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: What is hardness?

A: Hardness ratings for hardwood floors vary from country to country, but the most common test is known as Janka Hardness Rating. This test measures the force required to push a steel ball into the wood up to half the diameter of the ball. This ball is 11.28 millimeters, meaning the force measured is to push this ball 5.64 millimeters into the wood. Essentially this measures a wood's density and thus its dent resistance. White oak which is one of the most common woods used in flooring has a hardness of 1360 on the Janka scale.

A good way to gauge the dent resistance of a wood is to determine how it rates when compared to white oak. If the floor is much harder than white oak, such as Brazilian Walnut (also called Ipe) which rates at an amazing 3680 is far more dent resistant than white oak, where American cherry rates at 950, making it softer than white oak and more likely to dent.

To sum this up, hardness rating gauges the dent resistance of a wood floor. when looking at wood floors, if your worried about the floor being dented by foot traffic, find a floor with a higher hardness rating.

Q: What is meant when someone says "re-screen a floor?"

A: This goes back somewhat to our question from Lucy about her cork flooring. Re-screening a floor is a way to refinish a floor without actually sanding off any of the wood surface. This is typically used with bamboo or cork flooring to refresh the finish on a floor, removing the appearance of scratches or scuffs.

To screen a floor, you must keep in mind a few things. First this will more than likely void any warranty you have on your floor's finish, so always consult your floor's manufacturer before doing a re-screen. Secondly, I highly suggest consulting a professional floor re-finisher as this is a tedious task and it requires very exacting methods to ensure no issues occur with the new finish (such as bubbling, flaking or blotchy spots).

You will start by ensuring the floor is clean, then using a buffer or sanding block and a high grit screen/sand paper (usually 200 to 400 grit) or you can use a maroon pad (320 grit equivalent), you will lightly rough up or buff the surface of the floor. The key here is light buffing to prevent the appearance of swirl marks. If you are going to use a machine to buff, ensure this is a polisher built to remove less finish. If this is done by hand, the block you are using (typically a mop head and pole configuration similar to the ones used to clean floors) the weight of the block alone should be enough to buff the surface so there is no need to apply additional pressure. This will allow a new layer of finish to properly adhere to the floor.

Then, using a proper finish that suits your desires and your floor, apply the finish. The rule here is to keep the coats thin to allow for even distribution. It is better to use many thin coats rather than thicker coats. Always ensure to follow the instructions provided by the finish manufacturer. Normally you will want to apply 2 - 3 coats when doing a full re-screen, but make sure to buff before laying each new coat of finish. Always allow proper time to dry and ensure the temperature in your home is not too high. When finish layers dry too quickly, they will cause fish eye shaped bubbles or begin to flake off because they do not adhere properly.

Remember, always consult your floor's manufacturer first for recommendations and exclusions and follow all instructions to apply new layers of finish.

Q: We are going to replace the flooring in our condo apartment in the near future. A floating cork floor system is our preferred choice but the condo's rules are that carpet over padding must be installed for sound transmission suppression to adjoining units. However, they are not specific about what kind of carpet and underlayment must be used. I can't help but think there are some lower quality carpet and underlayment systems out there that are no better or even worse in control sound transmission than a high quality floating cork floor system .

Phil S.

A: Much like wood flooring, the amount of sound reduction garnered from your carpet will be based on the carpet and more importantly, the underlayment you use. Carpet's big benefit is its impact insolation class (IIC rating). I'll be honest, I had to spend a bit of time searching for some good info for you, as finding carpet's STC ratings can be difficult. Basic information I could find was that 40 oz. Carpet with padding would give around a 55 or so on the STC ratings. This however is heavily dependent on what underlayment is used for carpet, and the ratings I found were using basic pad and no special underlayment. What I would like to use is a link to the minimum STC ratings required for public education buildings.

As you can see, beside louder rooms (i.e. A music room) STC ratings of 60 are required. Cork, being a natural insulator, gets great STC and IIC ratings. Most HOAs (Home Owners Association) require the use of cork underlayment when installing a wood floor. The 6mm 5-star cork underlayment we carry has an IIC rating of 50 and an STC rating of 51 in lab tests. This does not include what you get from your floor.

In this case, I would honestly suggest presenting the STC ratings for 6mm cork.

Then compare these ratings to the national standards for public education and it should give your board an idea of how much reduction you can get just from this underlayment, not to mention the cork floor.

