. You will also want to ensure that your subfloor is flat and smooth. This could involve using a self leveling compound in areas where dips may have occurred over time.

The Cork you are looking at does have a cork backing, but I would highly suggest adding a 3mm cork underlayment to ensure you get maximum lifespan from your floor. You could use other underlayment types, but thicker underlayments (such as the 6mm Cork) would normally be used for added sound suppression, which your not focusing on here. Cheaper underlayment, such as the foam based combo underlayments are not as dense as Cork and will make the flooring feel springy under foot.

Q: I have been reading all of the information on laminates (absolutely the best and most concise ever) and will be ordering laminate for my upstairs tenant’s apartment. While picking the laminate is not such a problem thanks to your information, I am unsure of what is the best underlayment for me. You mentioned you liked cork, but when I looked at my choices there was a soundproof acoustical underlayment that said it was the best. Since these tenants are above my head I would like to minimize the amount of noise as much as possible. Your suggestions please.

Thank you,
Annette W.

A: When it comes to underlayment in apartment or condo style housing, the choices get narrowed a bit, but they become more difficult. The best underlayment for sound suppression would be Sound 6 Barrier Acoustical underlayment, but this does not mean it’s the best for your project. Aside from Sound 6 your best sound suppression will come from cork (6mm then 3mm respectively).

Nearly all HOAs for condos require cork as an underlayment for any wood floor to be installed. This statement alone shows the support for cork in such living environments, but I would suggest you look into the pros of each underlayment and make a choice as to which has the most benefit for your project.

Sound 6 has the highest STC (Sound Transmission Control) ratings of any underlayment out there at 73. It is made from a rubber/foam style material designed specifically to control sound transmission. The only downside you will encounter is that Sound 6 is not as dense as cork, meaning that it is going to break down a bit or "Sack out" as my good friend Gene D. likes to say. Also, since it is less dense, it will cause the floor to have a bit more spring to it (although this tends to be almost unnoticeable).

Cork offers great STC ratings 51 for 6mm cork. Cork's big benefit is its natural density and its memory feature. Like all cork products, cork underlayment will naturally attempt to return to its natural state, meaning it actively prevents itself from compacting over time. The density of cork also gives your floating floor a much more solid feel under foot. A few other great benefits of cork are that it is naturally hypo-allergenic and acts as a natural insulator.

In the end, I would tend to suggest 6mm cork, as it has become somewhat of a standard in Condos and apartments for its many properties, but I would not count Sound 6 out. I feel regardless of the choice you make, you will have an underlayment that will perform well. It becomes a question of additional sound control versus feel under foot and ability to withstand time.

Follow-Up: Annette has been working with James A. over in our sales team along with myself to get some additional help.

Q: Thank you both for your comments I really do appreciate it. With tenets above our heads I am looking for the quietest floor for the longest period of time I can. This may sound like and overdo question, but can I use a combination of the cork underlayment with the Sound 6, and if so is it overkill? Thanks again, I am looking forward to ordering my floors soon from a company that seems so responsive.

Annette

A: You could use both underlayments in theory, but in practice I would personally pick one underlayment and stick to it. I'm sure James would agree with me here that another option to look into would be to use 6mm cork and 3mm cork if you want to combine underlayments. The additional thickness of cork will provide more sound control while keeping to the better density cork offers. You can also get underlayments of cork up to 12mm in thickness through APC cork. One note I will give you is that the standards for public education facilities in the US show that the STC requirement near the loudest rooms (such as a music room) is 60. This is for STC ratings of walls, which means an STC rating of 50 or higher for a floor is very good.

My personal preference would be to use cork, but Sound 6 is optimal when it comes to suppressing sound and is far more durable than cheaper foam underlayments - so it should hold up just fine for several years. My suggestion would be to find out how much height you have to work with for an installation then maximize your underlayment while allowing the room for the floor.

Follow-up: I was forwarded a series of emails where Steve, iFLOOR's CEO, was helping advise a similar project on underlayment. Although I mentioned to Annette that I personally prefer to stick to one type of underlayment in a thicker amount, Steve gives some excellent advice.

