During their time of service carpet cleaners encounter the problem of rippling on carpets. The ripples may appear on a carpet installed over underlay. If the ripples appear only from everyday use, it might be because of the thickness of the underlay or from improper stretching during installation. Another reason might be if the carpet was not laid tightly or hasn’t been acclimatised. Carpets should be left open in the room for 24 hours prior to fitting.
During the cleaning process itself, ripples appear on tufted carpets particularly the ones with a polypropylene. Some moisture is absorbed by the fibres and the rest settles into the backing. The tightly woven fabric does not allow water to pass through easily, so expansion and stretching are caused for a while before the water evaporates. That is why rippling appears as the water has nowhere to go. It is advisable, that carpet cleaner can explain to their customers that this is normal to happen.
Luckily, some manufacturers use different gauge webbing which absorbs the moisture better or lets it into the adhesive. Finally, if the ripples show up before the carpet cleaners start their work, the ripples are most probably caused by the installation or traffic in the area.