End result here, install a good floating cork such as Westhollow or APC, over a 6mm cork underlayment and this should fit the ticket.

Q: I want to put wood flooring in my walk-out basement. Since it is below grade, I understand that I need to use an engineered wood floor.

Thank you.
Kathryn

A: VOC content in adhesives is heavily based on manufacturer, as each engineered floor uses a different adhesive. Your best bet to find a floor which is easier for you when it comes to VOC content is to research the emission ratings of the floors you are interested in. Look for E0 or E1 as these are the two lowest ratings. You may have to contact manufacturers directly to get this information as it can be difficult to find at times.

However, I do have a bit of information that will help make this much easier. Look into a 5/16” solid hardwood. Due to the design of these floors, they are stable enough to be installed over concrete and below grade. With the 5/16” solid you will only encounter the glue used to adhere the floor to your subfloor and none in the product. Westhollow carries a great 5/16” collection.

Follow-up: Kathryn and I have spoken a bit more on her project. Looking into both 5/16" solid and laminate as possible choices for her floor. Here's a follow-up email I received:

Thank you for referring me to the Westhollow products. I did look at the 5/16" solids and they are beautiful. And, there is a store in Melbourne, FL so I can look at the actual products.

** I do have a question about the Westhollow laminates. Do these have a E0 or E1 rating? I read the descriptions and noticed that they were made with a high density fiberboard (wood shavings and resins). My guess is that these would probably off-gas. Do you have any information? **

From a website called, GreenGuard.com, I got the names of two manufacturers who are certified to have low/zero emission laminates. They are DuPont and Wilsonart. I also learned that EcoTimber produces a low emission engineered wood floor.

Thanks again and I look forward to your response.

A: As I recall off hand all Westhollow products are E0 or E1 rated, but I'll get in touch with Ryan W., who is our product guru here just to make sure. Wilsonart has always made great products, but to get the really good laminate they make you do shell out a few extra bucks.

One thing to keep in mind with Laminate is to have a good underlayment to remove the hollow or "clicky" noise these floors produce when they are walked over. Although there is some resin used to create the high-density fiberboards, they are super durable floors. We recently did some Tabar testing on several floors for Westhollow as we wanted to compare solid and engineered hardwoods against bamboo and laminate floors to get some ideas of where each floor will perform.

No surprises showed laminate to be the top dog when it comes to abrasion, durability, dent resistance and even moisture resistance. However, the engineered hardwoods performed very well, getting rather close to laminate in each test.

The one benefit to the 5/16" solid I suggested is they perform well like an engineered will for durability, but they are a solid hardwood so they add great value to your home. However, if durability is your large concern, laminate and engineered woods will be your better bet. I'll shoot a quick email over to Ryan and get back to you with the emission ratings for the Westhollow products. Have a good one!

As a bit of follow-up Ryan W. let me know that all of Westhollow's newer laminate collections were tested to be E1 on the emission standards, perfect for folks with a chemical sensitivity. This includes the Heritage Standard, Silencer American Traditions and Silencer Exotic Antiquities.

Q: I am looking at maple hard wood flooring from RONA. They have a wonderful deal on at the moment, about 3 Canadian dollars a sq foot. It looks wonderful, the manufacturer is Foresta. I asked what I should put under the floor before laying onto a wood sub floor. They said I should put nothing down except if I wished to use a resin paper? What is this resin paper? Also they explained I would nail it down with the proper nails and use a nail gun. What do you think of the information I have given you, does it sound fair? Do you know Foresta flooring?

Regards, Jason

A: For your first question about resin paper. This is a paper used to make it easier to slide boards into place and to reduce the potential for creaking noise made when walking over a hardwood floor. This paper is also referred to as Kraft paper or 15lbs. Roofers felt. In some cases you may wish to use a heavier paper, as this can help reduce a bit more noise potential, but it is not necessary.

I would suggest using the paper, as most professional installers will always use a paper before installing a nail or staple down floor.

In regards to Foresta, I will admit I don't know them very well. For Canadian flooring producers the major manufacturer I know is Preverco. Preverco makes some excellent flooring at good prices.

Q: I searched your entire site but cannot find the answer to this question...Why the different thicknesses of the products and how do I know what thickness of (say, a laminate or bamboo) to buy?

K

A: Products are made in various thicknesses for different reasons. It is heavily dependent on the product itself. For bamboo and laminate, the rule of thumb tends to be that thinner products are of lower quality. Many 7mm laminates are great economical choices, but they don't stand the test of time of something over 10mm. In the case of bamboo, solid bamboo is normally 5/8” thick and anything thinner is normally cheaply made product, so beware.

