Buying New Carpet?  What You Want To Know Before You Decide.

photo of many different colors of carpet

The Entire Article Provides Comprehensive Information on Carpet, Pad / Cushion & Carpet Care

Part 3 of 4 

Choosing The Right Carpet Cushion/Pad

Carpet Pad is as important as the grade of carpet.  With less expensive carpet, Cushion / Pad can be more important. 

TIP: If you want to keep purchase cost down, buy the next lower grade of carpet and install a higher grade of pad under it. 

This is Part 3 of a 4-Part Article On Carpet & Carpet Pad / Cushion:

This section describes the different types of carpet pads and discussed the merit of anti-microbial (mold) treated carpet pad when installing carpet over concrete floors. Lastly, it describes suggested prep-work of concrete floors in slab-foundation homes when visible mold, or mold-odor is present.

Carpet Pad’s Primary Purpose Is To Absorb Impact

Many people think a thicker pad will: 1. protect the carpet better & 2. Be more comfortable under foot.  In reality, these two desirable traits have little to do with pad’s thickness, and everything to do with the pad’s density.  A pad that’s too thick can actually damage carpet (more on this later).

The density of the pad is what extends carpet life — and higher density pads do not need to be as thick.  In reality, there is a recommended maximum thickness for carpet pad.  That thickness is determined by the style of carpet.  The maximum carpet pad thickness recommendation is just under 1/2 inch.  The maximum thickness becomes less for some styles of carpet (such as berber).

A low-density pad flattens out when you walk on it — and won’t feel comfortable or soft.  Because a low-density pad flattens out, it absorbs little of the impact-force created as you walk on the carpet.  When the pad is low density, most of the impact-force is absorbed by the carpet.  Impact-force causes the carpet-pile to crush & matt quickly.  The end-result is that the carpet looks good for only a brief time after it’s vacuumed.  A poor quality pad contributes to the carpet wearing out (or “uglying out”) sooner than the same grade of carpet installed over a higher grade of pad.

carpet that is matted

That’s Ugly Carpet!  It’s pile is crushed & matted.

Crushed & matted carpet-pile looks terrible.  Carpet can wear out — or “ugly out” to the point that you can’t stand looking at it any longer.  There are two ways to lift crushed carpet-pile to make it look better, regardless of its age.  Vacuuming and Hot Water Extraction Cleaning (details in our Carpet Care Section) are the primary ways.  If you have longer nap carpet (like frieze or top quality plush) using a carpet-rake can help lift carpet-pile too.  Once the pile is lifted, the grade of carpet  pad affects how quickly the carpet-pile crushes again.

before and after hot water extraction method of carpet cleaning  before and after vacuuming carpet

Before & After Hot Water Extraction Cleaning                                      Carpet Pile Lifted During Vacuuming

carpet rake for removing pet hair from carpet

Carpet Rake That Also Helps Remove Pet Hair

Click Here For More Details, Or To Purchase This Carpet Rubber Bristle Carpet Rake


Note: When carpet-pile is crushed or matted, you are walking on the sides of the carpet-tufts.  This contributes heavily to carpet wear, as the tufts are designed to be walked upon on their tops.  The faster carpet matts, the faster it’s wearing out.

While many people believe the purpose of carpet pad /  cushion is for comfort under-foot, the primary purpose of carpet cushion is to absorb impacts.  Repeated impacts to carpet can cause: Rapid matting of the carpet-pile, Unnecessary stress on the carpet-fiber, Carpeting to stretch, and Separation of the primary & secondary carpet-backings (the primary problems). The best performing carpet cushion actually provides less comfort under foot (because it’s so dense).  It improves the carpet’s appearance and extends carpet life by doing a great job of absorbing repeated impacts.

The Two Purchase-Decision Characteristics For Cushion / Pad Are Density & Thickness  

The higher the density, the thinner the pad can be.  The two most common mistakes consumers make is to purchase a carpet padding that is too soft (not dense enough)   and /or is too thick.

  • Carpet cushion that is too soft (not dense enough) flattens while being stepped on.  This forces the carpet to absorb the remaining impact-force, shortening the carpeting’s life.
  • Carpet cushion that is too thick causes stress on the the carpet.  If this occurs, recurring stretching can damage the carpet’s backing & face-fiber, shortening the carpet’s life.  Over time, the carpet can develop wrinkles and must be restretched.  Restretching of wrinkled carpet must be done in order to prevent further damage.  Restretching carpet in a furnished home can be a large undertaking.

Carpet Wrinkles

carpet wrinkles

A carpet wrinkle is cause for concern.  A wrinkle in your carpet tells you something has gone wrong.   If the wrinkle is not removed promptly, further carpet damage will occur, shortening the carpet’s life.  Carpet wrinkles can also create trip-hazards.

