How Do I Choose a Good Flat Roofing Contractor?

A flat roof is only as good as the person laying it. These are the questions, checks and red flags that separate a proper flat roofer from a risky one.

Start with what the roof actually needs

The best flat roofing contractor for you is the one who looks at the deck, the drainage and the edges before talking about materials. A good contractor will lift a corner, check for soft boards, look at where water sits after rain and ask how the roof is used. Someone who quotes a price over the phone without seeing any of that is guessing.

Flat roofs fail at the details far more often than in the middle of the membrane. Upstands against walls, outlets, trims and the junction with any window or door sill are where water gets in. When you speak to contractors, notice who asks about those details and who only talks about square metres.

They should offer more than one system

EPDM rubber, GRP fibreglass and torch-on felt each suit different roofs. Rubber copes well with movement and is quick to lay in one sheet on simple shapes. Fibreglass gives a hard, walkable finish that suits balconies and roofs with lots of detailing. Modern felt systems are well proven on garages and extensions. A contractor who only ever fits one of them will recommend that one every time.

We fit all three, which is why our advice starts from the roof rather than the product. If you want the detail, our EPDM, felt and GRP comparison sets out the trade-offs side by side.

Questions worth asking every contractor

Ask whether the existing covering is being stripped or overlaid, and why. Overlaying can be fine on a sound deck, but it hides problems if the boards underneath are wet. Ask what happens if rotten decking is found once the old roof is off, and how that will be priced before it is done.

Ask how the edges and upstands will be finished, whether the fall will be improved if water currently ponds, and whether insulation will be added. Building regulations can apply when a large proportion of a roof is renewed, so ask who is responsible for that. Finally, ask what the guarantee covers and who stands behind it.

What a proper quote looks like

A written quote should name the system and the manufacturer, say whether the job is a strip or an overlay, list the deck, insulation and trims, and explain how any extra work will be handled. It should say who removes the waste and what access is needed. Vague one-line quotes make it impossible to compare contractors fairly.

Every quote we give is written and free, and it sets out exactly what we plan to do so you can hold it up against anyone else's.

Red flags to walk away from

Pressure to sign on the day, a large cash deposit before any materials are ordered, a price that drops sharply the moment you hesitate, or a contractor who cannot tell you which membrane they will use. Door knockers who have noticed a problem with your roof from the street deserve extra caution.

Be wary too of anyone who suggests a quick coat of paint-on sealant over a failing flat roof as a long-term fix. Coatings have a place as a short-term measure, but they will not cure a wet deck or poor drainage.

Local knowledge still matters

A contractor based nearby can come back quickly if something needs attention and will know the property types in the area, from stone cottages with lean-to extensions to post-war homes with flat roofed garages. We are based in Witney and work across Oxford and Oxfordshire, so aftercare is never a long drive away.

Should a flat roofing contractor visit before quoting?

Yes. The condition of the deck, the falls and the edge details all change the job, and none of them can be judged properly from a photo or a phone call.

Is overlaying an old flat roof ever acceptable?

Sometimes, when the deck is dry and sound. If the boards are soft or wet, overlaying traps the problem, so the old covering should come off.

Why do different contractors recommend different materials?

Often because each one only fits a single system. A contractor who fits rubber, fibreglass and felt can recommend whichever suits your roof best.

What should a flat roof quote include?

The named system, strip or overlay, deck and insulation work, edge trims, waste removal and how any hidden problems will be priced.

Do you give free written quotes for flat roofs?

Yes. We look at the roof, explain the options and put a written quote in your hands at no cost.

Ask us the same questions you ask everyone else. We will look at the roof, answer them straight and leave you with a written quote.

Arrange a Flat Roof Visit

Evans Roofing & Maintenance Ltd, Witney, Oxfordshire. Call 07960 482233 for a free written quote.