Flat Roof Replacement Costs in Eastbourne
Eastbourne's coastal climate makes flat roof specification more important than in most UK locations. Salt-air UV degradation, thermal cycling in the sea air, and the risk of salt saturation in membrane seams all shorten the life of undersupplied flat roof systems significantly. We install GRP fibreglass and EPDM rubber only — felt is not a specification we offer on any Eastbourne property.
GRP Flat Roof Costs by Size
| Application | Size | GRP Cost (2025) |
|---|---|---|
| Garage or single outbuilding | 15–25m² | £1,500–£2,500 |
| Single-storey extension | 20–40m² | £2,500–£5,000 |
| Large extension or combined area | 40–60m² | £4,500–£7,000 |
| Large flat roof | 60–80m² | £6,500–£9,000 |
| Bay window flat roof | 3–8m² | £600–£1,200 |
| Porch flat roof | 4–10m² | £700–£1,400 |
What Is Included in Our Eastbourne Flat Roof Price
All GRP flat roof quotes include: condition survey and deck assessment; removal of existing felt or membrane; deck inspection and any soft board replacement; GRP laminate application — minimum 600g chopped strand mat; topcoat to colour and specification; trim and edge detail to all perimeters; drainage fall confirmation; site clean; and the manufacturer's 25-year product guarantee plus our 10-year workmanship guarantee.
Deck Condition and Cost Implications
The single biggest variable in flat roof replacement cost is deck condition. If the existing timber deck is soft, wet or rotted — which is common on Eastbourne properties where felt has been leaking for years before the homeowner notices — the deck boards need replacing before GRP can be applied. Deck replacement typically adds £300–£800 depending on area. We assess deck condition at survey stage and include any required deck work in the itemised quote.
GRP vs EPDM — Which Is Right for Your Property?
GRP is our standard specification for most Eastbourne flat roofs. It is rigid, walkable, and seamless up to the panel joins — which are GRP-laminated, not just taped. EPDM rubber is a single-piece membrane suitable for very large areas (80m²+) where the number of GRP panel joins would become a maintenance consideration, or for complex shapes. Both carry equivalent guarantees and both outperform felt significantly in coastal conditions. We advise on the right system at survey stage.
Free flat roof survey — Eastbourne and East Sussex
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