Rainy-season preparation
Roof waterproofing before the rainy season: 8 places owners should check
The aim before the rainy season is not to add material immediately. Use dry weather to inspect drainage, junctions and the existing system, then confirm water flow and ponding after rainfall.
Direct answer
Before the rainy season, clear and photograph drainage routes; inspect parapets, wall-to-roof junctions, cracks, thresholds, equipment bases and the existing waterproofing for debonding, blistering or cracking; then record ponding boundaries and recession times after rain. Widespread system failure, substrate defects or inadequate falls should not be covered by another coat. Compare complete reconstruction with a Polyurea overlay only after site conditions are confirmed.
Editorial and review record
Published2026-06-19
Updated2026-06-19
Content ownerProficient Waterproofing & Engineering Ltd.
Technical reviewProficient Waterproofing Technical Team
This checklist supports preliminary inspection and photographic records. It does not replace a site survey, testing, structural assessment or statutory professional advice. Work at height should only be carried out with suitable safety measures.
Rain inspection checklist
Inspect these 8 locations in sequence.
01
Obstructions at drainage outlets
Remove visible leaves and loose debris, then check the grating, surrounding termination and water entry. Do not push debris into the drainage system.
Suggested recordBefore-and-after photographs, outlet close-up and roof-zone overview
02
Ponding boundary and recession time
Where safe, record the ponding extent and approximate recession time after rain, especially at low points, wall junctions and equipment bases.
Suggested recordSame-angle photographs, capture time and marked ponding boundary
03
Parapet tops and wall-foot terminations
Inspect coping joints, render cracks, corners and waterproofing upstands for separation where different materials meet.
Suggested recordContinuous photographs of coping, wall foot and corners
04
Roof cracks and movement joints
Record crack length, direction and changes, including whether the crack reaches a wall foot, threshold or equipment base.
Suggested recordScale-referenced close-up and overall location photograph
05
Roof access, frame and threshold
Check threshold height, frame joints, canopy and adjacent roof area for a visible route for ponded or wind-driven water.
Suggested recordBoth sides of the threshold, frame and canopy
06
Equipment bases, railings and fixings
Later additions can penetrate or compress the waterproofing. Inspect each base, bolt and surrounding termination.
Suggested recordAll sides of each base, fixing points and adjacent surface
07
Previous repairs, blistering and peeling
Repeated coatings, blisters, hollow areas, chalking or peeling indicate that adhesion and the substrate must be checked.
Suggested recordOverall defect area, close-up and known repair year
08
Drainage route and overflow
Trace water from high points to the outlets and confirm that bases, stored materials or later works do not block the intended route or overflow.
Suggested recordOverview marked with flow direction and obstruction locations
Repair decision
Choose complete reconstruction or a Polyurea overlay from the site conditions.
Use the same two system directions as the home page, checking the existing layers, substrate, moisture and drainage before defining the works.
01 / Full removal
Complete removal and reconstruction of the roof waterproofing system
A high-rise duplex project showing removal of the existing build-up, substrate preparation and the scale of a complete waterproofing reconstruction.
View suitability and limitations
- More suitable when
- The existing waterproofing has widespread failure, debonding or peeling; the substrate needs repair; or drainage falls and junction details must be rebuilt.
- Confirm before work
- Removal limits, substrate repairs, drainage falls, waterproofing build-up, protection or reinstatement, and coordination with rooftop equipment and other trades.
- Main limitation
- The scope and programme are larger. The quotation should clearly state removal, waste disposal, reinstatement, testing and exclusions.
02 / Overlay system
Seamless Polyurea spray system without full removal
Project footage from residential roofs, petrol stations and basements illustrating Polyurea overlay applications. Suitability still depends on substrate, moisture, drainage and existing-layer conditions.
View suitability and limitations
- More suitable when
- The substrate and most of the existing system remain stable, allowing a continuous waterproofing surface to be formed after cleaning, repairs and reinforcement of details.
- Confirm before work
- Adhesion of the existing layers, substrate moisture, material compatibility, drainage falls and termination details.
- Main limitation
- A new coating must not be used to conceal debonding, trapped moisture or unresolved drainage defects.
Further guidance
Open the details needed for further assessment and enquiry preparation.
01 Two-stage check
Inspect in dry weather, then verify after rain
Dry weather is suitable for inspecting cracks, blisters, peeling and terminations. After rain, water flow, ponding boundaries and leakage timing are easier to verify. Use the same camera angles where possible.
Do not approach exposed roof edges when the surface is wet, windy or unprotected. Arrange suitably equipped personnel where access is unsafe.
- 01Four-direction roof overview
- 02Close-ups of all eight positions
- 03Matching before-and-after-rain photographs
- 04Known repair year and method
02 Scope planning
Organise findings into a quotation-ready scope
Label the location, number and approximate extent of each item. The quotation should state substrate work, reinforced details, main waterproofing layer, terminations, protection or reinstatement, inspection and exclusions.
03 Maintenance record
Keep the same photo set for next season
Retain the date, location plan, photographs and treatment method after inspection or completion, so the same details can be compared next rainy season.
A material name does not replace a work scope. If new marks appear, give the engineering team the weather timeline, existing record and new photographs together.
Project evidence
Related residential project records
Related reading
Related roof waterproofing articles
How to assess roof ponding: falls, outlets and waterproofing checks
A roof ponding guide covering recession time, drainage outlets, falls, wall junctions, cracks, equipment bases and existing waterproofing before defining the work scope.
Parapet and wall-foot leakage: cracks, terminations and upstands
A parapet leakage inspection guide covering coping joints, cracks, wall-foot corners, waterproofing upstands, fixings, thresholds and previous repairs.
FAQ
Frequently asked questions
Should the entire roof receive another waterproofing coat before the rainy season?+
Not automatically. Existing adhesion, substrate moisture, drainage falls and details must be checked first. A new coat cannot correct debonding, trapped moisture or drainage defects.
Is clearing the drainage outlet enough?+
It is important but not sufficient. Also inspect the flow route, low-point ponding, wall junctions, thresholds, equipment bases and failed existing layers.
Should owners inspect the roof while it is raining?+
Do not take risks during thunderstorms, strong wind or slippery conditions. Record leakage timing from a safe location and arrange roof inspection after conditions stabilise.
Can photographs replace a site survey?+
They help with initial triage and scope planning, but moisture, hollow areas, concealed junctions, falls and complex water paths usually require site confirmation.
Source record
Sources and further guidance
- 01Buildings Department: Water seepage in buildings
Official guidance on possible causes, owner and occupier responsibilities, coordination with building management and when professional advice may be required.
- 02Roof leakage and repair responsibility guide
Proficient Waterproofing's framework for tracing water entry and checking common areas, exclusive-use areas and deed provisions separately.
- 03Roof waterproofing cost and scope guide
The scope items that should be stated when comparing a Polyurea overlay with complete removal and reconstruction.
Residential enquiry
Need help organising leakage evidence and next steps?
Send an overall roof view, the leakage location and approximate affected area. Our engineering team can identify what should be confirmed during a site survey.