I would use a 6mm cork first and then the Sound 6 Barrier. The key is the 6mm is comfortable, yet rigid and provides a great baseline for sound reduction.

The sound 6 barrier has INCREDIBLE sound reduction specs that can be found on the website. It is worth a few extra pennies to kick up your sound reduction to the low 70’s vs. quietwalk. (I have only limited experience with quietwalk and it was not all positive.)

Steve was asked: "a friend asked why cork first and then sound 6 on top, why not the other way around? Got me wondering – does it matter?" Here is where Steve's knowledge and years of experience yield great advice.

Yes – it matters – cork underlay is more stable than the sound 6 and should be the primary substrate. (if you need a moisture barrier use poly-ethylene under the cork – it is not relevant to the deflection and tensile strength discussion.)

At the end of the day it may not matter from a total components used point of view, however, the cork would be less stable over the sound 6 which would weaken the integrity of the floor above. My experience tells me that there is only one way to do it right.

Q: I am installing a Westhollow 12mm thick laminate floor…first time…I’m pretty comfortable with everything, but the underlayment…because it was 12mm, the folks at iFloor indicated the 3 in 1 would be okay for my install – it is on concrete slab and all downstairs. Here’s my confusion. The 3 in 1 has the words printed “this side up” on the plastic (moisture barrier side), meaning the foam is to the concrete. This seemed backwards to me as most guides I have seen indicate barrier, then foam. In a return visit, iFloor told me the manufacturer printed it on the wrong side and the plastic to the bottom.

Joe Connelly

A: This is a question that comes up fairly often and let me explain why it can be confusing. When you install underlayment like Cork or Sound 6 which is not a combination underlayment, you will install the moisture barrier, then the underlayment. In the case of combination underlayments you can install the underlayment with either way facing up, but here is why you are seeing "this side up" on the moisture barrier side.

The manufacturers of these types of combination underlayments will make their suggestion of which side should go up based on how they want the seams sealed. Also, one of the reasons why you will install with the plastic side up is that it is easier to install the flooring over the plastic than the foam. Gene D., our commercial contract manager, mentioned that this is similar to scrim on carpet padding or kraft paper and makes the installation much smoother.

In the end, it should matter very little which way you choose to install it; however, I would go the safe route and install based on the underlayment's manufacturer and put the moisture barrier face up.

Q: I am working on laying new 3/8" engineered wood flooring over a wood subfloor. I also have ceramic tile floors which will meet with the new wood floor and which are just under 3/4" higher than the existing subfloor. I am planning on adding another 1/4" (or maybe 3/8" if necessary) layer of plywood subfloor in order to help bring the wood level with the tile. At this point I have two questions: First, someone told me that when laying an additional layer of plywood subfloor that (at least in the case of vinyl) you should glue it rather than nail it since the nails can work up and out. Is that true for engineered wood floor also? Second, which kind of underlayment is best with a 3/8" engineered wood floor, the foam or the cork? My concern here is that while the foam may initially bring the wood up to the level of the tile it might eventually compress, while the 3mm cork would be less likely to compress to the point of being noticeable. The specific installation instructions do not make a recommendation.

Thanks for you help.

Sandra Romero

A: Nails can loosen over time. When nails loosen in your subfloor, more movement occurs and this is what causes most of the noise in a floor you might hear in a home. Usually to remedy this problem you would use a flooring screw to screw the plywood into the floor joists. This being said I would use screws rather than nails to add additional plywood to your subfloor. You could use an adhesive, but screws will be an easier and cheaper solution which should provide the exact same result.

In regards to underlayment I personally prefer cork because of its many natural benefits, density being one of the major factors. Foam underlayments, even the premium ones, have a bit more spring to them and thus will give your floor a bit more movement than something as dense as cork. In the end if you want the best feel under foot and will hold up the best over time would be cork.

Q: We are ready to buy an engineered wood floating floor, but have gotten stuck on an issue.

