Underlay Types

Benefits

Good underlay will...

• Improve underfoot comfort
• Increase appearance retention, reducing flattening
• Absorb the pressure of foot traffic and reduce wear
• Improve thermal insulation and warmth
• Increase sound insulation
• Smooth out sub-floor imperfections
• Last the lifetime of the carpet

Poor or old underlay will...

• Feel hard and unwelcoming
• Reduce carpet life
• Cause wrinkling and premature wear spots
• Cause carpet fibres to break down more quickly
• Not meet British Standards

How thick?
A maximum of 12mm is recommended (working with gripper will be difficult thereafter) but rooms with heavy traffic will need a thinner, denser pad. The combination of thickness and density is all important as a thick underlay with low density may not perform well. Typically, the thicker the underlay, the better quality it will need to be – 11mm is often used for luxury installations with 9mm and 7mm the common domestic thickness.

Types

PU (polyurethane) foam
The markets most popular underlay. Typically made from recycled foam off cuts. The foam provides excellent comfort and performance levels with lots of thickness options and densities – and its light weight helps handling. The product can be re-cycled again after use.

Crumb
Flat and dense, crumb rubber is good for heavy footfall- offering maximum protection but a little less comfort (and very good over stair nosings).

Sponge rubber
Available in flat or waffle patterns in a wide range of weights for different applications. It performs well for comfort and has a durable spring retention.

Combination
A rubber crumb base with a felt top layer offers a good combination of protection, durability and comfort. It also allows carpet with seaming to bed into the top felt.

Felt
This traditional (but environmentally friendly) underlay is made from recycled fibres – wool, jute and synthetic – to create a firm, dense pad with excellent thermal insulation. Still a very popular choice among contractors when stretch fitting woven carpets.

Underfloor heating underlay
Most manufacturers offer specialised products. Underlay and carpet with a combined tog rating up to 2.5 can be used – which means the underlay would normally have a tog rating of 1.0.

Pre-tackified underlay
A self-adhesive single stick underlay in both needlefelt and PU. A removable system for heavy use when comfort is desired.

Laminate underlay
It is always recommended to purchase a good quality underlay with laminate flooring, improving the acoustic performance of the floor and helping the boards float above any imperfections in the sub-surface.