Flat Roofing North London – EPDM, GRP & Felt Specialists | MJM Roofing


Serving North London — Islington · Camden · Highgate · Hampstead · BarnetCall us: +44 7728 290555 · Open 7 days for emergencies

Expert Flat Roofing for North London Properties

EPDM rubber, GRP fibreglass and high-performance felt systems for extensions, garages, dormers and commercial properties. Long-life installations with manufacturer-backed guarantees.

Up to 25-Year Guarantees
Certified Installers
Fully Insured

Why Your Flat Roof Matters

Flat roofs are everywhere in North London — on rear extensions, garage roofs, dormers, bay window overhangs and balconies. They’re also one of the most common sources of leaks and water damage when they fail.

The old-style felt flat roofs that were fitted to thousands of London properties in the 1970s, ’80s and ’90s have a limited lifespan. Many are now cracking, blistering and letting water in. If your flat roof is more than 15 years old, it’s likely approaching the end of its life.

Modern flat roofing systems — EPDM rubber and GRP fibreglass — are a completely different proposition. They’re seamless, UV-resistant, and designed to last 25 years or more with virtually zero maintenance. We install both systems and will recommend the best option for your specific situation.

Our Flat Roofing Promise

  • Manufacturer-backed guarantees. We’re certified installers, which means your new flat roof comes with a guarantee backed by the material manufacturer — not just us.
  • Proper preparation. A flat roof is only as good as the deck beneath it. We check and replace any rotten decking boards, ensure correct falls for drainage, and add insulation where needed.
  • Seamless finish. Both EPDM and GRP systems create a single, seamless waterproof membrane with no joints to fail — unlike traditional felt which relies on overlapping seams.
  • Clean, quick installation. Most domestic flat roofs are completed in 1-2 days with minimal disruption.

Which System Is Right for You?

We install all three main flat roofing systems. Here’s how they compare.

GRP Fibreglass

Our Most Popular System

A hard-wearing, seamless fibreglass system that’s applied as a liquid and cures to form a single, watertight shell. Ideal for extensions and areas that may need to be walked on.

25+ year lifespan
Completely seamless
Can be walked on
Choice of finish colours

EPDM Rubber

Maximum Flexibility

A single-piece rubber membrane bonded to the roof deck. Extremely durable and flexible — it moves with the building without cracking. Perfect for garages and outbuildings.

20-25 year lifespan
Single-piece membrane
UV & weather resistant
Low maintenance

High-Performance Felt

Budget-Friendly Option

Modern torch-on felt systems are a significant upgrade over old-style poured felt. A cost-effective choice for smaller areas where budget is a primary consideration.

10-15 year lifespan
Most affordable option
Quick installation
Good for sheds & small areas

Our Flat Roofing Process

From first call to finished roof — here’s what to expect.

Survey & Quote

We inspect your existing flat roof, check the timber deck and drainage, and provide a clear, itemised written quote with our recommendation.

Preparation

We strip the old covering, check and replace any damaged decking boards, and ensure proper falls for drainage. We add insulation where required by Building Regulations.

Installation

Your new flat roof system is installed by our trained, certified team. GRP and EPDM systems are applied as seamless membranes — no joints to fail.

Guarantee

We walk you through the completed work, clean up completely and provide your manufacturer-backed guarantee alongside our own workmanship warranty.

Flat Roofing FAQs

Quick answers to the questions we hear most often.

How long does a new flat roof take to install?
Most domestic flat roofs — extensions, garages, dormers — are completed in 1-2 days. Larger or more complex projects may take a little longer, but we’ll give you a clear timeline upfront.
Should I choose GRP or EPDM?
Both are excellent systems. GRP is slightly more durable underfoot and offers a wider choice of finish colours — ideal for balconies and areas you’ll walk on. EPDM is extremely flexible and handles building movement well — making it great for garages and outbuildings. We’ll recommend the best option when we survey your roof.
Can you overlay my existing flat roof?
In some cases, yes — EPDM can sometimes be laid over an existing surface if the deck beneath is sound. However, we generally recommend stripping back to the deck so we can inspect the timbers and ensure proper drainage falls. It’s the only way to guarantee a lasting result.
Do I need Building Regulations approval for a new flat roof?
If more than 25% of the roof area is being replaced, Building Regulations require that insulation is upgraded to current standards (Part L). We handle this as standard and ensure your new roof is fully compliant.

Ready for a New Flat Roof?

Get a free, no-obligation quote for your flat roof replacement or repair. We’ll recommend the best system for your property and budget.