Top Reasons Carpet-Wrinkles Occur:

  • The pad is not dense enough — allowing too much impact-force (that the carpet must absorb).
  • The pad is too thick — causing excess carpet movement when it’s walked upon.
  • Carpet became overly wet (due to improper cleaning, or a flood).  Improper hot water extraction cleaning is often the cause, due to excess water remaining in the carpet.  Having carpets professionally cleaned minimizes the chance of over-wetting.

TIP:  If you are using a hot water extraction carpet-cleaning machine, move it slowly, so it has enough time to remove as much water as possible.

TIP:  If you are using a carpet-cleaning machine, make a second pass over the carpet (without dispensing water) to ensure you have removed as much water as possible.

  • Dragging heavy pieces of furniture over carpet can stretch it.  Find a helper and carry the furniture to it’s new spot.
  • Humidity can be factor during summer.  In climates with high summer humidity (like DFW) humidity penetrates the carpet, causing it to swell.  Humidity-based carpet wrinkles typically flatten down once humidity levels drop.  If they don’t, consult with a carpet installer to determine if restretching is needed.

Types of Carpet Cushion / Pad

There are a number of different types of carpet pad / cushion, each with its own benefits and downfalls.  Within this section, we will describe all of today’s carpet pads.  We also discuss the density of each type of pad.

Different types of carpet cushion weigh different amounts.   The weight of the cushion is determined by the type of cushion.  Pad / cushion weight is only relevant when choosing among the same type of cushion.

Carpet cushion comes in different thicknesses. ** Thickness affects how the carpet feels underfoot, and is not a performance-characteristic.   There are recommended minimum & maximum cushion thicknesses, based upon the type of cushion & style of carpet.

** Note: The Carpet & Rug Institute advises pad should be no more than 7/16 of one inch thick (7/16 is just under 1/2″).  The maximum thickness lowers for some styles of carpet (such as berber).

Density (per cubic foot) For Different Carpet Pads: 

  • 2.2 pounds per cubic foot — Urethane Foam
  • 4–8 pounds per cubic foot — Bonded Urethane Foam (also called Rebond)
  • 6–8 pounds per cubic foot — Felt / Jute / Fiber
  • 25 pounds per cubic foot — Waffle-Rubber
  • 33 pounds per cubic foot– Flat / Slab Rubber

Urethane Foam

Higher-density urethane foam can be a good choice, though bonded / rebond is better.  Additionally, bonded foam is a “green” product.  It reuses (new) scraps of high-density foam from sources such as furniture manufacturing.

urethane foam carpet pad

R-Value Insulating Factor For Urethane Foam Cushion (DFW attic insulation code = R-38)

Urethane Foam 2.2 pound per cubic foot 1/4″ R-1.08
3/8″ R-1.62
1/2″ R-2.15


Bonded Urethane Foam (Rebond): 

(Also known as “rebond”).  This cushion type is the most popular cushion / pad sold today.  It is made from reclaimed (not recycled) scraps of high-density urethane foam from sources such as furniture & automotive manufacturing.  The pieces are bonded together to form carpet cushion.

The Carpet Cushion Council recommends a bonded cushion be:

  • Light-Traffic Areas:  At least 5 pounds density & 3/8″ thickness.
  • Heavy-Traffic Areas: 6.5 pounds density & 3/8 inch thickness.
  • This is a good example of how a  higher density cushion / pad can be thinner and still protect the carpet.

rebond carpet pad

Rebond Carpet Cushion / Pad

R-Value Insulating Factor For Bonded / Rebond Foam Cushion (DFW attic insulation code = R-38)

Bonded Urethane 4-8 pounds per cubic foot 1/4″ R-1.05
3/8″ R-1.57
1/2″ R-2.09

NOTE: One concern with rebond carpet cushion is that it may contain a chemical compound known as BHT (butylated hydroxy toluene).   BHT has the tendency to produce yellowing in some carpets over time.  It’s recommended that you ask for written assurance the rebond carpet pad you chose does not contain BHT.

TIP: If you have rebond carpet cushion, and yellowing has occurred, rinse with white vinegar before applying a detergent solution. Detergent solutions have the tendency to permanently set the yellowing.


Because of its waffle texture, this pad’s thickness-measurement includes air (parts of this pad sit above the floor, where the waffle-pattern indents).   Waffle rubber pad has the 2nd highest insulating ability (felt is first, but will feel harder underfoot).   Today’s waffle rubber carpet pad lasts & performs better than earlier versions.

waffle rubber carpet pad

Waffle-Rubber Carpet Cushion / Pad

R-Value Insulating Factor For Waffle Rubber Cushion (DFW attic insulation code = R-38)

Waffle Rubber 25 pounds per cubic foot 1/4″ R-0.62
3/8″ R-1.00
1/2″ R-1.33

Flat Rubber

The best performing carpet pad is 19 -22 pound density flat-rubber.  This carpet padding is pricey and can be difficult to find.  Due to high cost of flat rubber cushion, many buyers don’t choose it.

