Choose a complete system for the space below
The best flat roofing option for an extension or garage depends on how the space is used, the deck condition, the roof shape and the details around its edges. A heated kitchen extension needs a different thermal design from an unheated garage used for storing tools. Start with that distinction before comparing surface materials.
If a garage may later become a home office or living space, discuss that possibility early. A cheaper covering installed now can leave awkward insulation work later. Homeowners in Blackpool should ask for a specification covering the deck, moisture control, insulation, waterproofing and drainage together, so the quotation describes a finished roof rather than a roll of material.
GRP fibreglass for a carefully prepared deck
GRP forms a resin-and-glass laminate with shaped edge trims. It can suit straightforward domestic roof shapes, with the deck and movement details designed for the system. The quality of the substrate, weather conditions during installation and correct application are important to the result.
As a current product example, the Cure It ONE installation manual states a 20-year manufacturer materials guarantee. This applies to its specified system and conditions, not every fibreglass roof. Ask separately about workmanship cover. Paul Jones Roofing Contractor lists fibreglass roofing among its services, so it is a relevant option to discuss where the roof construction suits it.
EPDM rubber for flexible waterproofing
EPDM is a rubber membrane that can cover a simple roof with relatively few seams, depending on the dimensions and system. Its flexibility can be useful, but the perimeter, bonding and details around pipes or rooflights still need careful workmanship. A large uninterrupted sheet does not make those junctions unimportant.
The installer should explain how the membrane meets walls and gutters and how future maintenance access will be protected. Ask whether the exact proposed system is suitable for the substrate and the building’s exposure. EPDM is one of the systems named on the business’s commercial roofing page; suitability for your extension or garage should be confirmed through the survey.
Reinforced bitumen and other alternatives
Modern reinforced bitumen roofing normally uses a specified multi-layer system. It differs substantially from basic shed felt. It can be a practical refurbishment choice where the existing build-up and detailing suit it, although any use of heat needs a properly planned safe installation method.
Single-ply membranes and liquid-applied waterproofing provide other possibilities for particular shapes and substrates. Liquid systems can be useful around complicated details, but application thickness, reinforcement and preparation are system-specific. These are comparisons to discuss, not a claim that every contractor supplies every product. Ask which alternatives are available for your roof and why one has been recommended.
Get insulation and condensation control right
A warm-roof arrangement places insulation above the structural deck, while other arrangements need their own moisture and ventilation design. Putting insulation wherever it seems to fit can create cold surfaces or trapped moisture. Do not ask a contractor to copy another property’s build-up without considering your building.
For a heated extension, establish how the roof connects thermally to the walls and how the internal air and vapour-control layer is made continuous. An unheated garage has different requirements, but intended future use still matters. If replacing an existing covering, discuss the applicable building regulations and whether insulation improvements are required as part of the project.
Drainage details can decide between otherwise suitable options
A “flat” roof usually still needs a slope towards drainage. Bauder’s May 2026 commentary on BS 6229:2025 explains the minimum completed fall of 1:80 for most roofs, with design determined by the structure and survey. That equals 12.5 mm fall per metre; it is not an instruction to ignore construction tolerances.
Position rooflights and outlets together, rather than adding the opening after the drainage plan is fixed. Check available height at doors, wall flashings and adjoining windows before adding insulation. A material choice that fits the budget may still be unsuitable if it leaves too little room for robust junctions. These constraints should be resolved on paper before the old covering is removed.
Compare quotations by scope, not just headline price
Set out whether quotes include stripping, disposal, deck replacement, insulation, trims, outlets and internal making good. Ask which items are provisional because they depend on opening the roof. A quotation to replace only the covering is not directly comparable with one that rebuilds the assembly underneath.
Also specify how the roof will be used. A roof intended for maintenance access is different from a terrace carrying furniture and regular foot traffic; waterproofing alone does not make a roof suitable for that use. For an extension or garage in Blackpool, Paul Jones Roofing Contractor can discuss flat roof installation and the practical requirements of the building, helping you compare appropriate options.
Summary
Select an extension or garage roof by considering insulation, drainage, access and substrate alongside the covering. GRP, EPDM and reinforced systems each have situations where they make sense. Follow the service link to discuss an appropriate flat roofing specification with Paul Jones Roofing Contractor.