I have a single story house built in 1951 with slab radiant heat as the sole heat. Most of the house currently has glued down cork tiles about 4mm thick, the rest is carpet (which has been ripped out down to the slab) and peel and stick linoleum/?vinyl tiles. The system heats fine with this setup (old boiler in garage at 120deg F). We plan on installing a floating engineered oak floor. To keep the floor "sounding" the same throughout, I had planned on leaving the old cork tiles as an underlayment (adding vapor barrier on top), using a vapor barrier and adding 3mm cork underlayment in the exposed slab (where the carpet was) and putting a vapor barrier +/- 3mm cork or a combo underlayment on top of the vinyl tiles (a little worried about height differences).

Thanks,
Michael Jacobs

A: I have had many conversations about the impact of certain underlayments, specifically cork in most cases, on radiant heat flooring. A while back Steve mentioned to me a statistic I was unaware of: 3mm cork reduces the amount of heat generated by a radiant system by 3-5%.

Since you currently have a 4mm or so cork floor, you can expect the heat amount produced to be roughly the same. There will be a small difference which is insulated by the wood, by over all this should be a minimal difference.

For your tiled area, it may not be necessary to remove the vinyl, assuming it is in good condition, but if you have height worries, then I would remove the vinyl. Make sure you get all of the adhesive off of your subfloor before installing your vapor barrier and underlayment. I would shy away from foam based combination underlayments as they don't insulate sound very well and will put a bit more spring into your floor as you walk over it.

Overall I think you are headed in the right direction here. Just make sure you take your time during your installation and get everything right.

Q: I have installed several Pergo floors in the past using Pergo's SilentStep. I really liked the quietness of the floors with this underlayment. How does Sound 6 compare with it? I can find no information on the STC of SilentStep so I have no baseline to compare to. After reading Steve's blog, I noticed that cork is the highest recommended underlayment followed closely by Sound 6. The laminate flooring will be going in my kitchen area, so I'd like to go with cork for it's water resistance. Will I be giving up sound deadening over the Pergo SilentStep if I go this route. Should I layer 3mm of cork with Sound 6?

Thanks,
Kevin

A: Pergo SilentStep has a decent STC rating, around the same as 3mm cork so you won't be losing any sound deadening, especially if you decide to go with 6mm cork (you will actually gain a bit more). Most of the underlayment made by flooring manufacturers tends to be similar in quality, the highest STC ratings get around 3mm cork's quality, but no where near something like Sound 6. Although you lose some sound deadening choosing cork over Sound 6, you gain a bit from Cork's density and durability (not to mention the water resistance and hypoallergenic qualities).

If you primary concern is sound deadening, then you can layer cork and Sound 6, but make sure you lay down the cork as a substrate, then lay down the Sound 6. If you were to do this the other way, you would lose the benefit of cork's density since it would be riding on top of the Sound 6. If water resistance is a big factor for you, look into using 6mm cork to get a good underlayment with a high STC rating (around 55) .

Q: I am ready to purchase 10mm laminate flooring for my family room. I pulled the old carpet and noticed some of the subfloor joints were uneven. I made the repairs by screwing the joints down, however I still notice minor cupping and swells on the subfloor which I'm not sure how to level it out. Will the laminate floor be able to have some flexibility to the contour of the floor or do I need to replace the floor or add leveling compound? I was hoping to just install the laminate floor which comes with an attached underlayment and also add a 6mm cork underlayment as well for better sound and moisture barrier. Do you think this is overkill or can this be done? Your advise is much appreciated.

Thanks,
Anthony

A: There are a few major reasons why a wooden subfloor will cup or bow. First off, hopefully your subfloor is staggered at a 90 degree angle to the boards next to it. If your subfloor is rising up at the seams, then the problem here is most likely that there was not a relief left between each board to allow for some minimal movement. Typically this relief only needs to be about as wide as a paper match (or so) and if you are not seeing this relief, you can create one by taking a skill saw and cutting a relief. This will allow your floor to move and should relax the floor a bit. From here you will want to sand the floor down a little (assuming this is one you can sand such as plywood, but not OSB).

