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How AJS Environmental prevented leaks and extended the life of a commercial rooftop drainage system.

Flat roofs and podium decks take a beating from the British weather. When drainage outlets start to fail,
small cracks and gaps can quickly turn into costly leaks inside the building. This case study shows how
AJS Environmental used a targeted brush coating system to seal and protect rooftop outlets on
a busy commercial site, preventing water ingress and extending the life of the roof.

Project Snapshot

Client: National-brand commercial property (rooftop plant area)
Location: South East UK
Service: Brush coating to seal drainage outlets on a flat roof
Key goals: Stop water tracking into the building, protect outlets, minimise disruption

The Problem: Failing Outlets on a Flat Roof

The client reported signs of damp and staining below a rooftop area that housed key building services.
Initial inspection showed that the drainage outlets were sound structurally, but the surrounding
surfaces and joints were weathered and starting to crack. If left untreated, water would continue to
track under the waterproofing layer and into the slab.

Because the area contained plant and access routes, the client needed a solution that was:
fast to install, highly durable and minimally disruptive to day-to-day operations.

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Engineer applying brush coating around a rooftop drainage outlet during preparation work — Brush coating work in progress on the rooftop drainage outlet.

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Our Solution: Targeted Rooftop Brush Coating

After completing a full visual assessment and confirming the outlets were suitable for refurbishment,
AJS Environmental recommended a specialist brush-applied coating system. This allowed us to
seal critical details around each outlet without the cost and disruption of full roof replacement.

Step-by-Step Approach

Preparation: Cleaned the affected areas, removed loose material and ensured the outlets were dry and sound.
Detailing: Focused on joint lines, cracks and vulnerable perimeters where water was most likely to track.
Brush Coating: Applied a high-performance coating by hand to achieve full coverage and penetration.
Build-Up: Applied additional coats as required to create a robust, flexible waterproof layer.
Final Checks: Inspected each outlet for continuity, adhesion and finish before sign-off.

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Careful brush application ensures full coverage around the outlet detail.

Inspection image showing the condition of the coated outlet on screen — Condition checked and recorded as part of our quality process.

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Quality Control and Inspection

Throughout the job, our engineers recorded the work and checked coverage around each outlet.
This ensured there were no pinholes, missed edges or weak points that could allow water back in.
Images and notes from the job were then supplied to the client as part of a simple
after-care report, giving them confidence that the risk areas had been treated properly.

Where requested, we can combine brush coating with CCTV drain surveys
and other diagnostic checks to give a complete picture of the drainage system’s condition.

Completed brush coating around a rooftop drainage outlet, fully sealed and protected — Completed brush coating: outlets fully sealed and protected against future leaks.

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The Results: Protected Outlets and Reduced Risk of Leaks

Once the coating had cured, the outlets were visibly transformed. The previously weathered
and cracked areas were now covered by a continuous, flexible barrier designed to withstand standing water,
thermal movement and day-to-day wear.

Water risk around the outlets was significantly reduced.
The client avoided the cost of major roof replacement works.
All works were completed with minimal disruption to the occupied building below.

Why Brush Coating Is a Smart Option for Flat Roof Drainage

Brush coating is an ideal refurbishment method where the structure is sound but joints,
upstands and outlet details are beginning to fail. It allows building owners to
extend the life of existing roofs and protect vulnerable areas without invasive construction.

Typical situations where brush coating is effective include:

Aging flat roofs around outlets, gullies and internal rainwater pipes.
Rooftop plant areas where access is restricted and downtime must be minimal.
Commercial properties experiencing intermittent leaks with no obvious single failure point.

Why Choose AJS Environmental for Brush Coating and Drainage Works?

AJS Environmental combines drainage expertise with safe access, confined space entry and specialist
coating skills. Whether we are cleaning, inspecting or protecting your drains and outlets,
the focus is always on safety, compliance and long-term value for the client.

What you can expect from us

Experienced engineers used to working on complex commercial sites.
Clear communication before, during and after the job.
Photographic evidence and reporting as standard.
Solutions tailored to your site, not one-size-fits-all fixes.

Need Brush Coating or Rooftop Drainage Support?

If you are dealing with leaks around outlets, damp patches below a flat roof or concerns about your rooftop
drainage, AJS Environmental can help. We work across Essex, London and the South East,
supporting commercial, industrial and public-sector clients.

Get in touch today to discuss your site and arrange a survey:

Rooftop Brush Coating Case Study: Sealing Flat Roof Drainage Outlets