Flat / slab rubber cushion has the most density.  A cushion’s density determines the minimum cushion thickness recommendation.  Example:  The minimum thickness for Prime Urethane cushion is 3/8″ (a little under 1/2″) — while the minimum flat/slab rubber cushion is 1/4″.

flat rubber carpet pad

Flat / slab Rubber Carpet Cushion / Pad

R-Value Insulating Factor For Flat / Slab Rubber Cushion (DFW attic insulation code = R-38)

Flat / Slab Foam Rubber 33 pounds per cubic foot 1/4″ R-0.31
3/8″ R-0.47
1/2″ R-0.62


Felt Cushion 

Some felt cushion is made of scrap fibers.  Fiber cushion made only of jute perform better than scrap-fiber versions.  Felt cushion has the best insulating ability.   While this cushion absorbs impact-forces well, it does not provide much comfort.

felt carpet pad

Felt Carpet Cushion / Pad


R-Value Insulating Factor For Felt / Hair / Jute Cushion

Fiber/Hair/Jute 6-8 pounds per cubic foot 1/4″ R-0.97
3/8″ R-1.46
1/2″ R-1.94


Brand Name Carpet Cushion / Pad

Some carpet manufacturers sell their own Brand of carpet pad / cushion.  “SmartCushion” is Mohawk’s brand name.  In Mohawk’s case, if you install Mohawk carpet cushion under Mohawk carpet, the Abrasion-Wear Portion of the Carpet’s Warranty is extended (on select carpets).  Consult with a carpet retailer for details.

mohawk smartcushion logo

mohawk smartcushion pad close up photo

mohawk smartcushion showing back side does not have moisture barrier

Features of Mohawk SmartCushionTM:

  • Visco-elastic memory-foam construction.
  • Spillsafe Moisture-Guard prevents moisture from soaking downward into the cushion.
  • NOTE: Moisture Guard Moisture-Barrier Is Only On The Top.  This Prevent Liquids Going Downward Into The Pad — While Allowing Water-Vapor To Pass Upward Through The Pad (which is important with concrete floors).
  • Antimicrobial Additives to help inhibit the growth of mildew, mold, & fungus.
  • Sound-Transmission Class rating (54) & Impact-Insulation Class rating (72) means a more quiet (two-story) home.
  • Insulation Value R-2.1.
  • Made from reclaiimed (not recycled) foam-trimmings (from furniture & mattress industries).  90% post-industrial material.
  • Non-Allergenic
  • LEED Certified * & Environmentally-Friendly

* LEED stands for Leadership in Energy & Environmental Design.  LEED v4 (Fall 2013) contains substantial changes for Building Products.  Now, while being evaluated for LEED Certification,  Building Products are also measured for their impacts on human health


With Concrete Floors, Choose A More Health-Friendly Carpet Pad

A Pad / Cushion With An Anti-Microbial Helps Minimize Mold Growth  

mold growth on concrete floor and under carpet pad

Shown: Black Mold Growth on concrete floor under the carpet & pad.

mold in carpet and pad

Shown: Both The Pad & The Carpet Backing Is Molded

Why You Want Pad With Antimicrobial-Protection Over Concrete Floors 

The porous nature of concrete allows water-vapor to move upward through the slab from the ground below.   Over time, carpet & pad will accumulate some dust & dirt, and it will move all the way down to the concrete floor.  Then, mold has what it needs to grow is (moisture & food).

In new homes built today (and most homes in general) a vapor-retarder was laid over the layer of gravel (under the slab).  Then, cement is poured over the vapor-retarder (once dried, cement becomes concrete).  With the vapor-retarder under the slab, moisture must move upward to the surface to evaporate.

slab foundation home ready for cement

Diagram showing a vapor-barrier under the concrete slab

slab foundation home ready for cement

The photo just above is what the foundation of a new-construction DFW slab-foundation home looks like just before cement is poured.  The (black) vapor-retarder was installed to minimize moisture coming up from the ground through the slab. Even with the best moisture-retarder installation, some water-vapor will make its way into the slab foundation’s concrete floors.  It will move upward to the top of the concrete, where it can evaporate into the home’s indoor air.  

The is normal & common, and (in itself) poses no health hazards.  With carpet, dust & dirt gets into the carpet pad, and makes its way to the concrete floor, where it has access to water-vapor.  At that point, the potential for mold colonization & growth exists. 