Now, if you are experiencing a cup between the joists and not just rising at the seams, then this is usually because of one of two reasons. Either your floor joists are spaced improperly (too wide) or the material used for your subfloor is not up to spec (cheap material not meant for being a 3/4" subfloor) and while the home was built most likely got wet and pressure from walking on it has caused the cupping. In this case, if the joists are improperly space you will need to get additional supports built in to account for this.

In the case where the material is bowing because it is not up to spec, you will want to replace this with new 3/4" plywood that fits spec for a subfloor. After you have installed the new subfloor you will be set to install your floor.

In regards to your underlayment question, using both 6mm cork and the pre-attached underlayment would not be over kill. With the pre-attached sitting over the cork (which will act as a subfloor) you should have a floor that is both quiet and feels very good under your feet. Now you could avoid using both and stick just to the 6mm cork with your floor once your subfloor is fixed, but again, both will not be over kill, just account for it when installing transitions and any other trim.

Q: I am a little confused about what type of underlayment I should purchase for the APC Athene Cork flooring I am purchasing. The floor I am installing the cork planks over is cement, about 3 feet above grade. I don’t think moisture will be an issue. Will a standard thin vapor barrier work fine? Are there any benefits to using the 3 in 1 stuff? Does the 3 in 1 also provide a vapor barrier? Thanks!

Sean

A: Any time you are installing over concrete moisture is technically an issue because concrete is a moisture based product by nature, but keep in mind that this moisture issue is easily resolved with a moisture barrier. In this case a 6mil polyethylene (standard thin moisture barrier for floating floors) will work fine. 3-in-1 underlayments include a moisture barrier by nature (moisture barrier, seam tape and underlayment are what make an underlayment 3-in-1), but keep in mind the only benefit to this type of underlayment is price. The foam padding itself is lower grade, typically breaking down much faster than other underlays and tends to leave a floor a bit more "springy."

With cork, I personally prefer using a further 3mm cork underlayment, this way you maintain cork's great density and still get all the necessary padding and some great sound deadening for your floating floor. Top this off with a 6mil poly vapor barrier and you should have the winning formula for a great floor.

Q: We are considering buying laminate flooring in our 11 year old house. Should we go with attached underlayment or not? Will we have to put down underlayment boards before we start?

Thank you

A: Depending on the laminate you are looking at buying and where you play to install this floor can give you a few reasons why to choose one underlayment over another. Laminates which feature an attached underlayment have a few benefits: price and faster installation. Typically laminate with pre-attached underlayment will be a bit more economical than buying laminate and underlayment separately, but usually this underlayment is a thinner foam underlayment which does not suppress sound quite as well as other premium underlayments like Cork and Sound 6.

If you are buying separate underlayment, you will not need any specific board to lay down the underlayment, but you will install it across your floor before installing the laminate. For foam based underlays, this simply means rolling out the underlay, then installing the floor. In the case of cork, cork comes in 2' x 3' tiles which you will lay out, then install the floor.

The decision of what underlayment choice to use is based solely on what performance you want from your floor. If you want a floor which sounds more solid and does not have the "clicky" or hollow sound most laminate produces when walked over, use a separate premium underlayment - I personally prefer cork because it walks very nicely. Also, if you want the floor to have a bit less spring or movement when walking over the floor, also look into non-attached premium underlayment.

If you are looking to save a bit of money and this floor is going to be installed in a room where noise is not an issue, then a floor with attached underlayment is a great choice.

Q: I am interested in using the Konecto vinyl planks in my kitchen/breakfast nook/den. Unfortunately the existing flooring is the old '70s style "brick" sheet vinyl. Pulling this up may run into an asbestos issue. I believe laying any "soft" product on top will eventually end up picking up the embossing. The research I've done indicates that an embossing leveler would be an option but as a DIYer I'd rather work with an underlayment (no mess, pet pawprints). What are your thoughts on using the Sound6 II as a base for the Konecto? What would be your alternate options?

Thanks so much for your help,
KG

A: Konecto specifically mentions to NOT use any type of soft underlayment or subflooring with their products. They do mention that you will need a leveling compound for things like highly embossed tile and to fill grout lines, but as long as these variations are not more than about 1/16" you should not need to worry.

