On this page
Waterproofing failures are rarely the fault of a single product. After years of rehabilitating roofs, tanks, basements, and decks across the UAE, the same root causes appear again and again. Recognising them at the design or tender stage is the most effective way to avoid them.
Eight recurring root causes
1. Inadequate surface preparation
The most common failure mode is delamination caused by insufficient mechanical preparation of the substrate. Sweeping a substrate is not preparation. Grinding, shot-blasting, or scarifying to ICRI CSP 3–5 with primer is the minimum standard.
2. Wrong system selection
A rigid cementitious coating on a substrate with thermal movement will crack. An aromatic polyurea left exposed will chalk. Specification needs to match exposure.
3. Detailing failures
Upstands, drains, penetrations, and expansion joints fail before flat areas. Pre-detailing with reinforcement fabric is essential.
4. Insufficient film thickness
Applying the system at less than specified DFT leaves pinholes and reduces service life. Continuous WFT monitoring during spray prevents this.
5. Application outside environmental window
Applying when substrate temperature is within 3 °C of dew point causes condensation under the film. UAE coastal summer mornings are particularly vulnerable.
6. Substrate moisture above limits
Most polymeric membranes require substrate moisture below 4–5%. Applying over a wet slab guarantees blistering and disbondment.
7. Mechanical damage after install
Membranes damaged by follow-on trades, dropped tools, or unprotected traffic are a primary source of post-handover leaks. A protection layer or screed is mandatory under any trafficked or screeded build-up.
8. No acceptance testing
Systems accepted without flood test, DFT verification, and pull-off testing inevitably produce post-handover claims.
Rehabilitation strategy
When a system fails, the response should be diagnosis-led, not product-led. Identify the root cause, decide whether to over-coat or strip, then specify a replacement system matched to the exposure. Rehabilitation without diagnosis tends to repeat the same failure.
