Module 3 · Types of Damp in Detail
3.3 Rising Damp: What It Is and What It Isn't
9 min read
No topic in damp surveying carries more received wisdom and less evidence. Rising damp is real, and it does occur — but it is diagnosed far more often than it happens, and the cost of getting it wrong is a client paying four figures for injection work that does nothing. This lesson sets a proper evidential bar.
Learning objectives
By the end of this lesson you will be able to:
- State the three conditions genuine rising damp requires.
- Identify the diagnostic signature and the height limit that constrains it.
- Distinguish true rising damp from bridging, leaks and hygroscopic salts.
- Apply an appropriate standard of evidence before making the claim.
Key terms
- Capillary rise
- Groundwater drawn up through the fine pores of masonry and mortar by surface tension.
- Damp-proof course (DPC)
- The horizontal barrier interrupting that rise — slate, bitumen, engineering brick, or an injected chemical cream.
- Tide mark
- The horizontal line where capillary rise balances against evaporation from the wall face.
- Nitrates and chlorides
- Groundwater salts deposited at the evaporation line. Hygroscopic, so they hold moisture from the air afterwards.
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.