Hardwood is where things get a bit more technical. For solid hardwood the standard is 3/4”. Another important thickness is 5/16” and although it is much thinner than 3/4” it is more stable and able to be glued down to a concrete subfloor unlike 3/4” solids.

For Engineered floors, thicker floors tend to have more plies and a thicker species layer. Some manufacturers will use less plies, but use higher quality substrate with each ply being thicker than less expensive floors with more plies. In the end, the rule here is the more plies the better and a thicker species layer will be your best bet.

So to sum it up, thinner laminate and bamboo tends to be a bit more economical and lesser quality. For solid hardwood a thinner solid has more stability and can be installed in areas a normal 3/4” solid can't. For engineered floors, try to find a floor with more plies and a thicker species layer.

Q: I am interested in ordering Kahr's Linnea 2 strip life - Maple. I'm wondering whether this is city or country grade?

R.K.

A: When you say "City" grade I'm curious if you mean select, select and better or clear grades. City is not a common grading term I personally am familiar with; however, to my knowledge the veneer layer of Kahrs' linea is a more uniform appearance common in clear or select and better graded maple. My guess is this is what you mean by a city grade, where you see less character and grain variation that is visible in common and country grades.

Keep in mind that this is a wood veneer, meaning the species layer of the flooring is close to paper thin. In this case, this is closer to a laminate for the considerations of refinishing as it can not be refinished.

Follow-Up: If you visit Kahrs' website they label 3 grades for Linnea: City, Town and Country. City/Town/Country looks to be simply the naming convention Kahrs is using to make it simple and easy for branding purposes. My guess without doing several phone calls is that Kahrs’ “city” grade is mostly clear grade Maple. Clear grade (this is from the National Maple Flooring Manufacturer’s Association standards) is the most monochromatic and uniform grade of flooring.

Q: What is OSB?

Eric

A: OSB stands for Oriented Strand Board. OSB evolved from Waferboard and is an engineered wood product formed by layering strands (flakes) of wood in specific orientations. In appearance it has a rough and variegated surface with the individual strips (around 2.5 by 15 cm or about 1 inch by 6 inches each) lying unevenly across each other in the direction of their grain.

It is manufactured in wide mats from cross-oriented layers of thin, rectangular wooden strips compressed and bonded together with wax and resin adhesives (95% wood, 5% wax and resin). The layers are created by shredding the wood into strips, these are sifted and then oriented on a belt or wire cauls. The mat is made in a forming line, the layers are built up with the external layers aligned in the panel direction and internal layers cross-oriented. This cross-orientation (similar to cross-play lamination used in making engineered hardwood) gives the board strength while also reducing the expansion and contraction that can occur from temperature change.

The sheet is then put through a thermal press to compress and cure the resin coating the flakes of wood, which causes the entire sheet to laminate together. Most of the worlds OSB is made in the USA and Canada in large production facilities. The largest production facilities can make over 1,000,000,000 square feet of OSB per year.

The difference between OSB and Plywood is fairly simple. Plywood is made of sheets of this wood laminated together rather than many flakes of wood. Both plywood and OSB are great subfloors for nail or staple down installations, but you should NOT glue down a floor to OSB.

Here is a great picture of what OSB looks like as it is being prepared for lamination.

Q: I have installed the 3" Bubinga Deep Cognac Westhollow® Wood 3/8" Engineered. I wanted to know if I could put a coat of wood floor polyurethane on them? I like for them to be real shiny and not to get damaged. I feel if I put the polyurethane on them they will be less likely to damage if something is dropped on them.

Thank you
Mona Clark

A: Adding additional Polyurethane finish (which is your common finish on most wood floors) can add some additional protection and if you use a higher gloss finish, a bit more shine, but keep in mind that with pre-finished floors, once you add more finish, the initial warranty on the floor is usually voided.

Let's do a bit of background here about floor finish and the pros and cons of refinishing or adding more finish to a floor.

The level of gloss or matte to a floors finish is a key indicator to one thing. Typically, floors which are matter or low gloss carry more aluminum oxide (or similar protective agents) which help prevent scratching and abrasion on your floor. High gloss floors (which have a great shine) have less of these particulates in them, meaning that they are more susceptible to to damage from abrasion (scratches typically). The key lesson to learn here is that by adding higher gloss finish to a floor, you gain minimal protection when compared to the matte finishes which contain higher amounts of aluminum oxide and similar protective additives.

