Understanding Why Some Rugs Ripple — and How Proper Cleaning Can Help Prevent It
If you’re wondering why your area rug is buckling after cleaning, the answer often has more to do with the rug’s construction and how it reacts to moisture than with the cleaning itself.
After more than 55 years in the carpet and rug cleaning business, I’ve learned that properly cleaning an area rug requires understanding much more than whether the visible fibers are synthetic or natural.
To really understand how a rug should be cleaned, you need to understand how it was constructed.
The face fibers you see may be wool, nylon, polyester, cotton, or another material. But underneath those fibers, a rug may have a completely different type of construction providing its structural support.
Some rugs use synthetic backing materials. Others use natural materials such as cotton or jute. Some have both a primary and secondary backing. Others may have latex or another coating for additional structural support.
And then there are rugs made with little or no separate structural backing at all, where the fibers themselves are woven together to create the rug.
Understanding these differences is extremely important because moisture and humidity can affect each type of rug differently.
And that brings us to one of the most common causes of waving or buckling:
Moisture Can Cause Rugs to Change Shape
In many cases, the introduction of excessive moisture or humidity is what causes a carpet or area rug to ripple, wave, or buckle.
Different fibers and backing materials can absorb moisture at different rates. As those materials become wet, they may swell. Then, as they dry, they may shrink or tighten.
If one part of a rug reacts differently than another, the result can be rippling, buckling, or distortion.
That is why understanding the construction of the rug is so important before deciding how aggressively it should be cleaned and how much moisture should be used.
What About Wall-to-Wall Carpet?
Modern wall-to-wall carpet usually has substantial structural support. If it has been properly installed and stretched correctly, buckling should not normally occur.
However, excessive moisture during cleaning can sometimes cause problems.
One common cause is overwetting the carpet.
This can happen when an inexperienced operator uses too much water or excessive cleaning pressure. Powerful truck-mounted equipment, for example, can deliver a tremendous amount of water if the operator does not understand how to properly control the equipment.
Another possible problem is inadequate vacuum recovery.
If too much moisture is left behind after cleaning, that moisture can migrate deeper into the backing materials. The backing may initially swell and, in some cases, tighten or shrink as the carpet dries.
Fortunately, many of these problems are temporary. Once the carpet dries completely and the humidity level in the home returns to normal, the carpet may settle back into place.
In more serious cases involving shrinkage or movement, however, the carpet may need to be professionally re-stretched and secured properly again.
Why Needlepoint Rugs Often Need Blocking
Area rugs can be a completely different story.
Needlepoint rugs are a good example.
Because of the tension created by the hands of the person weaving the rug, a newly made needlepoint rug may not naturally be a perfect rectangle or square. It may actually resemble more of a parallelogram.
Before the rug is sold or placed in a home, it may be sent to a specialist to be blocked into the proper shape.
At Alec’s Carpet & Upholstery Cleaning LLC, blocking has been an important part of properly caring for certain types of rugs.
The challenge is that whenever a needlepoint rug becomes wet during cleaning, the fibers and foundation can relax and the rug may begin returning toward its original shape.
Without proper blocking after cleaning, the rug may no longer lie straight or square.
Even changes in humidity over time can slowly affect some rugs and contribute to distortion.
Border Rugs Can Be Especially Prone to Rippling
Another interesting example is the border rug.
These are often relatively thin rugs with a center section made from wool and a supporting structure that may contain cotton. Around the outside is a decorative border, often several inches wide.
That border may be sewn onto the rug by hand or attached using other construction methods.
The problem is that the structural fibers in the border do not always run in the same direction as those in the center of the rug.
On two sides of the rug, the supporting strands may run in the same direction as the center section. On the other two sides, the strands may run perpendicular to them.
When moisture enters those materials, especially cotton, they may react differently as they dry.
Because these rugs are relatively thin, moisture can easily migrate into the structural fibers. If one section shrinks or tightens differently from another, rippling can occur.
The solution is often the same as with a needlepoint rug:
The rug may need to be properly blocked while it dries.
What Does “Blocking a Rug” Mean?
Many homeowners have never heard the term blocking.
Blocking is a process used to return a rug to the proper shape and hold it in that position while it dries.
Traditionally, we would place the rug on a suitable wooden platform and carefully secure one edge of the rug using finished stainless-steel penny nails.
The rug is then pulled straight and the adjoining side is positioned so the corner is perfectly perpendicular to the first side.
Once that corner is properly positioned, the remainder of that side is secured.
The same process is repeated around the entire perimeter of the rug.
The nails may be placed only an inch or two apart, depending on the rug and the amount of control needed. When completed, the rug is held firmly in a perfectly straight square or rectangular shape.
The important part is that the rug remains properly blocked while it dries.
Once completely dry, the nails can be removed.
When the process has been done correctly, the rug should retain its proper shape and lie flat without the ripples or distortion that might otherwise occur.
What About Oriental Rugs?
Oriental and other handwoven wool rugs present another set of considerations.
Some professional rug-cleaning facilities clean these rugs using full immersion washing or wash pits where the entire rug is saturated.
There are situations where thoroughly flushing an entire rug can be very important.
One example is extensive pet urine contamination.
Urine doesn’t simply remain on the surface of the rug. It can penetrate deeply into the fibers and foundation, leaving behind salts and odor-causing residues.
When a rug has significant urine contamination, thoroughly flushing the rug may be necessary to remove as much of the contamination as possible. In those situations, repeated washing and rinsing can be the most effective approach.
However, in my experience, not every Oriental rug requires complete immersion simply because it needs routine cleaning.
Most everyday soil is introduced from the top of the rug, where people walk. The face fibers are typically where the greatest concentration of soil is found.
My approach has always been to carefully evaluate the condition of the individual rug and clean it according to its construction, soil level, and specific problems rather than automatically using the same cleaning method for every rug.
The more moisture introduced into a rug, the more important it becomes to understand how the fibers and foundation may react.
Heavy saturation can sometimes contribute to shrinkage, distortion, or rippling, particularly when different materials within the rug react differently to moisture.
The Bottom Line
If your area rug is waving or buckling after cleaning, don’t automatically assume the rug has been permanently damaged.
Sometimes the problem is temporary and will improve as the rug finishes drying and the humidity level returns to normal.
Other times, however, the rug may need professional attention.
The key is understanding that an area rug is much more than the fibers you see on the surface.
The construction underneath those fibers — the foundation, backing materials, direction of the supporting strands, latex coatings, and other structural components — can all affect how a rug reacts to moisture.
After more than five decades of cleaning carpets and rugs, I’ve learned that there is no single cleaning method that is appropriate for every rug.
Understanding how the rug was made is one of the most important parts of knowing how to clean it properly.
And sometimes, preventing ripples and buckling isn’t just about how you clean the rug.
It’s about understanding what needs to happen after the cleaning is finished.
If you have questions about your area rug or need professional area rug cleaning, contact Alec’s Carpet & Upholstery Cleaning LLC. You can also learn more about our professional [area rug cleaning services] on our main website.
Have a Question for Alec?
If you have a question about carpet, upholstery, or area rug cleaning, you can contact Alec’s Carpet & Upholstery Cleaning LLC and ask.
With more than 55 years of experience in the industry, Alec is always happy to share practical advice based on real-world experience.
Call Alec’s Carpet & Upholstery Cleaning at 781-871-1415.