Home / Damp Around Chimneys in Oldham
Damp around chimney breasts

Damp Around Chimneys in Oldham

A damp patch beside a chimney breast does not give you one diagnosis. Chimneys bring together roof junctions, masonry and ventilation, all in the same place.

Worn lead flashing around the base of a brick chimney on a tiled roof.
Chimney junctions deserve a close look. Water often gets in where materials meet.

After rain

If the patch darkens after wet weather, the external chimney and its roof junction move up the list. Flashings, soakers, flaunching and open joints should be checked.

Unused chimneys behave differently

Closing a fireplace changes airflow through the flue. If ventilation is poor, moisture can condense inside and salts in old soot can attract moisture. That can produce staining even when the roof is watertight.

One side only

Damp concentrated on one side of the breast can sometimes line up with the weather side or a particular roof junction. That is useful when deciding where to inspect first.

Do not seal everything blindly

Coating internal plaster or external masonry before understanding the source can hide symptoms for a while. The route of moisture still needs dealing with.