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Healthy Home Basics - Interior Floors

By HHI Staff

From The Healthy House Answer Book: Answers to the 133 most commonly asked questions. Questions 99-110.


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99. Why don’t you like certain types of carpeting?


Some carpets are high emitters of VOCs. Choose low-VOC types.


100. What’s the best kind of carpet to buy?


Look for those rated by the Carpet and Rug Institute's Green Label Program. Otherwise, the best advice we can give is to look for a product with as little odor as possible. It’ll help to take someone along with you who has a good sense of smell when you go shopping for carpet and padding. This is imperfect advice because some of the chemicals outgassed don’t have an odor. If you can’t find a low-odor carpet, you can roll it out in an uncontaminated garage and let it air out there before you bring it indoors for installation. Furthermore, you should install the carpet with tack strips rather than an adhesive.


Many people believe natural-fiber carpets are inherently healthier. Sometimes they are, but that’s not always the case. Natural fibers are often chemically dyed or treated and wool carpet is routinely treated with mothproofing chemicals. Actually, some 100%-nylon carpets are less bothersome than some natural carpets. Whatever kind of carpet you choose, we highly recommend using a central vacuum cleaner to maintain it.


Area rugs may offer advantages over carpet. First of all, you can often find them locally made of cotton or other natural fibers at reasonable prices. Some may even been dyed using natural plant dyes. If they have any odor when new, they can usually be laundered in a washing machine or hung outdoors until odor-free. As a result, they're much easier to keep clean than wall-to-wall carpet. If a larger area rug won’t fit in your washing machine, you can take it outdoors and beat it over a line—but be sure and wear a good dust mask.


101. Wood floors are always a healthy flooring choice, right?


Traditionally, wood floors were made of tongue-and-groove boards that were individually nailed down, sanded in place, then finished. These were often low-tox floors—as long as low-tox finishes were used. Today, some wood flooring is made in a sandwich—like plywood—and held together with a glue. It's often attached to the floor with another glue. Many products are now prefinished using a variety of different materials. We prefer solid wood.


For very sensitive people the choice of wood is important. That's because they may react to one type of wood but not to another. Oak is the most common wood-flooring material, but it can have a strong natural odor. Many sensitive individuals can tolerate oak—once it’s been finished. For those who can’t, maple, beech, birch, or another hardwood may be a better choice. If you aren’t bothered by softwoods, a yellow-pine floor can be an attractive, less expensive option.


102. Does my contractor have to use asphalt-impregnated felt paper under my new hardwood floor?


He really doesn’t have to use anything under the new floor. But, the felt paper sometimes helps minimize squeaks. In older homes having a subfloor made of square-edged boards, the felt paper also helps prevent dust from moving between the individual boards. If asphalt-impregnated felt paper is used, it’ll be underneath the finish floor, so it won’t be directly exposed to the living space. As a result, the outgassing won’t be serious. But just to be safe, we don’t use it. Instead, we usually use builder’s foil. We get it in 3'-wide rolls made of Kraft paper with aluminum foil on both sides.


103. What’s the healthiest finish for hardwood floors?


Selecting a low-tox finish is actually the most important health decision with wood flooring. Over the years, shellac, acrylic, urea-formaldehyde, and other resins have been used in floor finishes. More recently, water-based urethane finishes have become popular. They’re durable and easy-to-maintain, and they outgas quickly. We often talk to sensitive people who tolerate them less than a week after application. You should stay away from oil-based urethanes because they often take months to outgas completely. Many of the manufacturers of prefinished flooring are now using the newer water-based urethanes.


Personally, we don’t like to stain wood floors. We like the natural color variation of the wood. But if you want a stain, simply choose a water-based version that doesn’t have much odor. Some are quite strong, but the milder ones will usually be sealed in by the water-based urethane finish. If you’re very sensitive, you’ll probably want to have a sample of flooring that’s been stained and finished to test for personal tolerance.


By the way, water-based urethane finishes can be used in many different applications. We use them on furniture, cabinets, interior doors, and trim.


104. Is linoleum a healthy flooring option?


Real linoleum is made with linseed oil, pine resins, powdered wood, and pigments on a jute backing. It’s an attractive and natural product, but it has a fairly strong odor when new. So, it’s not always tolerated by sensitive people. Because it’s subject to water damage, it must be coated with a sealant (which can also be bothersome) to protect it, and it isn’t a good idea to use it in very wet areas like bathrooms. Linoleum must be attached to the floor with an adhesive (use a water-based version!), but in the right situation, it can be a durable and long-lasting floor covering.


105. Can vinyl be a good flooring choice?


Vinyl flooring can also have a strong odor when new. But, some sensitive people have had good luck rolling it out in an uncontaminated garage—or in a well-ventilated, unused room—until it airs out before installing it. Vinyl is more resistant to water than linoleum, so it can be used in damp areas.


Vinyl is usually available in wider widths than linoleum. That means it can sometimes be installed without an adhesive. For example, if a room is less than 12' wide (the usual width of a roll of vinyl), you can remove the baseboard trim, cut the vinyl carefully to fit, then reinstall the baseboard on top of it to hold it in place. You’ll need to use a thin wood or aluminum threshold at the doors. As an alternative, self-stick vinyl tiles have an adhesive that’s sometimes not too odorous.


