Module 7 · Proportionate Remediation
7.3 Chemical Damp-Proof Courses
10 min read
No intervention in British damp practice is more argued about. One position holds that rising damp is largely a myth and injected courses are a product in search of a problem; another that it is a real mechanism with a proven remedy. Both positions contain something true and both are usually stated too strongly. A practitioner needs to be able to set out what the evidence actually supports, specify one where it is indicated, and advise against one where it is not — without either enthusiasm or reflex.
Learning objectives
By the end of this lesson you will be able to:
- Explain what an injected course does and the conditions it requires to work.
- State the conditions under which it is genuinely indicated.
- Identify the far more common cases where it is not.
- Advise on an existing installation that has been blamed for a persisting problem.
Key terms
- Injected damp-proof course
- A water-repellent formulation introduced into a mortar course to line the pore structure, so capillary transport across that plane is impeded.
- Pore lining
- The mechanism: the treatment does not fill the wall, it makes the pore surfaces water-repellent so capillary suction cannot act.
- Replastering specification
- The plaster system installed alongside an injected course, which addresses the salt-contaminated plaster. Frequently the part that actually resolves the symptom.
- Bridging
- Any path around the treated plane — high ground, a render coat, debris, an abutting structure. Defeats the treatment completely.
Read the rest of Proportionate Remediation
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