Back in June Roger Curtis from Historic Environment Scotland delivered two CPD sessions on Damp in older and historic buildings. Roger looked closer at the occurrence of damp in older buildings, and the contributing causes, including how some remedial measures can make things worse.
Additionally, Roger described the changing weather conditions in Scotland and how that is having an impact on older buildings. Considering what was done in the past, with the external envelope, what these details can teach us now, and what architects and designers need to think about to prevent damage to facades and internal problems.
Here are 12 points we learned from these presentations:
1. Damp is just a term for where moisture collects.
2. When you see salty residue on the outside of an older building, this could be the lime binder separating from the sand it binds… ask the question, what is keeping the wall together if there is no binder?
3. Moss feeds on water if you see moss, what is it drinking?
4. Older buildings like to breathe, chimneys were the buildings air passage, if you block those up, make sure you use the correct materials to allow the buildings to breathe, this will stop vapour issues i.e. condensation.
5. Ivy isn’t always bad. If you manage the ivy correctly, it can drink any pooling water which could normally be saturating a building, but make sure you manage the ivy correctly!
6. Make sure you keep all the gutters clean and healthy; a lot of issues could be solved by this simple regular maintenance.
7. Since the 1940s, precipitation has increased by 45% in Argyll, so what is suitable to damp proof your building in Edinburgh, might not be the same for a building in Oban.
8. Think about detailing, drip detailing and channel chute keep excess water off your building.
9. Lime render allows vapour exchange, unlike a cracked hard render which can draw water into a building.
10. Chimney covers keep the rain out of chimneys, simple but true, also invest in some kind of mesh to stop birds moving in.
11. Don’t tarmac or concrete directly up the sidewall of your building, it needs breathing space.
12. Sometimes a simple solution such as digging the ground a little as 300mm can help solve a damp issue, make sure soil hasn’t grown over the air vents over the years.