Underlay

Underlay is vital for a new carpet to sit properly and wear evenly. It improves the feel of the carpet underfoot and helps with that luxury feel. It increases heat and  sound insulation and can therefore reduce energy costs. Underlay also reduces pile compression which allows a carpet to retain a good appearance for a longer period of time and can increase the life of your carpet by up to 40%.

Carpets are installed on a wide variety of underlays and whilst we know that in the majority of cases an acceptable performance of carpet and underlay may be achieved, careful choice of underlay can actually enhance the performance of the carpet. We acknowledge that there is a balance to be achieved between providing the right underfoot comfort and the right support to the carpet and from our experience and evaluation of various underlays we would make the following points.

Benefits of Firmer underlays

• These give added protection to the carpet against the hard sub-floor during normal walking.
• Indentations from furniture will be less severe where the carpet is fitted on a firm underlay.
• Firmer underlays will prevent excessive vertical movement and stretching of the carpet in use and will therefore help to prevent rucking problems.

Comments on Softer underlays

• Soft, low density underlays do not give adequate support in heavy wear areas as the carpet pile is effectively squashed against the sub-floor, accelerating wear and appearance changes.
• A softer product will collapse under the pressure and allow the carpet backing to be distorted, preventing good recovery and making indentations more severe.
• Thicker, softer products have been seen to create dimensional stability problems in some installations where the carpet has stretched due to the excessive vertical movement as the underlay is compressed during normal use. This can cause particular problems on seams.

In our experience it is false economy to fit new carpet over old or softer, cheaper underlay. As already mentioned carpet needs to have as firm a support as possible in order to achieve its maximum performance. An old flattened or new soft underlay will not be capable of providing adequate support to the carpet.

Welwyn Design Leisure’s Preferred types of underlay

1. Good quality hair felts minimum weight 42oz per square yard
2. Firm crumb rubber underlays or high density supportive foam are also recommended. Generally we prefer underlays which are not too thick, we suggest a maximum thickness of 8mm
3. Felt/rubber combinations in the form of a sandwich are also recommended as these combine the support of the felt with a softer “bouncier” feel during walking

Thick, softer foam with holes or egg box or waffle type backings and lightweight felts are not recommended.

Choice of underlay for Stairs

The choice of underlay on stairs is particularly important and, again, firmer products are needed to give a good cushion and support the carpet. Felt or felt combination products help to “round out” the stair nosing preventing premature wear and will at the same time give a better more rounded appearance to each stair.