If you are ultimately concerned with using an underlayment to account for the embossing, you would need to use something fairly dense. Cork could be an option, but I would contact Konecto directly to find out before purchasing any cork or proceeding with installation. The key here is not to ruin the inherent strength of Konecto's product and locking mechanism by installing it over an unsuitable surface.

Q: I would like to install a laminate (floating) floor in my basement, in a workout area (under a treadmill and a recumbent bike). My home is 17 years old, basement is dry and presently have carpeting; which I know I must remove with padding. Can laminate be installed under a treadmill? Could you recommend a particular brand? Also, should I use a particular vapor barrier/foam? Lastly, should I glue the laminate? If so, What type of glue should I use?

A: Floating floors can work with work out machines like treadmills. They can even work for something like a pool table assuming a few things are kept in mind. First of all, after you remove the existing carpet and pad, take your time to ensure the subfloor is as flat as possible. From here any 6mil poly vapor barrier will do, there is no need for a specific brand, but keep in mind this is a thin plastic (think like saran wrap for your floor) and not a foam, the foam is a type of underlayment.

The key here to making this floor suitable for your treadmill is a higher grade laminate with a dense underlayment, cork being your best bet. Underlayment is crucial because less dense underlayments, typically foam or rubber, leave a floor somewhat springy. Floating floors will naturally move ever so slightly under foot, but a dense underlayment, especially cork, removes nearly all of this movement and for heavier items, this is critical. Most underlayments act as a cushion where as cork does not give like the foams. Do not glue your laminate into place as modern laminates are not meant for this type of installation.

Product wise, avoid floors which have an attached underlayment and look into AC4 or AC5 rated floors. Thickness is not a major issue, though it can help here, but keep in mind a very good laminate like Quick Step Perspective (8.5mm) and Pergo Select (10mm) both perform very well, better than cheaper laminates of similar or greater thickness. Other good choices would include Westhollow's South Pacific or Handscraped lines.

Q: I am going to install a Pergo Vintage Home Traditional Strip floor in my dining room.
I am going to use 6MM cork as an underlayment. Does the cork underlayment also require a 1/4 inch expansion space around the perimeter of the room?

Thank you
Joe

A: If you wanted to be overly cautious you could include an expansion gap for the underlayment as well, but its not necessary. Cork is great in that it really does not expand/contract very much from temperature on its own and typically only sees much of this in the engineered floating plank versions of cork.

If you want to make the installation easy, just lay down your cork flush with the walls, then install the floor with proper expansion gaps and you should be all set.

Q: First, let me say thanks for hosting such an informative website about flooring, especially information about laminate flooring.

Blake
Killingly, CT

A: Each underlayment has its own specific R-value, but very few actually do a good job of insulating heat. Your best bet here will be cork as it is a natural insulator and the thicker the better. I would suggest using a 6mm cork underlayment as this will help to retain a bit more heat and keep the floor a bit warmer. You could also look into thicker cork, like the 12mm underlayments, but at this point you begin raising the floor a bit. The floor should stay right around the same temperature of the room itself using cork as an underlayment, but your hunch is correct - the floor will likely feel a bit colder.

If the temperature of the floor is a major concern, you could look into electric radiant heat pads to put under the floor between the floor and the underlayment. There are several great manufacturers of these items and they do an amazing job of keeping your floor warm without costing too much on the electric bill side.

Q: I've read through many of your answers regarding using cork as an underlayment for laminate for sound and even warmth.

I notice though that some of the products already come with "attached underlayment", for example ALLOC. Their video says that using other underlayments may cause the product not to work effectively and potentially void the warranty.

I guess my question is if you buy a product with the underlayment can you add another-for example the 3mm cork you mention to help with the warmth and sound or should you just stick to whatever their attached underlayment is?

Thanks!
Stacy

A: This can be a very trick endeavor. According to the Magnusson-Moss Warranty Act, as long as the underlayment you are using is of equal or better quality than the underlayment from the manufacturer then your warranty can not be voided because you used an underlayment not made by that manufacturer.