Mohawk SmartCushion (among other brands) Has An Anti-Microbial Added 

  • Mohawk’s SmartCushion Guards against the growth of mildew & mold.  This feature is especially important for a slab foundation home’s concrete floors.
  • SmartCushion includes a moisture-barrier, to keep liquids from entering the pad from above (but let’s water-vapor pass through the pad from below).
  • SmartCushion is LEED Certified *  This means SmartPad meets LEED Certification Standards regarding human heath impact.
  • On A Side Note: MoHawk SmartStrand carpet is only renewable carpet-fiber that is Certified Free Of Harmful Substances.

* LEED stands for Leadership in Energy & Environmental Design.  LEED v4 (Fall 2013) contained substantial changes for Building Products.  Now, Building Products are also measured on their impacts on human health.

  • Source: Mohawk SmartCushion website
  • Source:

NOTE: SmartCushion is likely not the only antimicrobial carpet pad.    It is likely not the only LEED Certified carpet cushion / pad.

Don’t Use Two-Sided Moisture-Barrier Carpet Pad / Cushion On Concrete Floors

A Moisture-Barrier Carpet Cushion / Pad, with barriers on BOTH THE TOP & BOTTOM is not for use over the concrete floors of slab foundation homes.  It can be used anywhere the sub-floor is wood.

There is an inherent problem with double-sided moisture-barrier carpet cushion in concrete-slab foundation homes (like homes in DFW).  The slab needs to “breath”  meaning to allow moisture in the concrete to move upward and evaporate.  Two-sided moisture-barrier carpet pad / cushion will not allow the water-vapor upward through the pad.

** Carpet “breathes”—a good thing that allows the water-vapor entering the slab from underneath to exit into the building.  Then it is removed by the air conditioning or by ventilation:

** Source:

When Replacing Carpet, Consider Cleaning & Treating Concrete Floors

With Anti-Microbial Products First

  • There are two steps you can do for concrete floors to enhance protection from mold:
  • The first step is a cleaner — to help clean away existing mold.
  • The second step is a treatment — to help retard future mold growth. 

Note: The products shown below are one of many brands.

Microban BotaniClean Antimicrobial Cleaner  

BotaniClean is a Germicide & Fungicide, hospital-grade Cleaner for hard surfaces.  It requires no rinsing. It also cleans & deodorizes carpet, upholstery and fabrics.  It has a mild fragrance without harsh fumes.    EPA registration no. 34810-25-70385.

Note: This product is for cleaning surfaces that are prone to mold, or have mold actively growing.  It does not stop future mold growth.


botaniclean germicidal and fungicidal cleaner

Buy It On Amazon With This Link: BotaniClean Antimicrobial Cleaner ($25 One Gallon)

YouTube Video Describing BonaniClean BotaniClean 

Microban Disinfectant Spray is a: Bacteriostat, Fungistat, & Deodorizer Treatment

Microban Spray prevents fungal growth. It also kills allergy & disease-causing germs, bacteria, fungi, mold & mildew.  Microban Disinfectant Spray Plus can be applied to carpet, upholstery, and mattresses.  EPA Registration Number: 70385-5

Note: If you have pets, the deodorizer in Microban can leave your floors as odor-free as possible.

microban disinfectant fungicidal spray mint fragrance

  Mint Fragrance

Buy Microban Spray On Amazon With This Link: Microban Spray — Mint Fragrance

YouTube Video Describing Microban Spray: YouTube Microban Spray

microban disinfectant fungicidal spray fragrance free

 Fragrance-Free Microban Buy It Here (Amazon does not carry unscented) Microban — Fragrance Free


footer-logoThis is Part 3 of a 4-Part Article On Carpeting:

It this section you can learn the details about carpet pad / cushion.  For slab foundation homes (concrete floors) the pad can mold.  This is due to dust & dirt settling into the pad over time + water-vapor coming upward through the slab.  These two things are all mold needs to colonize and grow.  For this reason, concrete floors have special needs to minimize the potential for mold.  Their needs are explained in detail within this article.

Although Al’s is a Plumbing, Heating & A/C Company, this is one of many Home Improvement Articles found at this website.  In addition to Plumbing & HVAC articles, others include: Home Decor & Decorating, Home Staging (when selling), Replacement Windows, Renovations, Opening Up Homes into an “open floorplan” layout, Roof Shingles, Energy-Saving Upgrades & Updates, and general-interest home related articles.

Al’s Plumbing, Heating & A/C provides Plumbing & HVAC Repairs, Replacements, & Maintenance.  We service all brands of HVAC Systems, and sell new & installed HVAC from American Standard (same company as Trane), Ameristar (owned by American Standard) and Coleman HVAC (same company as York HVAC).

We also repair and replace every plumbing component in your home.  Call Al’s today to discuss any concerns or problems you may have.  We set appointments arranged for your convenience and also have 24/7 Emergency Service.