Cavity Walls, Damp-Proof Courses and Waterproofing: A South African Detailing Guide
Guide Type: Technical guide
Understand cavity walls, damp-proof courses and waterproofing as coordinated wall details, including openings, flashings, ground levels and maintenance.
Quick answer
Moisture control depends on a continuous set of wall and roof details. A cavity, damp-proof course, flashings, weep paths, ground levels and external drainage must be resolved together; adding a product alone does not cure a poor junction.
How to compare the options
| Option | Best suited to | Include in the allowance |
|---|---|---|
| Cavity-wall detail | External walls where the design calls for a cavity and moisture-management strategy. | Wall ties, cavity control, insulation where specified, openings and flashings. |
| Below-ground or wet-area protection | Walls or junctions exposed to ground moisture or wet conditions. | Substrate preparation, compatible membrane, protection, drainage and termination details. |
Cost and planning checklist
- Show every threshold, sill, parapet and roof-wall junction on the drawings.
- Keep finished external levels and drainage consistent with the wall detail.
- Use compatible systems and follow the selected product installation requirements.
Use the estimator
Build an early, region-aware allowance in the Price Your Build free estimator. It is a feasibility tool, not a supplier quotation, final design or professional certification.
Related Building Glossary guides
Frequently asked questions
Does a cavity remove the need for good detailing?
No. The junctions and continuity of moisture-management details remain critical.
Can waterproofing be specified after plaster?
Some repairs are possible, but correct early detailing is usually more reliable and economical.
Important
Confirm the final product, scope, installation method, drawings, approvals and professional requirements for the specific site before committing to work.
Source to check
National Building Regulations framework: www.gov.za/documents/national-building-regulations-and-building-standards-act-16-apr-2015-1302