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Frequently Asked Questions




What are the steps that I can expect a certified professional to take when cleaning my carpet?


The principles of carpet cleaning are listed in the S100 Standard and Reference Guide for Professional Carpet Cleaning, last published by the IICRC in 2002. The principles of carpet cleaning include:

Dry Soil Removal - thorough vacuuming using an upright vacuum with brush agitation and high-efficiency double-lined collection bag, or a final filter, to remove up to 99% of particles at 1 micron.

Soil Suspension - This involves the application of properly specified, formulated and mixed preconditioning agents designed to separate soil from fibers. There are four fundamentals involved in soil suspension: application of preconditioning chemicals; using heat or temperature to speed chemical reactions; agitation for proper chemical distribution, and providing dwell time so that chemical reactions can be completed before soil extraction is attempted. The acronym "CHAT" makes the fundamentals of soil suspension easy to remember.

Soil Extraction - Any method of cleaning must physically remove soils if it is to be successful. Soil removal takes place with absorption, wet vacuuming, rinsing, and even dry vacuuming. The most popular method for soil removal among professionals is hot water extraction.

Grooming, as necessary - Grooming has little to do with physical soil removal; however, it is needed to eliminate pile distortion and matting, to properly distribute additives, such as carpet protectors, and to create an even appearance for your inspection.

Drying - Damp carpet resoils rapidly, creates potential for slip-fall problems and ultimately, can grow bacteria with associated odor.


What is the proper way to deal with furniture indentations in carpet?


Indentations from furniture re-arrangement are a normal phenomenon in carpet. Sometimes, the situation is self-correcting when the furniture is moved and the carpet backings and pile are allowed to re-acclimate. In other cases, vacuuming coupled with light brushing can bring up the indented areas. In extreme cases, the indentation can be covered with a damp towel and steamed with an iron for a few seconds, followed by brushing while warm to "resurrect" the pile in that area. Nylon carpet pile (about 70% of residential carpet) responds particularly well to this procedure.

There are, however, limitations brought on by the type of pile fiber. If the pile is made of non-resilient olefin, as in olefin Berber or level-loop olefin commercial carpet, the indentation may be permanent. That's a characteristic of the fiber. This is why non-resilient olefin often is combined with resilient nylon in several popular carpet styles.


How often should I get my carpets cleaned?


Frequently used carpet should be professionally cleaned by a qualified technician at least annually - perhaps a little longer interval for infrequently used carpet and even sooner for carpet in homes occupied by respiratory sensitive or allergic persons; or in homes with indoor pets.

The following chart from the IICRC S100 Standard and Reference Guide for Professional Carpet Cleaning serves as a guideline for recommending cleaning frequencies for carpet. They consider traffic, soil rating, vacuuming schedules, spot cleaning schedules, and professional interim and restorative cleaning.


How long does it take mold to start growing in wet carpet?


There is no defined time frame to predict when mold will grow in carpet. For any material to support common indoor mold growth, it must:

  • be organic,
  • be damp or wet,
  • have a moderate temperature (68-86ºF),
  • be in a stagnant air environment, and
  • have these conditions present for several days.

Most tufted carpet is made of plastic face yarns and backings, and synthetic latex. There is nothing organic to support mold in the carpet itself. Therefore, mold cannot technically grow on carpet. However, average household soil is about 40% organic (12% cellulose, 12% protein, 10% oils, 6% food stuffs); therefore, mold can grow on the soil in carpet given the right conditions listed above.

However, if carpet is kept clean and dry, there is little or no possibility for mold growth. Even with soiling and normal household conditions found in most homes, it takes considerable time for mold to grow on carpet soil, and then only if dampness is present.


What is the standard drying time when carpet is cleaned?


The IICRC S100 Standard and Reference Guide for Professional Carpet Cleaning specifies:

Section 7.5, Drying
... When cleaning carpet, it is highly recommended that drying occur within six to eight hours or less: however, drying time must not exceed 24 hours. Failure of the professional to implement drying procedures could result in a variety of after-cleaning problems. Often, occupant cooperation is needed to expedite drying.

With normal temperature and humidity coupled with use of your heating ventilation and air conditioning (HVAC) system, the carpet should be dry in much less than 24 hours. If it stays damp longer than that, the opportunity for microbial growth and associated odor arises.



