Why thicker is not always better
On a staircase, an over-thick underlay makes the nosing soft and the carpet flexes over the edge — that is exactly where a stair carpet wears out. 8mm is the sensible ceiling on stairs regardless of what is going in the bedrooms.
Over underfloor heating the logic reverses: you want a low-tog underlay so the heat reaches the room instead of being insulated into the slab. We check the combined tog of underlay plus carpet against the system's design figure.
What we include as standard
- New gripper on every fit — reusing old gripper causes ridges and pops
- Damp-proof membrane on ground-floor concrete
- Underlay taped at joints so it cannot shift under the carpet
- Old underlay and gripper uplifted and taken away