Suffolk Building Conservation Associates

Expert carpenters, craftsman and artisans for specialist historic building conservation and repair

Call: 01284 735057   Email:



The need to breathe


External Links


Old buildings we are told need to breath! What does this mean? Have a look at the following pictures, these are good examples of  buildings that did not breath, be warned!

Damage caused by Cement with polythene sheeting

Clay Lump covered in Cement Render

Damage caused by Cement Render

Damage caused by Death watch Beetle


Pre 1930’s properties are unlikely to have damp proof courses, brick work would almost certainly have been laid using lime as opposed to cement, wall plasters would also have been lime or clay based.

Lime/clay plaster and mortar mixes allow far more movement in the building as compared to cement based, which are extremely hard, and will not allow moisture in the walls/ floor to escape.

Lime/ clay mixes allow moisture to evaporate from internal and external surfaces.

Decoration also needs to be considered carefully. Traditional, external walls would have limewash applied, internal surfaces could also be limewash or distemper or clay based paints.

Sealing the outer skin with non-breathable paints and sealants to repel rainwater ignores how much moisture is generated inside a building by cooking, showers and baths, washing and drying clothes. These well meaning alterations, by preventing the building from "breathing", increase the build-up of moisture in the walls and cause much of the damp found in old houses. 

Stopping water from entering your property  in the first place is perhaps stating the obvious, but consider a dripping gutter running down your wall, it will if not repaired create excessive damp.
So, “The need to breathe”.

If the fabric of your building has materials that will allow moisture to evaporate from all surfaces (rather than hold it in or below the surface, where given time it will rot timber frames etc.), you will be reducing the damp to a level where damage will not occur.

If for example your external walls are not breathing, and moisture in the wall is not being released through evaporation on the external surfaces, in winter when your heating is on, the rising internal temperature will draw moisture to the internal surface and show as damp.

For further reading/ information on this subject, use the links to: -

SPAB (Society for the Protection of Ancient Buildings)
St Edmundsbury Borough Council
Both of these organizations have excellent literature.

And please contact us, if you would like any advice in the conservation/ repair of your wonderful historic old building.