What steps should I take to maintain carpet in a high-traffic area on a daily basis, and to deal with spills and stains?


The following steps should be taken when dealing with carpet in a high-traffic area:

  • It's a good idea to keep sand, grit and grass clippings off walkways outside entries to prevent inward tracking of these abrasive soils.
  • Purchase a properly sized entry mat (the bigger the better, but there must be room for at least two steps to sufficiently wipe soil from feet before encountering the installed carpet). Nylon face, vinyl back for better moisture and oils absorption, combined with the resiliency necessary to collect a quantity of particle soil. The IICRC suggests a rental mat, since that guarantees frequent maintenance. Place entry mats on hard surfaces rather than on carpet where they can trap moisture or cause plasticizer migration.
  • Vacuum, vacuum, vacuum; daily, especially after major events. The sooner you collect soils from the surface, the easier it is to remove them. For most carpet, you should use an upright vacuum with brush agitation, unless your canister vacuum is particularly well designed. The wider the head, the more efficient.
  • Use high-efficiency double-lined poly-fiber collection bags. This reduces periodic maintenance such as dusting of furniture, Heating, Ventilation and Air Conditioning (HVAC) filter exchange.
  • Typically, deep cleaning should be accomplished on at least a semi-annual basis, with no more than two entry and high-traffic area "rinse" cleanings between the deep cleaning. This is dependent on traffic and daily maintenance as well. At a minimum, some attention should be given to primary entry areas on a quarterly basis.
  • If spots are treated immediately, most will respond with plain warm water and very little mild detergent added.
  • Make sure the HVAC system is slightly positively pressurized as well (air going out when doors are opened, rather than being sucked in). Proper air exchange rates can be calibrated according to ASHRAE regulations for the building with a trained HVAC contractor.
  • Ensure proper air filtration through the HVAC System. High-efficiency pleated filters, rather than inexpensive fiberglass filters, are recommended.


What is the best method of carpet cleaning: dry foam method or steam extraction?


Various methods of cleaning have different functions, both in interim maintenance and restorative cleaning.

According to a survey conducted by Cleanfax, a cleaning industry magazine, some 88.6% of the professional carpet cleaners are using hot water extraction as their primary cleaning method. Dry foam cleaning was used by 1.5% of the professionals surveyed.

Second, both Shaw Industries and Mohawk, who together manufacture over two thirds of the world's carpet, recommend hot water extraction cleaning.

Whatever method you choose, it is important to use an IICRC-Certified Professional for your cleaning work.

Pet-related Deodorization and Decontamination


How can I get the pet odor out of my carpet?


Most consumers without specialized chemicals and extraction equipment may not be able to completely remove pet urine from wall-to-wall carpet or area rugs, because many products only provide temporary relief.

Professionals have enzyme deodorants or powerful oxidizing agents that digest or destroy odor-causing protein and/or bacteria that are the source of urine odor. More importantly, they have efficient extraction cleaning equipment that is able to flush suspended or dissolved residues from the carpet to leave it residue and odor-free. The IICRC recommends contacting an IICRC-Certified Firm that has personnel who are certified as Odor Control Technicians. Remember that if the animal still resides in the house, he or she will almost inevitably re-mark his or her territory, thereby causing the odor to return.

Color Repair


I have bleach spots on my carpet. How do I get the color back in my carpet without doing more damage to it?


Chlorine bleach potentially does two things to nylon carpet fiber. First, it removes color - that's obvious. Second, it may damage the polymer dye sites, depending on how concentrated it was when spilled. With wool, the fiber may be dissolved or significantly damaged.

If diluted bleach was spilled on the carpet, chances are good that it can be neutralized (this is essential) and re-dyed with appropriate dye stuffs. However, it takes a trained and experienced technician to re-dye carpet to the correct hue color) and shade (grayness), without circles or a variety of other problems.

Carpet Inspection


Dark shadows are appearing under furniture sitting on our light-colored carpet. The shadows outline the object that was on top of the carpet. The shadows appear to be almost black in nature and don't lighten or disappear with regular vacuuming. What causes these shadows and what can I do to clean them up?