106. I’d like to use ceramic tile for my floors, but isn’t it expensive?


There’s actually a wide range of prices for ceramic tile. Some discount building centers have very good prices on glazed floor tiles, and some tile companies sell slightly imperfect tiles (seconds) at a discount. Seconds often have minor color imperfections or tiny chips on an edge that can only be seen if you get down on your knees and look carefully. But, ceramic tile can still be costly because of the labor involved. If you’re handy, and regularly take on home-repair projects, you can save a great deal of money by installing ceramic tile yourself. The few simple tools you’ll need (nippers, tile cutter, trowel, and grout squeegee) can either be purchased or rented.


We like ceramic-tile floors a lot. We think they’re one of the healthiest, most attractive options available. If you plan to live in your house for some time, you should realize that they’re also very long lasting. You’ll have to replace vinyl several times before a ceramic-tile floor is worn out. So, in the long run, ceramic tile can be very cost effective.


107. Aren’t ceramic-tile floors uncomfortable to stand on?


Some people don’t like ceramic-tile (or concrete) floors because they feel they are tiring to stand on. However, you can save your feet by placing soft natural-fiber area rugs wherever you spend a lot of time standing—such as in front of the kitchen or bathroom sink, stove, etc.


Ceramic-tile floors are often cool to the touch. In warm weather, they can feel refreshing to bare feet. However, in cold climates, they can be too cold for some people. So, it pays to have a well-insulated floor. Again, natural-fiber area rugs strategically placed around the house can improve your comfort level—or you may simply be happy wearing slippers in the winter. Some ceramic-tile floors are radiantly heated, making they very warm and comfortable when it’s cold outdoors.


108. My house isn’t built on a concrete slab. Can I still have ceramic-tile floors?


Yes you can, but if you want to install ceramic tile over a wood or plywood subfloor, you should first make sure the floor is stiff enough. If it flexes too much, you’ll end up with cracked tile. One of the best ways to install tile on a wooden subfloor is to first put down a layer of cementitious board (Durock is widely available, but there are other comparable brands). For a long-lasting installation, the cementitious board is attached to the subfloor with thinset mortar and plenty of screws. Then, the tile is installed on top of that with some more thinset mortar. Once the mortar has cured, you’re ready for grout.


Cementitious boards are made of Portland cement and a few other ingredients. They’re usually 1/2" thick, and they can have a slight odor. However, once installed, the odor is rarely noticeable because it’s under the tile. Once the tile is in place, the whole assembly functions as a fairly good diffusion retarder. So, if the subfloor is made of plywood, it usually can’t outgas through the tile into the living space.


109. Are there low-odor mortars and grouts that can be used with ceramic tile?


We’ve found that most thinset mortars are relatively low-odor products that are made with Portland cement and a few additives. But, occasionally, we’ll come across a brand that has a very strong chemical odor. In one case, someone sent us a sample of a product that had a very nasty odor. It was the same brand that we’d just used on a project, and ours didn’t have any odor at all. Yet, they were being sold as identical products. As it turns out, they were made in different factories, and the suppliers of the additives were different companies. Still, most of these products generally don’t have much odor, and once they’re covered with tile, they’re usually just fine. If you get a sample before you start a project, mix it with water and sniff it to determine if there's any odor. The "bad stuff" has a very strong, synthetic-chemical odor.


Because grout is directly exposed to the living space, we usually make our own in order to avoid additives completely. For typical 1/4" joints, mix 2 parts clean, dry sand with 1 part Portland cement, then add water. Apply it like any other grout. If you want a colored grout, you can add the same natural-mineral pigments that bricklayers use in their mortar.


Many of the additives in ready-mixed grouts cause them to cure slowly. So, if you have no additives, you’ll need to do something called damp curing. That means, when you’re finished grouting, you'll need to cover the floor with a sheet of plastic for 72 hours. That’ll help the grout retain moisture, causing it to cure slowly. A few commercially-made grouts also require damp curing. They have the fewest additives, and are usually healthy choices.


110. Don’t ceramic-tile floors need to be sealed?


Yes and no. Unglazed tiles can, indeed, get dirty. That’s why they’re usually sealed. To avoid sealers (some sealers are better than others), we prefer glazed tiles because the glass-like surface is durable, long-lasting, stain resistant, and easy-to-keep-clean. Most of the time, all you need is a damp mop to keep a glazed-tile floor looking good.


The grout between the tiles can also get dirty. It’s more absorbent and more easily stained than glazed tile. We’ve found that darker grouts hide stains easier than light-colored grouts. We’ve also found an easy way to remove many common stains from grout using Fullers earth —a dry, powdered, natural clay you can usually order through a pharmacy. Mix a little Fuller’s earth and water to make a paste, apply it to the stain, and allow it to set overnight. In the morning, you can brush it off with a stiff broom, then vacuum it up.


There’s one type of sealant that works well on grout. It’s a low-tox product made of sodium silicate, which is also called water glass. When it’s applied to grout, it reacts with the calcium in the cement and forms a crystalline structure in the surface of the grout. It can be time consuming to apply—you need to use an artist’s brush—but it can be very long lasting. Brand names include Penetrating Water Stop (AFM Enterprises, Inc., 350 W. Ash St. #700, San Diego, CA 92101, 619-239-0321) and Penetrating Sealer (Aqua Mix, 9419 Ann St., Santa Fe Springs, CA 90670, 800-366-6877).


(Note: This article is part of the original HHI Archives, and was believed to be accurate at the time of writing. The views expressed in this article are those of the author, and do not necessarily represent those of The Healthy House Institute, LLC.)


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Healthy Home Basics - Interior Floors:  Created on February 3rd, 2008.  Last Modified on February 28th, 2011


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