What Is a Defects Liability Period?
Written by James Walker · Last reviewed 15 August 2026
James Walker has 2 degrees in construction (BSc (Hons) Building Surveying · MSc Environmental Design of Buildings) and an extensive background in issue resolution, resolving over £4 billion of consumer issues.
A defects liability period is a defined window after the work is completed during which the builder remains responsible for returning to fix faults that appear.
Why it exists
Some faults only show up in use. A slow leak at a joint, plaster cracking as it dries, a floor lifting through a change of season, a boiler fault under real load.
The defects period recognises that "finished" and "proven" are not the same thing.
How long it lasts
It varies by agreement. Where nothing is stated, you still have legal rights, but a defined period makes expectations clearer on both sides.
How it relates to the retention
They work together. A retention held until the end of the defects period gives the builder a practical reason to return. Released at practical completion, it does not.
This is the argument for holding the final 10% beyond the last day on site rather than paying on the day the scaffolding comes down.
What it does not cover
Wear and tear, damage you caused, or things you have changed your mind about. It covers defects, work that was not right.
How it works
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