When inspecting carpet for problems, it’s first necessary to ascertain a number of facts, including but not limited to:

  • Fiber type
  • Construction
  • Dye techniques
  • Backings
  • Installation
  • Cushion
  • Sub-flooring
  • HVAC system
  • Lighting (fluorescent, incandescent, natural)
  • Soiling

Almost any of these can have an impact on the problems you are experiencing with your carpet. In order to gather all the facts and to evaluate the influence of external factors normally takes an on-site inspection performed by a trained professional certified by the IICRC.

Alternatively, you can contact the carpet retailer who sold you the carpet. Reputable carpet manufacturers have warranties on their products and they can commission an inspection by a trained professional in the area. Be sure that the inspector is IICRC-Certified and can prove it by showing you a wallet card. This will be your assurance of an impartial evaluation of your carpet’s condition.

Upholstery Cleaning


How often should upholstered office chairs be cleaned? Where in the IICRC reference material would I find this information?


Unknown to most commercial end users is the fact that commercial upholstery, unlike residential, experiences a lot more daily soiling and wear and tear. Commercial upholstery should be cleaned at least annually by a professional cleaning service that knows how to remove maximum soil, perhaps semi-annually in heavy use situations. The increased use life of the upholstery and the savings in productivity will pay for the cost of cleaning.


How do you clean pen ink off of microfiber upholstery?


In this case, there are two options:

If the upholstery is simply a cushion, a professional dry cleaner may be able to use a spotting board that vacuums the back while treating the face. He would have the ability to use a steam/air gun in ink removal as well. Unfortunately, there are few professional credentials for dry cleaners to determine qualification.

Second, an IICRC certified; Master Textile Cleaner(MCT) may be able to help. With proper techniques, the stain should come out.

Indoor Environmental Quality


How can I get rid of “new carpet odor?”


New carpet odor comes from a reaction between styrene and butadiene, the components of synthetic latex or styrene-butadiene latex (SBL). There is no natural latex used in carpet today; therefore, there are none of the latex proteins that cause allergic reactions in sensitive people, as might be the case with latex gloves.

When new carpet is installed, the old carpet should be thoroughly vacuumed with a high-efficiency-filtered vacuum cleaner before it’s disengaged. If it’s particularly filthy or highly contaminated with mold or pet urine, it is advisable to roll it in plastic as it is removed. Then the sub-floor should be vacuumed before the new carpet is installed.

Much of the suffering that people experience during and immediately after new carpet installation is directly related to aerosolized dusts and biological fragments (bioaerosols) that are rendered airborne when the carpet is “ripped out.”Positive ventilation helps a good deal here as well.

In addition, it’s important to consider other sources before assuming that the odor is caused by the new carpet.

Water Damage Restoration


Is there an IICRC method for handling sewage backup or toilet overflow?


The procedures for processing sewage backflows are complicated and fraught with many health hazards. As such, we cannot in good conscience recommend that this work be undertaken by consumers without specialized training and experience. It must be dealt with by a professional.

Procedures for processing sewage contamination are covered in the IICRC’s Water Restoration Technician and Applied Microbial Remediation Technician certification categories. Further, the IICRC S500 Standard and Reference Guide for Professional Water Damage Restoration covers Category 3 (e.g., sewage) restoration.

Mold Remediation


Is it possible to restore clothes that have been affected by mold?


Foremost, any garment or fabric that has not suffered physical deterioration or discoloration as a result of mold growing on it, and that is washable (typically, a minimum of 130ºF for at least 10 minutes), can be restored completely. That goes for bacterial contamination as well, as evidenced by hospitals daily as they wash linens, gowns, surgical drapes, etc.

Dry cleaning also does a good job when evaluated and cleaned - often twice - by a qualified professional. Again, this assumes no deterioration or discoloration of the garment. Ultimately, sampling and evaluation by a qualified environmental professional can be used to confirm remediation of the garment.


The FAQs contained herein were compiled by Jeff Bishop, IICRC Technical Advisor. Neither the compiler, nor the IICRC, nor any other person acting on their behalf makes any warranty, express or implied, with respect to the use of any information, method or process related to this publication, and that such use may not infringe on any privately owned rights; or assumes any liability with respect to the use of, or for direct or consequential damages resulting from the use of any information, method or process related in this publication; or has any liability for damages that result from any negligent act or omission involved in the preparation of the material contained in this publication.

Any implied warranty of merchantability of fitness for a particular use is specifically excluded. Compiler reserves the right to make corrections and updates as it deems necessary.

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