So this might leave you with the question "What is Aluminum Oxide?" Good question! Aluminum oxide is one of the toughest substances on Earth, and it has been added to flooring finishes to give additional protection. If you were to look at a wood floor through a high powered microscope, you would see a jagged surface where the finish containing aluminum oxide is. The jagged portion is the aluminum oxide particulates, which act as a barrier, causing items which run over the floor (such as grit, pet nails, etc) to hit the aluminum oxide and not touch the actual flooring itself. Pretty handy for keeping a floor looking tip-top.

Finish typically protects against abrasion and is not as pivotal in preventing denting (such as dropping a soup can on your floor would cause). A floor will get damaged in this manner over time, no floor is bullet proof so to speak, but certain floors are less likely to dent. Floors which feature a species with a higher Janka hardness rating are less likely to dent. Also, for engineered floors, the more plies and the higher quality the plies are, the more dent resistance you gain from the floor.

Now, with that information about floor finishes in mind, let's talk pros and cons with adding finish or refinishing a pre-finished floor. The biggest con is that as soon as you alter the finish on a pre-finished floor, its warranty is normally voided. The benefit here is that you can add further layers of protection against scratching based abrasion or add a bit of gloss to your floor.

If you decide you want a higher gloss level on your floor or additional protection, you will have to go through a process. First of all, you will need to lightly rough up (or buff) the current top layer of finish. This will allow the next layer of finish to properly adhere to the previous layer. You will then apply a thin, even coat of finish and allow it to cure. Repeat this process as many times as desired, then give the new finish plenty of time to fully cure before having much traffic over the floor or moving furniture back into the room. Typically it is best to have a professional do this process as it can be painstaking, and small mistakes can cause problems in the finish, which will require removing all of the new finish and re-applying it.

If your primary concern is damage from dropped items or getting dents of some form, adding more finish won't give you much protection in this area. It will give you some, but not very much; however, you can add some shine if you want a floor with a bit more gloss. One tip I have to prevent denting in your floor, beyond being careful when carrying things, would be to not wear high healed shoes on your floor. An average person weighing 125lbs. wearing stiletto high heels exerts about 2,000lbs. or pressure per square inch which can put a dent in the toughest floors.

Q: How do you figure out how much square footage of flooring you need to cover a room? My room measures 15.4 x 11. Which I was told was a little over 165 sq ft. How much flooring will I need to order? I'm using Pergo Acculade tiles 16".
I've already ordered 9 cartons and want to be sure that that will be enough.

Thank you
Liz

A: For flooring you will multiply the length and width of the room, then add 10%. So you should need roughly 186sf or as close as you can get to this number by cartons. 9 cartons should put you just over 180 sf, which should be enough, but let me explain why you add the 10%.

When you are installing flooring, you will have to do some cutting and you will have some waste. Typically when you add 10% to the exact square footage of your room (which is about 169sf in this case), you should have enough to ensure that you can cover all of your cuts and waste. Typically flooring manufacturers will have up to 5% of their product as unusable, which is the accepted standard in flooring. The extra 5% of our 10% account for cuts assuming you have maximum unusable product, but rarely is this the case.

Take your time, measure twice before you cut once and you should be fine.

I got this question from a comment on our video How to Install Westhollow Laminate Flooring on YouTube. Check it out if you get a chance as its a great guide for installing any laminate.

Q: What is the difference with laminate and wood?
Thanks

A: We'll first assume that by wood we are talking about traditional hardwood flooring. The major difference is that hardwood is made from sawn planks of timber whereas laminate is a picture of wood laminated through heat and pressure to adhere it to a core board and backing. Basically put laminate is an engineered product constructed using a medium or high-density fiberboard (a wood product) which is then laminated together with a backing board and a surface layer which is composed of an image (photograph of a wood pattern) and an extremely tough-wearing aluminum oxide. Hardwood flooring is made from sawn timber which is then milled and finished to create plank of finished wood flooring. The major difference is that hardwood is made from sawn planks of timber whereas laminate is a picture of wood laminated through heat and pressure to adhere it to a core board and backing.

Here's a great overview of what Laminate is from Steve's article Laminate Basics:

Though laminate flooring was introduced in the United States in 1996, it has been sold successfully in Europe for about 20 years.