Assuming you were to use cork, which is a standard in the flooring industry as the premium underlayment, then you should not have this issue of warranty problems, but if you want to be safe I would suggest contacting Alloc directly. If they suggest one of their own products to go under the floor, then its a safe bet that cork will do the trick as well.

Q: I have a couple of questions, I would like to replace all my flooring (with the exception of the bathrooms) with durable, moisture resistant laminate flooring in maple. I'm confused as to what brand to use. I have vinyl in the kitchen and carpeting in the rest of my condo. The sub floor is 'soft' concrete.

Thank you.
Jeanette

A: Assuming that all of your current vinyl flooring is in good condition (not coming up or damaged) then you should be fine to install right over the top of it. Now if there are any problems in the current vinyl flooring, you will want to remove it. Typically removing it would then require removing the linoleum as well, but as I said, if the vinyl is in good shape and still well anchored, there is no need to remove it.

Now as far as laminate choices are concerned, there are several very good looking maple patterns out there, but you need to make sure the laminate you are looking at is both abrasion resistant and moisture resistant. Your best options here would be Westhollow's Eden Maple or Bird's Eye Maple from the True Natured collection, Costa Rican Maple from the South Pacific collection, Pergo's Milan Maple from the Select collection or the Nordic Maple from the Select Strip collection, or Quick Step's Maple Double Plank or Country Maple from the Eligna Collection. All of these are some of the better built laminates out there right now and have several very good patterns for maple flooring.

For underlayment, most HOA and Condo Associations are very stringent about what is necessary for sound suppression with hard surface flooring, especially wood floors. This being said, a majority of the previous condo installations I have worked with required no less than 6mm cork as an underlayment. The sound suppression statistics on 6mm cork combined with its natural density make it a long standing choice for any floating floor. Now if you want to go really over the top, you could use a 12mm cork underlayment or Sound 6 Barrier Acoustical underlayment over the top of a 3mm cork underlayment, but I highly doubt this would be necessary.

In the end your best bet is to put a high grade laminate over 6mm cork for your best flooring option in a condo, both as a matter of durability and suppressing sound.

Q: My wife and I are trying to figure out what we need to do to replace the flooring in our bedroom. A few years back we ripped out our old carpet and padding and the noise has visibly increased, as our living room is under our bedroom.

We are thinking about putting the Sound barrier II Acoustical Underlayment down plus the 5 Star Rate 6mm Cork Underlayment on top of the sound barrier.

Would this be a good idea? In addition, we do want to put some sort of finished floor down on top of all this. I like pre-finished hardwood floors while my wife likes cork.

The floor width that we have to work with is about 5/8". The square footage is about 250 square feet. The subfloor is plywood nailed onto wood joists. There is no insulation in the floor. Our walls and ceilings are sheet rock.

If you need further information, please e-mail me back.

Thanks for your help!
John Blackmore

A: When you remove carpet and padding it is very common to notice and increase in noise from the floor. Carpet padding has rather high STC/IIC ratings so it naturally reduces much of the impact.

In looking into a wood floor, there are some measure you can take to ensure much of the noise you are currently encountering is suppressed. My first suggest would be to take some flooring screws and ensure all of the plywood for your subfloor is not partially loose, which will make quite a bit of noise. Just put a few new screws through the plywood into the joists and you should eliminate a bit of noise.

After ensuring the subfloor is not loose, the biggest reduction in sound you will receive is a good underlayment. Your suggestion would eliminate a lot of noise, though I would suggest installing the cork first, to act as a substrate, then install the Sound 6 Barrier. this will help ensure you do not negate the benefit of cork's density. Now by doing this, you will take up about 3/8" just with your underlayment so I would honestly suggest just sticking with the cork as it should provide enough sound reduction on its own, similar to your old carpet pad. This will free up a bit of space for your floor since you are working with a height constraint.

As far as flooring is concerned, a floating engineered hardwood or floating cork will both work very well in this situation. You can also look into a laminate floor if you want to ensure your floor can take a bit more abuse.

