Water has damaged your carpets. Maybe you had a toilet leak, maybe your water heater burst, maybe your kid left the faucet running in the sink for hours.
What should you do to dry your wet carpet to minimize damage to your carpet and pad?
First of all, there is some general information about carpets you should know that applies to all the myths.
General Information about Water and Carpets
Residential carpet usually has a pad underneath it. The pad can be anywhere from 1/4 inch to almost an inch thick. The pad provides cushioning and gives your carpet that comfortable, soft feel when you walk on it.
Commercial carpet in offices and stores generally does not have pad underneath it.
Carpet pad absorbs water like a sponge: The problem with pad under a carpet is that it is a sponge and can hold many times it's own weight in water.
Pad is designed to cushion your feet, so it is spongy by nature and will soak up water like the cleaning sponge in your kitchen sink.
Carpet does not stop or hold much water:
Although your carpet may feel very solid under your feet, it offers very little resistance to water passing through it.
Carpet is actually like a sieve to water. A typical carpet will not hold more than a few ounces of water per square foot of carpet before it is planned. After these initial few ounces of water have entered the carpet, any further water filters straight through the carpet and into the pad.
Water likes to travel: Water does not stay put, it is always on the move. The rule to remember is "Wet goes to Dry". Water will automatically move towards a dry building material.
Water at the center of a room will flow through the carpet and across the pad to the walls. It will migrate to the edges of the room in a matter of minutes or hours depending on how much water was spilled.
When you touch the carpet at the edge of the room, it may not even feel damp, but the pad could be seated. This can be seen using an infrared camera. An infrared (or Thermal Imaging) camera is useful in finding the real area that the water has damaged, even if you can not see or feel it.
In general I would say that the actual wet area in any flood (found with professional water damage meters) is about twice the size of what the home owner reports.
An infrared camera will show how water travels under the carpet through the pad. Even in a 'small' flood, water can migrate through walls and end up 2 rooms away within 12 hours.
Bearing the information above in mind, here are some common myths about wet carpets and how to dry wet carpets
Myth # 1. The carpet will dry by itself
This is actually true, just like it is true that you could win the lottery with one ticket.
Yes, the carpet will actually dry by itself. However, will it smell bad or have mold on it by the time it is dry? What other damage will occur while the carpet dries by itself?
Unless you live in someplace like Arizona or the desert where you have high temperature and low humidity, there is VERY little chance that the carpet and pad will dry before mold starts growing or bacteria start creating that wet carpet, damp smell. Typically you have about 72 hours to dry wet building materials before they start growing mold.
Even if the carpet itself dries, does that mean the pad is dry? There is very little chance that the pad is dry. The pad holds more moisture than carpet and is prevented from easily releasing the moisture due to the carpet above it and the sub-floor below it. So even if your carpet is dry, the pad is probably not dry.
Which brings us to another point. What about the wet sub-floor? Remember that carpet is like a sieve, and the carpet will pass water down to the pad very quickly. A fitted pad can then water into the sub-floor.
Sub-floors are usually either wood or concrete.
Concrete sub floors are sponges too, except they are very slow sponges. They absorb water surprisingly quickly, but release it very slowly. So even if the carpet and pad are discharged quickly, the concrete sub-floor could still release moisture for weeks.
Wood sub-floors hold water too. If they're made of chip-board / particle board / press-board (small chips of wood held together with glue) and they are wet for more than a few hours they absorb water, expand, and lose their structural integrity.
When wet particle board dries it has almost no strength and you will find yourself stepping through your floor if you're not careful.
Plywood or OSB (Oriented Strand Board) are much more hardy choices for a sub-floor than particle board. If they get wet, you can dry them, as long as they have not been sitting wet for long enough to warp. This falls loosely under the 72 hour rule. Another concern is dry rot which is a bacterial deterioration that takes 21 days to manifest at lower moisture levels.
Determining whether the sub-floor is wet or not can only reliably be done with a penetrating moisture meter. Different building materials have different acceptable levels of moisture, so you use the meter to tell you if the material is acceptably dry or not.
Depending on the region you live in, plywood is dry at around 20% Equivalent Moisture Content (EMC). In as little as 4 days, mold can start growing on wet plywood if not discharged correctly.
So, we know that the carpet and pad are unfortunately to dry quickly enough by themselves. But even if they did, is that all you have to concern yourself with when your carpets are wet? No, it's not.
Like I said, WET goes to DRY. What this means is the water keeps spreading outwards from the source.
On one flooded carpet job we did, the carpet first got wet about 12 hours before we arrived. During that time the home owner used her wet vac to suck up as much water as possible from the wet carpet – about 100 gallons.
She just wanted us to dry her carpets. However, using the infrared camera and moisture meters, we found that her walls were wet, in some places to almost 12 "above the carpet.
Wet drywall, is that a problem?
The problem with wet drywall is the usual 72 hour problem.
In as little as 72 hours mold can start growing on that wet dry wall. Mold especially likes dark, warm places with no airflow. That describes the wall cavity – the perfect place for mold to grow.
So that's the problem – wet carpet creates wet drywall which can create mold. Below is a picture of a wall after water had been standing for a long time.
