21/05/2026
"Just open a window more." "Get a dehumidifier." "Keep the heating on low."
These are the three pieces of advice that get repeated constantly, by managing agents, by contractors, sometimes even by surveyors. And for condensation, they're partially right.
But if moisture is coming through the fabric of the building, through a failed DPC, through cracked render, through a compromised roof junction, ventilation does nothing except temporarily reduce the humidity of the air inside the room.
The water is still coming in. You've just made it slightly less visible.
Here's the distinction that matters: condensation is caused by moisture produced inside the building. Penetrating and rising damp are caused by moisture entering from outside. They look similar. They behave completely differently. They need completely different solutions.
If the advice you've received doesn't start with identifying which one you're dealing with, it's not a solution. It's maintenance.
Share this if you've ever been on the receiving end of "just ventilate more." And if you're not sure which type of damp you're dealing with, drop a comment. Happy to help you work it out.