Draughtproof the building#
If you draughtproof your building, be careful not to block up any intentional ventilation, because this could make it damp. It takes a careful professional assessment to understand whether and how intentional ventilation can be reduced.
We have a separate card about windows because that’s often a more involved job.
On external doors or ones between rooms at very different temperatures, think about the gap at the bottom, any letterbox, the keyhole, and gaps around the door. You may not be able to draughtproof fire doors or some doors in listed buildings.
Chimneys can have their airflow reduced with a chimney balloon, chimney cap, or a board covering the hearth, but they do need some airflow to avoid damp.
Loft hatches, the locations of previous extractor fans, and gaps around pipework often get overlooked. Gaps in floorboards and under skirting boards can also be worth addressing.
Some professionals can identify the most important areas to draughtproof using thermal imaging. It’s also possible to get an airtightness test to find out whether your building in unexpectedly leaky, although this does not identify where the losses are. It’s possible to get a sense of the effects of obvious gaps by checking what they do to a candle flame the building is heated and there’s gentle air movement outside, but it’s easier and safer to do this with a smoke pen.