What Is Lath and Plaster?
Written by James Walker · Last reviewed 16 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.
Lath and plaster is the traditional way walls and ceilings were built before plasterboard, thin timber strips nailed across the structure, with plaster pushed through the gaps to form a key behind them.
Why it affects a quote
It is fragile and unpredictable. It can look completely sound and come away in sheets once disturbed.
That makes almost any work touching it, rewiring, plumbing, plastering, removing a ceiling, harder to price in advance. A quote that assumes the existing surfaces are fine is a quote that will change.
Repair or replace
Repairing keeps the original material and is appropriate on period and listed properties, where replacing with plasterboard may not be permitted and would lose historic fabric.
Replacing with plasterboard is faster and cheaper, and it is what most modern trades will propose. On an ordinary older house that is often fine; on something listed it may not be allowed.
Ceilings especially
Lath and plaster ceilings fail by losing their key, the plaster behind the laths crumbles and the ceiling sags or comes down. If a ceiling is bowing, that is what is happening, and it is worth acting on.
How it works
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