If you go with a cork floor, you will have more sound benefit as cork floors naturally suppress a bit more of the noise you are currently dealing with. The downside to cork is that it is susceptible to gouging due to how soft cork is, but at the same time this makes cork more comfortable to walk on. Engineered hardwood floors will give you a bit more durability against gouges, but unlike cork dents will be permanent. In the end any floating floor will work for you and combined with the 6mm cork underlayment should give you plenty of sound reduction.

Q: The owner of the condo above mine has installed laminate flooring. He did so because of the amount of noise (loud talking, TV, and especially footsteps) coming through to our apt below with the vinyl flooring. He installed it himself. I know that the sub-floor is wood joists with 1 by 4 or 1 by 6 wood laid diagonally across the joists. There could be vinyl flooring over that. It is a 1965 building with no insulation between floors. It was intolerable before, but now, a new tenant who is up all hours of the day and night is making life a nightmare. Please give me a few solutions (medium to high cost) to help cut out as much noise as possible while still retaining the owners choice of laminate.

Rudy V.
Miami Beach

A: Condos typically have very stringent requirements for sound when it comes to flooring. The common "standard" in for North American condos is typically 6mm of cork underlayment, or the equivalent sound reduction of 6" of concrete.

Assuming you want to remove the current flooring, and install new underlayment, then reinstall the previous flooring, this can be done, and most likely would vastly improve sound absorption as the floor is likely installed over a cheaper foam underlayment. Another potential, though likely costly, resolution would be to install some sound board or similar sound insulation into the ceiling side of the subfloor between the joists.

Typically with a subfloor set up of this form, it is key to get good sound transmission control. Carpet is a good choice here as it is naturally great at removing sound transmission, but in the case of the laminate, installing 6mm of cork at a bare minimum would do quite a bit. You could go as far as to do 12mm of cork or 6mm of cork with a modified foam underlayment like Sound 6 Barrier, installed over it, then the flooring. These will run you around $2.00/sf, but the sound and impact control gained will remove a majority of the sound problems you are running into.

Q: Hi. I want to install laminate flooring in the basement of our house. Currently, there is carpet over concrete in the basement, but it looks old and I'm just ready for something new. We have never had any problems with moisture in the basement (our house is one a hill, so the back is above ground.) My question is about which laminate to choose, and how to go about installing it. We have 2 very active dogs, and they could potentially wreck a floor if it wasn't scratch resistant. Also, the basement is very cold compared to the rest of the house. Would using a cork underlayment help reduce this problem? Reducing noise isn't a concern for us, since it's in the basement, so I'm just wondering if it's worth it to use cork. (And if so, how thick?) MY choice for the floor would be something that comes in a very light color, since there is limited light down there.

Can you recommend something that would fit the bill?
Cortney

A: Of all wood floor types, laminate is by far the best suited to take abuse, but not all laminates are built equal. Before we dig too far into specific choices, let's first examine a base of what you should look for and go over some basic preventative things you can do to keep the new laminate you get in tip-top shape.

For the floor itself, you will want to look into commercial grade laminate floors. These floors typically carry an AC4 or AC5 rating. These floors have finishes and cores which are best suited for higher levels of traffic, potential moisture spills and similar damage possibilities. A few examples of floors to look into would be Quick Step Perspective, Pergo Select, Westhollow South Pacific or True Flooring Commercial.

For a few preventative measures, make sure you keep your dogs' nails clipped and trim back any longer fur which may cover the pads on their feet. This will help prevent your dogs from relying so much on their nails for traction and when they do use their nails, having them clipped will help keep them a bit duller - minimizing chances for damage.

As far as your underlayment is concerned, cork will provide an amount of insulation, helping to keep the floor's surface warmer. Cork also will help minimize the amount of spring the floor will have as you walk over it. This being said, 6mm cork is optimal if you want to get the best level of insulation for your floor, but 3mm is a good minimum to shoot for. Keep in mind that you must still use a moisture barrier between the concrete and underlayment.

Pattern wise, look into lighter oaks or maples as these are more likely to give you the color you are shooting for in your basement. You can also look into Beech or American Cherry patterns, as these fit the lighter tones you are shooting for.

