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Commercial Weatherproofing — Penrose

Gutter membrane coating, flashing replacement, and targeted leak remediation for a commercial property in Penrose, Auckland.

Client TypeCommercial Property Manager
SectorCommercial
Roof TypeFlat membrane + metal
ServicesRepairs & Maintenance
LocationPenrose, Auckland
The Problem

Years of deferred maintenance had taken their toll

The building in Penrose had been experiencing persistent leaks. An inspection identified multiple failure points across the roof system — the kind that develop gradually when small issues go unaddressed.

Ponding Water

Standing water across the flat roof surface indicated poor drainage. Pooled water accelerates membrane degradation.

Failed Sealant & Seams

Cracked sealant at roof seams and exposed fasteners had created multiple water entry points.

Corroded Penetrations

Rusted vent penetrations with failed sealant and degraded membrane surrounds.

Edge & Gutter Deterioration

Corroded eave edges, failed protective coatings, and compromised gutter junctions at the perimeter.

Condition on Inspection

The following photographs were included with our quotation to document the defects requiring remediation.

Aerial view showing ponding water across the flat roof surface
Ponding water across the main roof area
Rusted vent penetration with failed sealant
Severe rust at roof vent penetration
Failed sealant at roof seam joint
Deteriorated sealant and exposed fasteners at roof seam
Missing fastener and surface corrosion on metal roof panel
Missing fastener with seam separation and surface corrosion
Rust and sealant failure at roof eave junction
Rust and compromised sealant at eave–gutter junction
Coating failure and corrosion at roof edge
Failed protective coating and corrosion at roof edge
Membrane separation at parapet wall junction
Membrane pulling away from parapet wall — water ingress risk
Roof membrane delamination at the parapet edge
Membrane delamination exposing the roof deck at perimeter
Gap at roof-to-wall junction with moss growth indicating moisture
Moss and moisture in the roof–wall gap — active water retention
The Solution

Targeted repairs to restore weathertightness

We recommended addressing each failure point directly. The scope targeted the specific defects identified during inspection.

Gutter Membrane Coating

Silicone liquid membrane coating system applied to both gutters with fiberglass reinforcement at dropper outlets and pipe penetrations. Built up identified ponding areas and detailed membrane into all outlets and transition areas.

Apron Flashing Installation

Two new apron flashings installed at the western roof–wall junction, plus a custom-fabricated corner flashing at the internal wall interface. All junctions prepared and integrated with the existing roofing system to direct water away from the building.

Joint Sealing & Fastener Replacement

Up to 15 parapet and apron flashing lap joints riveted and sealed. Approximately 500 replacement roof screws installed across accessible roof areas to restore mechanical fastening integrity.

Membrane Repair at Parapet

Re-sealed the membrane-to-parapet wall junction where water pooling and separation had created a persistent leak path into the building envelope.

Work in Progress

Envelope Roofing technician installing membrane coating
Applying silicone liquid membrane to the gutter system
Technician sealing membrane seams on flat roof
Sealing and reinforcing membrane seams
Flashing and membrane detail work at roof junction
Flashing detail at the roof–wall junction
The Outcome

Weathertight and back in service

All identified defects were remediated to a weathertight standard. The client received photographic documentation of work at each defect location, a marked-up plan showing treated areas, and a maintenance schedule.

Key Result

The roof was brought back to weathertight condition.

The photographs above document the work as it progressed — from the condition found on inspection through to the remediation work carried out by our team. Each defect location was treated, photographed, and recorded.

Site-specific safety plan prepared before work commenced. Service report provided on completion.

Related: East Tāmaki Repairs · Wiri Investigation · Roof Repairs & Maintenance

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