 Waffle Rubber: (Bridgestone underlay's) This type of padding is commonly used today but often improperly. The waffle part of the padding gives it a thickness that is mostly air, and as a result, many of this type of underlay's that weight less than 255g is still too soft for today's petrochemical and light weight backed carpets. Also, despite claims to the contrary, today's "Black & Gold" rubber underlay's are of domestic weight and are inferior as they are made in light weights and have now become a marketing ploy (#), the rubber used to make these padding's is held together with clay type binders that break down rapidly with use, if a section of carpet is in a doorway or struck by direct sunlight for a sustained period, on average only after only a few months the "Black or Gold" rubber underlay will have virtually lost most it's resilience as they are less in weight/quality than that of a commercial grade 9mm blue rubber, so be aware !
 Re-bonded: (Dunlop underlay's) This type of padding is used most often by the floorcovering industry. It is made from of scraps of the high density foams used in furniture making that are bonded together. Re-bonded padding comes in various thickness', colours and densities . The density is rated at so many kilograms per sq metre. For example, a 2.5 kg re-bonded underlay would weigh 2.5 kg (5.5 lb) per cubic metre (unless stated otherwise). The carpet and rug institute recommends a pad of at least 1.15 kg and 8 mm thickness for light traffic (your living room), and a pad of 3 kg and 8 mm for heavy traffic (hallways). These are minimum guidelines, and I suggest that a 6 to 8 lb+ pad for longer wear. Also, if you want a little more luxury, you can use a thickness of 12 mm (1/2 inch).
 SPECIAL NOTE ON RE-BONDED: In Dec. of '96 it was learned that some of the chemicals used in making Re-bonded underlay (Namely 4-PCH - Phenge Cycololexene-) have had an adverse effect on certain carpets. The off gas from Re-bonded has caused some carpets to exhibit yellow blotches on the surface of the fibre. This event seems to happen most often with commercial and Berber type carpets. Ask your dealer if he is aware of such problems? He may not volunteer or know about this information, but it does happened.
Textile and Fibre underlay: (Smith Family, United Bonded & Master Felt underlay's) These Traditional underlay's are used when one wants to limit the movement in a piece of carpet and they range in thickness between 6mm and 14mm. These underlay can be made form a blend of jute, hair, wool, cotton, synthetic fibres & recycled textiles.
Most often these pads are used under area rugs, under commercial carpets, Axminster carpet and under some Berber carpets. The key here is density and bedding qualities. Stay with at least 1590g per sq mt (3.5lb) density on the synthetic fibre BACKED carpet. For quality carpets we recommend the lightest weight of 2270g (5lb) density with a 60% Hair and 40% Jute pads, the heaviest weight goes up to 3640g per sq mt density (8lb).
Slab Rubber (Double Bonded Installation) (NB: Two areas of caution recommended when using this type of underlay with our natural floorcoverings. 1. the outer cut edges should to be tucked away by leaving a 5~8mm perimeter gap as with smoothedge or the ends of the cut fibres will fray a little during installation and especially during normal vacuuming, cleaning & over time. 2. When installing double bond underlay with the existing smoothedge that is 8mm high, if you fail to use a 6mm or thicker underlay +glue, will create a visible step-up from the underlay to the smoothedge.) However, these commercial underlay's are the ultimate in luxury and long wear one could use a 4.7~6mm thick 1'390g ~1'800g m2 density slab rubber underlay. Unlike the waffle rubber padding, slab rubber does not contain big ripples of air. This pad feels much like a Very Heavy Re-bonded foam, but will resist furniture indentation and crushing for a much longer period of time. I recommend this pad for the highest of traffic areas or Rugs. This type of underlay is now one of the most used in a quality commercial installation as this underlay was designed to be stuck directly to the sub floor with the Floorcoverings being stuck to it, making this type of underlay one of the best especially, if you have radiant under floor heating. If you can afford this type of underlay you will not regret the extra cost incurred as the quality will long remain after the price is forgotten.
Foam Sheet Underlay: This type of padding is made from urethane foam and is available in different densities and thickness'. Generally this type of pad, regardless of the thickness, is not recommended for heavy traffic of any kind. All that air under the carpet just causes the carpet to move up and down to quickly & so much that the backing (*) soon breaks down.
Frothed Foam: Some of this padding is a super dense urethane is approx. 6mm (1/4") thick and extremely durable. Recently a heavy version of this type of pad was recommended by the makers of carpets. This pad has virtually no VOCs (off gassing), can be used under all carpets. It is clamed that it will, reduce furniture indentations, prolong the life of your carpet better than any Re-bonded, fibre, waffle rubber or prime foam. It cost about the same as a good slab rubber padding and will last a long time.
Special Circumstances: There are certain carpets that require unique pad usage. One of these is a woven carpet. These carpets should be installed over a extra heavy super dense padding. In regards to radiant heated floors, if one looks at the R values of the various types of cushioning, it becomes readily apparent that SFRP (Slab Foam Rubber Pad) may be one of the best choices and even then, the thinner the better. SFRP in 6mm (1/4") thickness has an R value of only 0.31 - the hands-down winner by a massive margin. It has even 1/2 the R value of it's nearest competitor, Waffle sponge rubber, at 0.60, Frothed foam also works well with radiant heated floors but at 0.66, is better than some choices, but doesn't come close.
Acoustic Underlayment (Soundproofing underlay): This type of Layment is designed to be installed beneath an Underlay, it can also be glued to floor or installed above a Ceramic Floor to create as safer environment !
(*) Modern carpets have a secondary backing that gives this type of carpet its dimensional stability & strength, as in a woven carpet is the primary backing and usually stronger ! |