Q: I purchased 3" wide 5/16" T&G engineered flooring to be installed floating on a cement pad. I also purchased sound 6 barrier II and Poly vapor barrier. A professional installer suggested that I will not be satisfied with the sound barrier I purchased because I will still have sound. He didn't suggest anything particular to use. Can you give me advise? I have read a lot of the suggestions you have provided to other customers and it seems that cork underlayment might be a better way to go.

Thanks for your help.
Terry

A: The combination underlayments, such as 2-in-1 and 3-in-1 feature a very thin foam underlayment which is nowhere near as dense nor sound dampening as Sound 6. Plain and simple, combination underlayments are cheap, great from an economical stand point, but from a perspective of giving your floor a good sound and feel under foot they are nothing when compared to cork or a well design modified, closed cell underlayment like Sound 6.

Sound 6 features the some of best STC and IIC ratings in the industry and no combination underlayment can hold a candle to it. STC ratings for your typical combination underlayment is usually in the mid to high 20s where as Sound 6 has an amazing STC rating of 73 (that's more than 6" of concrete in equivalence).

Sound 6 is a great underlayment, but you may feel some movement depending on the amount of traffic on the floor or the weight distribution over the floor. Now if you feel movement it will be very slight and not really "spongy," but if you really want to ensure your floor feels solid under foot then you may want

Q: I currently live in a condo and my upstairs neighbor wants to install a wood or laminate floor. They currently have the builder supplied carpet and underlayment. While we can't hear them talking, we can definitely hear them walking and other thumping noises from above. We are reluctant to give permission for them to install new flooring since we feel the noise might increase. Is there a solution to letting them install wood/laminate flooring and reduce to noise we hear now? Is cork underlayment the solution?

thanks,
Warren

A: There are two very important factors to noise transmitting from an overhead floor, STC and IIC. Now let's break down these terms, STC or Sound Transmission Control, is a measurement of how much sound transfers through the floor. IIC or Impact Isolation Control measures how well something absorbs impact. When combined, these two ratings will give you an idea of how much noise you will hear from ambient sound, like talking, and impact, such as walking.

Finding carpet statistics is very hard, but roughly put your average carpet pad and carpet will give you an STC rating around 55-60 with IIC ratings around 75. Carpet is the king of impact control, which is why it is so commonly used in apartments (it can also be very cheap). With 6mm cork you will have STC ratings of 51 and IIC ratings of 50 - so you have similar sound control, but much less impact control. Now the other typical underlayment option that you can look into is something like Sound 6, which will give you STC ratings of 73 and IIC ratings of 61-63.

This leaves a fairly tricky scenario, but a solution that has been recommended in the past is to use 6mm cork as a substrate and then put Sound 6 over it. This combines all of the benefits of both, which when combined should give you the best solution for getting a hardwood floor to perform at the levels of carpet. Keep in mind that regardless, this will still be a hard surface floor, and some noise will change, but with this underlayment set up over a solid floor (might want to avoid some of the cheaper laminate floors), you should be able to satisfy both your wants for sound suppression and your neighbor's want to have a wood floor.

Q: I am going to install a 12mm laminate over new concrete slab. The slab has some imperfections, notably some uneveness, noticeable only when laying a long straight edge on the floor, also some roughness. The installer swears he has used a 1/4" thick 2-in-1 underlayment in the past, claims it was from Pergo, and if that is used the resulting floor will be perfect.

Are there any underlayments 1/4" thick?

A: I can't say that I know of a 1/4" underlayment made by Pergo, but 6mm cork is roughly 1/4" thick, so there are some underlayments out there which are 1/4" thick, but aside from carpet padding or cork I can't think of any wood flooring underlayment that is a foam type or oil-based (like Pergo's) which is that thick.

Regardless, your subfloor should be leveled out if there are variations in height of more than 1/32". You could go as far as 1/16", but even then its best to level out the subfloor to ensure that you get a floor which not only sounds and feels great, but will stay that way for a long time with proper maintenance.