The existing corrugated roof had reached the point where weathering and local defects required a coordinated refurbishment strategy. Immediate removal and replacement would have created significant disruption and waste, so the selected route focused on retaining the roof and restoring continuity across its weak points.
The challenge was not simply the surface.
The visible roof area was only one part of the problem. Corrugated sheets create a network of laps, fixings, profile changes and junctions. Local gaps and irregular voids also had to be stabilised before a continuous waterproofing layer could be formed.
Applying a liquid coating directly over unresolved defects would only conceal the weak points. The refurbishment therefore started with the geometry and movement of the existing roof, not with the final finish.
Retain
Keep the existing corrugated sheets in place and avoid unnecessary strip-out.
Resolve
Treat gaps, connections, overlaps and movement-sensitive details individually.
Protect
Connect the repaired details into one continuous liquid-applied finish.
Repair the weak points before coating the field.
Five materials performed five different functions. The system was not based on one product doing everything; it was built by matching each material to the detail it was intended to resolve.
FOME FLEX 7 DOORS & WINDOWS
Flexible, low-expansion PU foam used to fill larger gaps and irregular voids. Once cured, it was trimmed and protected within the subsequent waterproofing detail.
HYDRO FLEX R-38
A permanently elastic waterproofing compound used to treat local connections, sheet junctions and overlaps where a flexible repair was required.
BC SEAL BAND
A cold-applied self-adhesive butyl band with a non-woven facing, used to bridge and reinforce selected joints and movement-sensitive transitions.
WINKLER BASE I
The first treatment stage applied to the prepared fibre-cement surface. BASE I provides biocidal action and an adhesion-promoting interface before the subsequent liquid-applied membrane.
WINKLER ONE VERTICAL
The thixotropic liquid-applied waterproofing layer used across the corrugated profile and repaired details to form the final continuous protective finish.
Filling a void is not the same as waterproofing it. Reinforcing a joint is not the same as priming the field. Each layer had a defined role, and the final membrane connected those individual repairs into one continuous system.
BASE I is more than a generic adhesion primer: Winkler identifies it as the biocidal primer and first treatment stage within the certified WINCOAT asbestos-cement encapsulation cycle. The dedicated encapsulating function in that certified cycle is provided by the subsequent VISTA INCAPSULANTE layer. On this project, BASE I was retained, while the reference H2O waterproofing finish was changed to the ONE system, using ONE Vertical. This records the build-up actually used on the roof; it should not be read as the standard certified WINCOAT cycle.
From local repairs to system continuity.
- 01Condition review and repair mapping
The existing roof profile, joints, laps and irregular openings were reviewed so that local repairs could be defined before full-surface application.
- 02Void filling and local sealing
Larger voids were filled and shaped with FOME FLEX 7. Connections, sheet junctions and overlaps requiring flexible local treatment were addressed with HYDRO FLEX R-38.
- 03Reinforcement of critical details
Selected joints and transitions were bridged with BC SEAL BAND to maintain continuity across areas where movement and changes in geometry concentrated risk.
- 04Biocidal priming and first substrate treatment
Winkler BASE I was applied as the first treatment stage, providing biocidal action and the adhesion-promoting interface between the prepared fibre-cement surface and the subsequent liquid-applied membrane.
- 05Continuous liquid-applied protection
Winkler ONE Vertical was applied across the primed corrugated surface and completed details, creating the final protective waterproofing layer.
The outcome.
The completed work transformed a weathered corrugated roof into a visually continuous, protected surface while retaining the existing sheets. The repair-led approach reduced disruption and avoided the immediate waste associated with full roof replacement.
Most importantly, the strategy did not rely on the final coating to disguise defects. The details were treated as part of the waterproofing system before the main surface was completed.
Refurbishment is not simply coating an old roof.
It is deciding what can remain, what must be repaired and how every local treatment becomes part of one continuous system.
Retention does not remove the asbestos-management obligation.
This case study describes a project-specific waterproofing refurbishment, not an asbestos work method or a claim of compliance with the certified WINCOAT encapsulation cycle. Any work involving asbestos-containing materials must be assessed before work begins and carried out by competent persons under the applicable asbestos, access and work-at-height controls. The retained roof remains an asbestos-containing material and must continue to be identified and managed accordingly.
TECHNICAL REFERENCES
WinklerFibre-cement roof coating procedure · BASE I↗WinklerONE Vertical↗WinklerBC Seal Band↗QuiadsaHydro Flex R-38↗FOME FLEX7 Doors & Windows↗Health and Safety AuthorityACM management guidance↗