Module 3 · Types of Damp in Detail
3.2 Penetrating Damp in Detail
8 min read
Penetrating damp is the most satisfying mechanism to diagnose because the cause is usually findable, visible and fixable. The skill is knowing where to look — and understanding that the entry point is frequently well away from, and above, the patch you were called out to see.
Learning objectives
By the end of this lesson you will be able to:
- List the external defects that most commonly admit water.
- Explain how exposure, elevation and weather direction change the risk.
- Trace an internal symptom back to a plausible entry point.
- Distinguish penetrating damp from condensation and leaks by behaviour.
Key terms
- Driving rain
- Rain given a horizontal component by wind, so it strikes walls rather than falling past them.
- Exposure
- How much weather an elevation receives, driven by orientation, height, and shelter from other buildings and terrain.
- Flashing
- A weatherproof detail sealing a junction, typically where a roof meets a wall or a chimney.
- Spalling
- The face of a brick breaking away, usually from frost action on saturated masonry, exposing a more absorbent surface.
Free — enrol to continue
Read the rest of Types of Damp in Detail
Module 1 is open to everyone. The remaining six modules — building science, each damp mechanism in depth, meters and thermal imaging, the full inspection method, and report writing — are free too. We just ask for an email so you can pick up where you left off, and so we can send your certificate when you finish.