Understanding carpet construction in order to correctly dry it after a house flood is first and foremost. Water damage technicians are rarely interested in drying the portion of the carpet you can see and feel known as the pile. Technicians are much more interested in drying the backing.
Carpet backing consists of two layers, the primary and secondary. The secondary backing is what gives carpet its shape and ruggedness. It is the secondary that is stretched and tucked during installation.
The primary is the part of the carpet the pile is woven into. The primary is glued to the secondary, it is this adhesive that breaks down during a water damage. This causes de-lamination. De-lamination is he reason water damage technicians place their fans under the carpet and are quick to remove any wet pad.
When carpet de-lamination occurs, it is next to impossible to re-stretch the carpet back without wrinkles forming in the carpet.