Most people have never heard of laminate flooring and have no idea what it is. But chances are, those same people know what Pergo flooring is. Well, Pergo is laminate flooring. They were the company that first created this type of flooring, and was the first brand of laminate offered in the United States. For this reason, its name has become synonymous with laminate flooring despite the presence of about 40 other brands.

Essentially all laminates are composed of three layers.

The Surface Wear Layer

The surface layer is typically made of an extremely tough-wearing aluminum oxide. The pattern that you see as you look at the floor is actually that of a printed photograph adhered to the clear surface. Many people consider the pattern an additional layer, but for simplification, we consider them as one. Many laminates look like wood floors, but it’s merely a photograph of a wood floor applied to a melamine laminate. Because you can photograph nearly anything for a floor, there are few limitations. Most, though, are wood-, stone-, brick- and tile-based.

The Core

The core board or “carrier board” is made up of a variety of materials, depending on the manufacturer. Most manufactuers use HDF, or high density fiberboard, which is a durable engineered wood product that resists moisture. Others can have a high-density wood particle core. While the HDF may be slightly more structurally sound, the particle core absorbs glue slightly better at the joints. Both materials, if manufactured by dependable companies, provide a durable, trustworthy core.

Backing

The backing board varies depending on who makes the floor, but it ranges from a paper layer to a full plastic laminate layer. Those with a laminate or melamine backing may be better against potential water damage than those with paper backings, and the laminate is more stable.

All of these layers are fused by heat and pressure either by direct-pressure or high-pressure construction. A direct-pressure laminate (DPL) is assembled at once, then heated and pressed to form a bond. High-pressure laminate (HPL), on the other hand, involves treating the top and bottom layers separately and then fusing them to the core layer under extreme pressure. HPL is a more recent innovation and is often found in the more expensive premium brands

Q: What is the difference between Acrylic and Urethane finishes?

- Rob

A: The technical definition here is that urethanes, scientifically known as carbamates, are organic compounds which come from carbamic acid. Acrylics are similarly organic compounds; however, they are derived from acrylic acid. Basically speaking it a is a differences between the base acid of which the compound is derived.

When it comes to flooring the important difference is usually acrylic impregnated versus urethane finishes. Urethane finishes are applied to the top of a product in several thin layers. These urethanes are modified in various ways depending on the desired look of the finish and product it will go over. Most commonly, water-based urethanes are used for flooring; however, in some cases acrylic-urethanes are used.

Acrylic impregnated floors have moisture vacuumed out of the wood through a high-pressure technique. Then liquid acrylics are injected into the open pores throughout the depth of the hardwood. Optionally, stain and fire retardants are added in with the acrylic. The acrylic resin makes it up to 300% harder and more dent resistant than natural wood.

Although acrylic impregnated floors are tough, they are also virtually impossible to refinish properly, meaning that once your finish gets to a point of where you would wish to have it sanded down and redone, you would instead have to replace the floor.

Cork flooring typically has a water-based acrylic. Basically instead of the urethane in the floor you are using acrylic instead. Essentially speaking you are using plastic to protect the floor. Acrylic, in the plastics/glass industry and similarly in flooring, is a durable and roughly 93% translucent product which is featured to give abrasion resistance to floors, much as urethane finishes do. The difference is entirely in the derivative acid.

Q: I have an upstairs condo where I want to replace my carpet with a cork floor. The HOA requires a minimum IIC of 50 for a new floor. The existing floor is has a 5/8 sheet rock ceiling below, 2x12 floor joists, a 3/4 plywood subfloor with 3/4 in gypcrete over that. I plan to put a layer of sound barrier 6, a 1/4 in cork underlayment and your Westhollow cork plank. Will this assembly have a rating of 50 of more? Can you send me your opinion on this that I can send to the HOA?

Regards
Tom McCall

A: Condos have very stringent requirements when it comes to installing wood flooring, but with some careful planning it is very easy to surpass these requirements. With the subfloor assembly you describe and using the particular underlayment and flooring you wish to use you should easily pass the IIC/STC rating of 50 required by your HOA, but let's dig into a bit of detail on this.

Based on the items you intend to use, I would suggest the following installation set up. Lay down the 1/4" cork underlayment over your subfloor as a substrate. This will help maintain a bit of the density benefits the cork provides a long with acting as a final line of defense for sound and impact insulation. Now the 5-star rated 6mm cork (just shy of 1/4") that we carry has a relative IIC rating 55, which means it alone passes the test you have ahead of you. You can expect similar results from other 6mm corks, but let's drop it down a bit and guess that you will get right on the 50 you are after (most tested scored 53 or 54).

