Using the correct underlay is paramount to the longevity of your carpet.
Rugs on carpeted (or wall to wall) floors can move or creep about which is both irritating and can cause damage to your rug. The rug can rise into a crease which is then walked upon as it is the highest point of the flooring, we often see rugs worn in 'ridges' which is an obvious identifier for a rug not sitting flat.
On a polished wooden floor, the rug can become a very dangerous slip hazard, so we would always supply an underlay suitable for the type of wood you have. Many older underlays used to damage wooden floors by in fact gripping or sticking to the wax on the surface which would be stripped off when the underlay is moved. Modern techniques and materials have created some wonderful products which are both very good at their primary purpose but will cause no damage to their surroundings at all.
Stone floors can be a source of wear to a carpet if for example the stones are not laid smooth, old flagstone floors for example can have some very obvious ridges between adjacent stones between the mortar. This will cause a rug to wear prematurely, and can be overcome by using a slightly thicker stiffer underlay which changes the abrupt change in height to a far smoother curve, hence stopping the wear lines in their tracks.
Once correctly laid an underlay will be good for at least ten years and we carry the full range of underlays for each floor surface.
Underlay is £18 sq/m