The key point
Choose a specified roof system, not just a material name. Compare the supporting deck, insulation and moisture-control design, drainage, junction details, intended use and written guarantee conditions. A premium covering cannot compensate for an unsuitable underlying specification.
What the three names describe
EPDM is a synthetic-rubber membrane. Supplier PermaRoof describes both conventional and fleece-backed products; the accessories and installation requirements depend on the selected system. [1]
GRP is glass-reinforced plastic, commonly called fibreglass roofing. Roofing resin is part of a system rather than a stand-alone paint: Cromar's technical information directs installers to its complete application guidance. [2]
Reinforced felt refers to bituminous membrane roofing, not simply basic shed felt. IKO's published example includes different system components and specified application options. [3]
Compare what matters on your roof
| System | What to ask about | Avoid assuming |
|---|---|---|
| EPDM rubber | Membrane grade, layout, junctions, adhesive compatibility and edge details. | That a large sheet removes the need to detail outlets, corners or penetrations. |
| GRP fibreglass | Deck specification, reinforcement, trims, movement details and curing conditions. | That the same specification suits every roof size, shape or use. |
| Reinforced felt | Full layer build-up, application method and treatment of sensitive details. | That all products sold as felt have identical performance or terms. |
Ask each contractor to name the proposed system and set out the components. Without that, apparently competing quotations may describe different roofs.
The waterproof layer is only part of the roof
For a replacement, establish whether the existing deck will be inspected, retained or replaced. Ask how concealed damage would be recorded and priced. An offer to cover over an existing roof should explain why the existing construction is suitable, not merely say that an overlay is cheaper.
Where the roof is over heated accommodation, discuss insulation and moisture-control design as part of the proposal. Ask who will establish the building-regulations requirements. Do not assume the existing build-up can remain unchanged because the new surface looks similar. [4]
Discuss drainage and every junction
List the features the quotation needs to cover: wall abutments, rooflights, outlets, edges and any pipes or other penetrations. Ask how rainwater is intended to leave the roof and what is being done about any existing drainage problem.
A photograph of a neat finished surface is not a full specification. An honest comparison gives attention to the parts that are less visible as well as the main field of the roof. Ask what the contractor will inspect on completion and what records you will receive.
A roof is not automatically a terrace
Explain how the roof will be used. Occasional maintenance access, regular foot traffic, planters and a usable terrace are different requirements. Do not assume a new waterproof finish makes an existing roof suitable for people, furniture or extra loads.
The proposal should identify permitted use and any protective finish required. Where structural or design advice is necessary, that needs to be established before choosing the covering or ordering work.
Read guarantee conditions rather than headline years
A product's expected service life, a manufacturer's guarantee and an installer's workmanship guarantee are not interchangeable. The IKO system example, for instance, attaches conditions to its guarantee, including specification and contractor requirements. That is not a guarantee offered by Roofcare London. [3]
Request the actual terms applicable to your quotation: provider, scope, exclusions, registration, maintenance and transfer arrangements. Do not apply a claim about one brand to every roof made from the same broad material.
Get a flat-roof quotation you can compare
Tell Roofcare London where the roof is, what lies below it and why you want work carried out. We provide flat-roof services alongside roof repairs and installations. The flat roofing service page explains the work we cover; the form below lets you describe your property.
For budgeting, compare written system specifications rather than an isolated price per square metre. Access, preparation and details need to be understood before a figure becomes meaningful.
Sources & further reading
Guidance links supplied with the articles; important rules should be reconfirmed for your property. These sources support the linked factual points; they do not endorse Roofcare London or replace an assessment of your property.
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