After you have installed the cork, lay the Sound 6 Barrier underlayment over the top. This will act as your initial sound and impact insulation. By having the Sound 6 installed over the cork this prevents the cork underlayment from moving as much (as it would if installed over the sound 6) and maintains a bit less spring in the floor as you walk over it. Sound 6 has an IIC rating of 71, so when you combine that with the 1/4" cork you should be well over the 50 IIC rating you require. Keep in mind, cork flooring in itself reduces some impact and sound as the top layer of each plank is just over 3mm of cork.

Combined here you should have a 50 IIC at a very minimum and should easily meet your HOA's needs.

Q: What is the difference between flush stair nose and overlapping stair nose? What are the advantages/disadvantages of each?

Berta R.
Tucson, AZ

A: Based on the type of nosing you choose will determine the look and utility of your installation for your stairs. Flush nosing will tend to have a more professional or custom look, as the molding and planks of flooring sit evenly. Although this tends to look better, the downside is that you have a bit less expansion gap potential, so you should leave a bit more room underneath the riser for expansion.

Overlap nosing will have the visible appearance of the overlap, but you get a bit more leniency with your expansion gap, as you can lean a small gap under the overlap and the remainder of your gap under the riser. Also, unlike a flush nosing, you can typically match an overlap nosing of proper height up to any floor, regardless of joint, whereas the flush nosing requires the same joint; for laminate you would want a flush nosing with the exact same locking mechanism, typically from the same line of flooring matched to the floor.

Q: What is the significance/meaning of the the term "Builder" Bamboo? Thanks.

A: Basically put "builder" grades are commonly made of a mix of grade A and B bamboo. This means it tends to be slightly less expensive, but it is very rare to visibly see most of the differences in the bamboo because of how bamboo is made and looks.

Differences in grade:

Grade "A"
Relatively free of markings, considered to be the "cleanest" and most desired quality of bamboo flooring.

Grade "B"
Very subtle flaws in the plank surface but still maintain even coating on plank surface. Grade B bamboo may contain small splits or cracks on the tongues portion of the plank.

Typically, builder bamboo is just a good way to save some money, I can't say that I have seen any "builder" bamboo which is not still of great quality and will not lay as a good floor.

For our August edition editorial here on the Ask the Expert blog, I wanted to break down and discuss AC ratings for laminate floors. AC or Abrasion Class ratings are a way for folks to determine cost versus durability of laminate floors.

So, before we determine what each rating means, let's know what the AC rating tests. The abrasion testing done ranges from resistance to burning, scratching, impact, chair casters, furniture legs and more. Basically any type of common abuse the laminate floor would see in a variety of applications from basic homes to commercial applications. Once all of the data is compiled, each line of laminate is assigned a rating of 1 through 5.

AC1 - the lowest tier of laminate floors, these floors are built to resist minimal residential traffic and are typically very inexpensive. AC1 laminate flooring is suitable for low traffic rooms such as bedrooms or other rooms in a home where traffic is light.

AC2 - suitable for lower traffic residential areas such as living and dining rooms. These areas receive some traffic in a home, but are not the rooms which will see the most abuse.

AC3 - these floors can be applied to a more varied area such has small offices, kitchens, recreation rooms or even very light commercial settings such as small office buildings. These floors are also much better at resisting the scratches from pets due to their stronger finishes.

AC4 - built for light to medium commercial applications, these floors are the beginning of commercial grade laminate. Suitable for busier offices, boutiques, restaurants and similar locations, these floors also are great in homes with multiple pets or children.

AC5 - the highest tier of laminate, these floors are suited for higher traffic commercial applications such as department stores, hotels, public buildings and similar areas where much higher amounts of traffic move through. These also see some residential applications for people who want the highest quality laminate floors or wish to ensure they have a floor which is as abuse resistant as possible.

Most quality laminate these days is typically at least AC3, and very few floors below this rating resist common abrasion very well and usually require fairly stringent cleaning schedules to ensure minimal abrasion possibility. I tend to recommend AC3 rated laminate at a very minimum simply from a durability stand point, but some times it necessary to get a laminate floor which is more budget friendly. Often, laminate is far more abrasion resistant than other forms of wood flooring, but keep in mind that the highest quality finishes applied to some hardwood floors will perform akin to AC3 and AC4 laminate - so not all laminate is tougher than traditional hardwood floors.

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.