To summarize. Yes, the carpet will actually dry by itself. But you'll more than likely have mold and smells by the time it is dry, and then you'll be ripping walls and carpet out to fix the problem
Myth # 2. You have to remove the wet pad underneath your carpet
There is a myth that you can not remove water from a wet pad, even with commercial extraction equipment. People who say this are talking about the standard carpet cleaning 'wand' shown on the right. It is what is commonly used for clean carpets. It sprays hot water onto the carpet and then sucks it back up again.
The wand is designed to pull water out of the carpet fibers, not the pad and it does a good job at that. So if you have water damage on commercial carpet without a pad, the wand is a good tool to use.
However, on residential carpet with a pad, it extracts almost none of the water from the pad.
So how do you get water out of the pad so you do not have to remove and discard the pad?
There are a number of new commercial extraction tools that will remove water from the pad. Our favorite is the FlashXtractor. It is a wonderful piece of equipment, probably my favorite tool. (We have no affiliation with the makers of this tool, and receive no compensation for mentioning it)
The FlashXtractor will pull buckets of water out a carpet that has been wand extracted to death!
Before tools like the FlashXtractor came out, there was a technique called "floating the carpet" which was used to dry carpet and pad due to the poor job the wand did of extracting water from the pad.
To float a carpet, you pull up a corner of the carpet and stick an air mover or carpet fan under the carpet to blow air under the carpet and onto the pad. While this method still works it is slower, less effective, and often stretches the carpet so that it does not fit properly when restretched.
Floating the carpet is an old school technique that is unnecessary if you have the right tools, ie a deep extraction tool such as the FlashXtractor.
To complicate matters, bear this in mind. While you can dry wet pad, it does not always mean you should.
If you have contaminated water in the pad you can dry it, but you will be leaving at least some contamination in the pad and over time, it will start to stink and rot. In contaminated water situations you will have to remove the pad because you can not effectively decontaminate it while it is underneath the carpet. In the water restoration industry, contaminated water is called Category 2 (gray water) or Category 3 (black water).
Myth # 3. You can not dry a wet pad under a carpet
The truth to this myth is the same as for the question above. Basically, you can dry a wet pad, even without floating that carpet, but that does not mean you always should. See the answer above for details.
Myth # 4. You have to lift the carpet and 'float' it using blowers
The answer to this question is in the answer to question 2 above. To summarize, you do not have to float carpet if you have a deep extraction tool and know how to use it.
Myth # 5. You have to remove and discard wet carpet.
If you have a black water situation (Category 3 water – contaminated water such as sewage, toilet leak or rising ground water), according to the industry standard IICRC S500, you have to discard the carpet. I believe this is because there is no EPA registered disinfectant for carpet.
However, if you have Category 2 water (gray water such as washing machine waste water, shower runoff, etc) you have to discard the pad, but you can clean the carpet and keep it.
Category 1 water (clean water – toilet supply line, fridge ice maker, etc), and it has not been sitting for more than 48 hours, then you can extract the water and keep the carpet and pad.
The other reason water damage restoration technicians sometimes believe they should discard wet carpet is because the backing of the carpet will de-laminate when it is dried. The backing is the lattice webbing on the back of the carpet that holds the carpet fibers together. It is glued on. If it gets wet and lasts wet for a long time it can separate from the carpet fibers and start to disintegrate.
How long is a long time? It's hard to predict – depends on the carpet, the temperature, how wet it was, etc. Normally by the time the carpet de-laminates you've got a black water situation anyway, so the carpet has to go.
Myth # 6. Professional Carpet Cleaning will dry your carpet and pad
No. Not unless they use a deep extraction tool that is specifically designed to remove water from the pad. A regular carpet cleaning wall will not remove significant water from the carpet pad.
Myth # 7. To remove the wet carpet smell, you should have it professionally cleaned.
Yes, with a 'mostly' attached to it. The carpet cleaning machines and methods available to most home owners are not very effective. Compared to commercial carpet cleaning equipment, the carpet cleaning machines you rent from the local supermarket are like a moped is to a Harley. They're the same thing, but not really.
Getting anything other than a light smell out of a carpet requires the high pressure and suction of a commercial machine. It also requires the expertise of a trained and experienced carpet cleaner. There are many causes and solutions to different smells in a carpet and knowing what to do and when to it requires training and experience.
If baking soda and vacuuming do not work, your best bet is to call an trained and experienced carpet cleaner, preferably one that is also an IICRC certified Odor Control Technician.
Myth # 8. If you dry a flooded carpet, you will not get a moldy wet carpet smell
Depends. If a carpet is discharged quickly and properly there will be no smell. In fact, if anything, there will be less smell because the carpet has effectively been cleaned.
If the carpet and pad are not discharged quickly and correctly you will probably have a problem with lingering musky smells and mold.
See myth # 2 for more details.
Myth # 9. You have to use a truck mount carpet extractor to dry or clean a carpet properly
False. This is an ongoing argument that I do not think will ever be resolved completely. Portable carpet cleaning machines have the advantage of short hose runs while truck mounts have the advantage of high power.
What it brings down to is really the technician holding the wand. A good technician on a bad machine will get a better result than a bad technician on a good machine.
If you've had more than a few gallons of water spilled on your carpet, you're better off calling a professional water damage company to properly dry your home if you can afford it, or if you have insurance. As you leaned above, the problem is that if the carpets and walls are not discharged quickly you could face a mold situation which is much more expensive to fix than drying the carpets.