If you’ve had your previous underlay down for a number of years, it is time to replace it.
For the best results a new and firm underlay should be laid on a clean dry floor. The underlay should then be fixed by tacks or tape, with joins butted together. As woven secondary backed carpets need to be stretched evenly across the room from wall to wall, this will stop movement of the underlay when the carpet is laid. The carpet should be stretched evenly and held on a carpet gripper which has been pre-nailed to the perimeter of the room. This will ensure the pile of the carpet will sit upright, giving the best resilience to foot traffic. This also helps to reduce the wear of your carpet.