I presume Paul, that by woven backed you mean a tufted carpet, sometimes also refered to as secondary or hessian backed. In this case, the reply I would give is the same as Mark's.
If, however, you are refering to a carpet of woven construction, then the answer is quite different. For these carpets, we are normally talking about Axminster and Wiltons. These carpets will shrink if care is not taken. This care, apart from having a good cleaning technique, is primarily down to the pre-inspection. If, say, the gripper under a radiator is not very secure, the carpet's shrinkage potential will find this weak point and pull away. This will leave a ruck in the carpet. The fitting will need to be made good and the carpet re-stretched.
In this type of situation, unless a safety hazard, I would normally advise leaving the carpet as is for about a week prior to rectification. To my customers, I liken this to laundering a pair of cotton trousers/jeans. After laundering, the jeans will be tight for a short while, but after some use, the fibres and yarns relax to give a better fit. Likewise with a carpet. The refit is then easier to perform and will lay better.
Safe and happy cleaning:)
Ken
