Description
Not every fire-rated roof is a warehouse. Porches, bay window roofs, dormer cheeks and garden buildings often sit just as close to a boundary as a commercial unit does, and they don't need — or want to pay for — the heavier 450g or 600g systems built for larger jobs. This is the lighter 300g version of our fire-rated GRP kit: the same BROOF(t4)-rated resin and topcoat, a lighter chopped-strand matting sized to smaller structures, and every tool needed included.
It cures to the same seamless, jointless, UV-stable surface as our other GRP systems, just calibrated — matting weight and kit sizing both — for roofs where a heavier-duty system would be overkill. Sizes run from a 12m² porch or bay window roof right up to a 66m² garage or garden room roof.
Key benefits
- Fire-rated to BROOF(t4) — resin and topcoat carry the classification
- 300g chopped strand matting — right-sized for smaller domestic structures
- Full tool kit included — nothing extra to buy to get started
- One seamless, jointless membrane, UV-stable, summer and winter installation
- 5 sizes from 12m² to 66m², matched to smaller roofs and outbuildings
Where it's used
Porches, bay window roofs, dormer cheeks, sheds and smaller garden buildings sitting close to a boundary or otherwise requiring a fire-rated covering under Building Regulations. For larger or heavier-traffic jobs, our 450g Fire-Rated GRP Kit (5–30m², with tools) and 600g Fire-Rated GRP Kit (10–100m², materials only) cover heavier-duty and commercial-scale roofs.
Specification
| Size | Coverage | Matting Weight | Fire Rating | Tools Included |
|---|---|---|---|---|
| 12m² | Up to 12m² | 300g CSM | BROOF(t4) | Yes |
| 26m² | Up to 26m² | 300g CSM | BROOF(t4) | Yes |
| 40m² | Up to 40m² | 300g CSM | BROOF(t4) | Yes |
| 53m² | Up to 53m² | 300g CSM | BROOF(t4) | Yes |
| 66m² | Up to 66m² | 300g CSM | BROOF(t4) | Yes |
Ordering & installation guidance
Measure your roof deck area and order the size at or above it — GRP is laid as one continuous laminate, so size up rather than down if you're between two sizes. Deck should be sound, dry timber, OSB3 or plywood, minimum 18mm. Finish the perimeter with our GRP roof edge trim packs or GRP simulated lead flashing trim, and protect any high-traffic areas with our EPDM walkway pads.
FAQ
How is this different from your 450g fire-rated kit?
Both are fire-rated to BROOF(t4) and install the same way. This 300g kit uses a lighter matting sized for smaller structures (12–66m²), while the 450g kit is a heavier-duty laminate sized 5–30m² — pick whichever size range matches your roof.
Do I need the fire-rated version?
Check with your building control surveyor or Approved Document B if your roof is close to a boundary or falls under a fire-performance requirement — it's a site-specific need, not a universal one.
What's included in the kit?
Fire-rated resin and topcoat for your chosen area, 300g chopped strand matting cut to size, and a full set of application tools.
Can I lay this over an existing felt or asphalt roof?
No — GRP needs a sound timber, OSB3 or plywood deck. Strip back an existing felt or asphalt covering to a suitable board first.
How is it delivered?
Dispatched from UK stock — check the product page at checkout for the current delivery estimate to your postcode.
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