Ventilation and draughtproofing a listed building

While draughtproofing can be worthwhile in some older dwellings, it can lead to increased moisture levels and cause serious problems with dampness in others. Mould growth and rot damage can occur in a building that has had a stable ventilation rate for hundreds of years.

Typically, moisture from the walls and ground floors of an historic building evaporates into the structure itself. In these cases, heating and adequate ventilation allow the moisture to escape: this is how historic homes have survived with dry and healthy rooms.

Some of the case studies included in this guide show different ways of resolving this issue. Specialist advice is available (see also SPAB information sheet No. 4, see page 2 for contact information). An air-pressure test can be used to assess the property’s airtightness before and after any changes to draughtproofing, if appropriate.