How Long Does Carpet Underlay Last?

Look beneath the carpet

Condition matters more than a birthday.

There is no single lifespan that applies to every carpet underlay. Its construction, use and condition all matter. A surface that still looks tidy does not tell you how well the underlay beneath it is supporting the carpet.

When replacing carpet, plan to review the underlay too. Manufacturer Interfloor advises replacing old underlay with new carpet because worn underlay may no longer provide the support and comfort the new covering needs.

Before reusing what is there

Ask for an inspection.

Tell the fitter about uneven comfort, previous leaks or areas that feel different underfoot. Once the old carpet is lifted, the underlay and supporting floor can be assessed. Do not assume an existing layer is suitable simply because it is already in place.

Check the new carpet’s warranty and installation requirements before considering reuse. Cormar, for example, states in its care and warranty guidance that fitting new carpet on old underlay affects its wear warranty. The terms of your selected product are the ones that apply.

Choose the whole system

Softness is only one part of the choice.

Discuss the room, stair use where relevant and the carpet manufacturer’s requirements. If you have underfloor heating, compare the combined thermal resistance of carpet and underlay with the heating specification; our underfloor-heating guide explains the questions to ask.

Include the underlay by name in your flooring quotation, together with the agreed preparation and fitting work. That makes comparisons clearer and helps you understand the complete installation.

Further reading

Sources and useful next steps.

Interfloor: why underlay matters ↗

Cormar: carpet care and warranty guidance ↗

Guidance reviewed 12 October 2026. Follow the instructions for your own carpet and installation. Manufacturer references do not confirm availability of a particular range.

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