The Only Flat Roofing Warranty Backed by the Manufacturer
When it comes to flat roofing in Birmingham, there’s one thing most roofers can’t offer you: a warranty backed by the manufacturer rather than just their own word. SB Margan Roofing are certified Hambleside Danelaw Dryseal Approved Installers — which means every Dryseal GRP flat roof we install comes with a 20-year manufacturing warranty, registered in the manufacturer’s name, independently of us.
That matters because a contractor’s guarantee is only as good as the contractor. If a company closes, moves, or simply stops answering calls, your guarantee disappears with it. A Hambleside Danelaw manufacturer warranty is tied to the product and the property — not to us.
Every Dryseal GRP flat roof installed by SB Margan Roofing carries a 20-year manufacturing warranty from Hambleside Danelaw Building Products. This is not a contractor guarantee. It is a manufacturer warranty, registered independently to the property.
What is Dryseal?
Dryseal is a premium GRP (Glass Reinforced Polymer) flat roofing system manufactured in the UK by Hambleside Danelaw Building Products. Unlike traditional wet lay-up GRP systems — where liquid resin and fibreglass matting are applied on site — Dryseal uses pre-cured factory-manufactured GRP components that are dry-fixed to the roof deck. The only liquid used on site is a cold-applied resin that seals the joints between components.
This is a fundamental difference from other GRP systems. Because the panels are made in a controlled factory environment rather than hand-laid on a roof in variable weather, the quality and consistency is higher. And because the system is cold-applied with no heat guns or naked flames, it is significantly safer during installation.
No Naked Flames
Cold-applied resin only. No heat guns, no torches — a major safety advantage over torch-on or hot-applied systems, especially near timber structures.
Pre-Cured GRP Panels
Panels are factory-manufactured under controlled conditions, not hand-laid on site in variable weather. Consistent quality every time.
Fully Monolithic Surface
Joints between panels are cold-resin-sealed to create a single seamless waterproof barrier. No laps, no overlapping seams to split or lift.
Walk-On & Traffic-Ready
The cured GRP surface is hard, rigid and capable of handling regular foot traffic without damage or marking.
Fully Weatherproof Same Day
A Dryseal installation is fully weatherproof on the day of installation. Most standard extension roofs are completed in a single working day.
Low Maintenance
Once cured, Dryseal GRP requires virtually no maintenance over its lifetime. It won’t blister, peel, crack at the edges or lift like older felt systems.
What Does “Approved Installer” Mean?
Hambleside Danelaw only issue their 20-year manufacturer warranty when their Dryseal system is installed by a trained and approved contractor. They test and certify installers to ensure the product is installed exactly to their specification — including correct deck preparation, priming, panel fixing, joint sealing and trim detailing. Without this certification, the warranty is not available.
SB Margan Roofing passed the Hambleside Danelaw training and certification programme and are listed as an approved installer on their website. You can verify our listing directly on the Hambleside Danelaw website ↗
How a Dryseal Installation Works
See the three stages of a Dryseal installation carried out by Sergiu on a Birmingham rear extension. The whole job was completed in one day.
Deck Prep & Panel Installation
The existing covering is stripped back to the deck. Any damaged or soft sections of OSB or plywood are replaced. Pre-cured GRP panels are then dry-fixed to the deck with screws at set centres.
Resin & Reinforced Fibre Matting — Ready for Topcoat
Cold-applied Dryseal resin is worked into the joints between panels together with reinforced fibre matting, bonding everything into a single seamless waterproof layer. Once cured, the surface is primed and ready for the topcoat.
Topcoat Applied — Roof Complete
The Dryseal topcoat is applied across the entire surface, providing UV protection, the finished colour, and the final hard-wearing layer. Fully weatherproof the same day — cures completely overnight.
Watch the Dryseal Installation Process
This video by Skillbuilders shows the Dryseal system being installed step by step — exactly the process we follow on every job.
Flat Roof Repairs — All Systems Covered
For new installations we only use Dryseal — because it’s the best system on the market and the only one that comes with a manufacturer warranty. But when it comes to repairs, we work on all flat roof types, regardless of what system is already in place:
- Dryseal GRP repairs — panel replacements, joint resealing, trim repairs
- Traditional wet-lay GRP repairs — cracked or delaminated sections, edge repairs
- EPDM rubber membrane repairs — splits, punctures, joint failures, edge lifting
- Torch-on felt and bitumen repairs — blistering, cracking, edge failures, ponding issues
- Lead flat roof repairs — splits, nail sickness, joint failures
We’ll always give you an honest assessment — repair where it’s the right call, replacement when the covering has genuinely run its course. We won’t push a full re-roof if a targeted repair is all that’s needed.
Applications
Dryseal GRP is suitable for any flat or low-pitched roof up to 70°. We install it on:
- Single and double-storey rear and side extensions
- Side return extensions and infill roofs
- Garage roofs (single and double)
- Outbuildings, sheds and bike stores
- Bay window tops and porch roofs
- Dormer cheeks, tops and flat sections
- Flat sections within pitched roofs (valleys, abutments)
Signs Your Flat Roof Needs Attention
- Blistering or bubbling of the roof surface
- Visible cracking, splitting or crazing
- Ponding water that doesn’t drain within 48 hours
- Damp patches on the ceiling beneath the flat roof
- Moss or weed growth through the covering
- Felt edges lifting away from the fascia or upstand
Frequently Asked Questions
What warranty do I get on a Dryseal flat roof?
Every Dryseal GRP flat roof installed by SB Margan Roofing comes with a 20-year manufacturer warranty from Hambleside Danelaw Building Products. This is registered to the property and issued in the manufacturer’s name — independent of the installer. It is separate from and in addition to our own workmanship guarantee.
What’s different about Dryseal compared to standard GRP?
Standard GRP uses liquid resin and fibreglass matting applied wet on site. Dryseal uses pre-cured factory-manufactured panels fixed dry to the deck, with only a cold-applied resin sealing the joints. This means no naked flames, no heat guns, higher consistent quality, and a manufacturer warranty that no standard GRP system can match.
How long does a Dryseal installation take?
Most standard extension flat roofs are completed in a single working day. We prep the deck, fix the panels, seal the joints with cold resin, and the roof is fully weatherproof the same day. The resin cures fully overnight.
Can you repair my existing flat roof even if it’s not Dryseal?
Yes. For new installations we only use Dryseal, but we carry out repairs to all flat roof types — felt, EPDM rubber, standard GRP and lead. We’ll assess what you have and give you an honest view on whether repair or replacement makes more sense.
Do I need planning permission for a flat roof?
Re-roofing or replacing an existing flat roof generally falls under permitted development and doesn’t require planning permission, as long as you’re using similar or better materials. We can advise on this when we visit for a survey.
