The main cause of carpet shrinkage resulting from carpet washing in the past was the prolonged exposure of the flooring to liquid. Some businesses didn't realise the importance of drying the carpet after washing.
When carpets were made of lots of natural fibres, shrinking was a major concern. Today most carpets are made of synthetic materials, reducing the risk of shrinking to almost nothing. It's always a good idea to know your carpet type and the manufacturer's instructions for it.
It's true that in the past there was a problem with carpets shrinking after cleaning. This was primarily because the carpet was "over wetted" by the carpet cleaner.
Majority of modern carpets are built either partially or, often, entirely, from ‘composite' or synthetic fibres. These have specially-developed qualities which deliberately prevent shrinkage in a way which natural, untreated fibres of the past were unable to match. Synthetic carpet fibres and backing are impervious to water.
Are you concerned that in striving to achieve a glorious, gleaming carpet you may end up doing more harm than good? Worried that your carpet might even shrink?
When using your carpet washer, to avoid saturating your carpet you should use a maximum of 4 ‘wet' strokes for each area that you are cleaning. Always alternate ‘wet' strokes with ‘dry' strokes and finish by passing several more ‘dry' strokes over the area.
To collect the largest quantity of dirty water possible, and to minimise the subsequent drying time of your carpet, try to push and pull your unit at about half the speed you would an upright vacuum cleaner on the ‘dry' strokes. Steady, careful application also gives the best cleaning results, ensuring stubborn dirt and stains are removed. It's a real life example where the tortoise beats the hare.
Of course, that's not to say common sense shouldn't play a part too. Always test your carpet washer in a discreet area when first operating it, if nothing more than to get a feel for how it works. If you have lingering concerns, any reputable flooring manufacturer will be able to provide advice and guidelines about the tolerances and suitability for washing of your specific type of carpet.
One thing that could cause minimal shrinkage would be an overly wet carpet after your technician is finished cleaning. Reputable companies and technicians don't allow this to happen. Even so, it's a good idea to check your carpet's wetness before the tech leaves your home. Express concerns if you have them. And be sure to hire a reputable company to clean your carpets.
Bottom Line: For most carpets, the risk of shrinking is almost nothing. Hiring a reputable company makes all the difference in your satisfaction.
Using the current technology this is no longer a problem. We have special jets that restrict the amount of water we spray into the carpet ensuring that the backing of the carpet remains dry. This ensures that the carpet stays in its original shape and size. We also dry the carpet as part of the process of removing the soil and stains from your carpet.