300g Kit With Tools Porch, Bay, Roofs
Used for this product group. View the category to choose the right products and compatible options.
Lightweight GRP Kits for Small Roofs
300g GRP Roofing Kits for Small Flat Roofs
Shop lightweight 300g GRP roofing kits for sheds, porches, bay windows, dormers and smaller domestic flat roofs. A practical fibreglass roof system for lighter-use projects where a full heavy-duty laminate is not required.
Small roof — right kit
300g suits sheds, porches, bay windows and dormers. For garages and extensions, step up to the 450g kit.
Showing all 6 resultsSorted by price: low to high
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Sale!
2.5–6.6m² 300g GRP Flat Roof Kit – Bay Windows, Porches & Sheds Tools Included
Original price was: £139.99.£133.33Current price is: £133.33. ex VAT£159.99 inc VAT£20.20 / m²Add to cart -
Sale!
10–14m² 300g GRP Flat Roof Kit – Small Sheds, Porches & Flat Roofs Tools Included
Original price was: £180.83.£172.49Current price is: £172.49. ex VAT£206.99 inc VAT£12.32 / m²Add to cart -
Sale!
15–22m² 300g GRP Flat Roof Kit – Garden Rooms, Sheds & Small RoofsTools Included
Original price was: £292.49.£278.33Current price is: £278.33. ex VAT£333.99 inc VAT£12.65 / m²Add to cart -
Sale!
22–30m² 300g GRP Flat Roof Kit – Garages, Workshops & Domestic Roofs Tools Included
Original price was: £328.33.£312.49Current price is: £312.49. ex VAT£374.99 inc VAT£10.42 / m²Add to cart -
Sale!
30–37m² 300g GRP Flat Roof Kit – Larger Garages & Lightweight Roofs Tools Included
Original price was: £384.99.£365.83Current price is: £365.83. ex VAT£438.99 inc VAT£9.89 / m²Add to cart -
Sale!
37–44m² 300g GRP Flat Roof Kit – Large Lightweight Domestic Roof Kit Tools Included
Original price was: £435.83.£414.16Current price is: £414.16. ex VAT£496.99 inc VAT£9.41 / m²Add to cart
Quick category guideQuick guide to 300g GRP Roofing Kits for Small Roofs
This category is for installing a 300g light-duty GRP fibreglass roof over a suitable OSB3 or timber deck. Use it to check the product type, surface compatibility, preparation work and related CRS options before ordering.
Choosing guide
Need help choosing?
Use these quick checks to make sure this category suits the job before ordering.
What is this category for?
Choose 300g GRP Roofing Kits for Small Roofs for installing a 300g light-duty GRP fibreglass roof over a suitable OSB3 or timber deck.
Good choice when
- Use this category for installing a 300g light-duty GRP fibreglass roof over a suitable OSB3 or timber deck.
- Use it when the surface is new OSB3 or suitable timber roof deck.
- Use it when the measurements, preparation work and related accessories have been checked.
Not the right choice if
- Do not use this category when the existing roof only needs a quick repair, coating or overlay rather than a new GRP system.
- Do not use it when the roof is unsafe or unsuitable without preparation.
- Do not use it as a shortcut if another CRS system is a better fit.
Next step
Choose the kit weight, check the roof size, then add the correct trims and tools before ordering.
Also useful for
- 300g GRP Roofing Kits for Small Roofs
- GRP fibreglass roofing - 300g light-duty
- New flat roof
- GRP roofing kit
- fibreglass roof kit
- flat roof kit
- OSB3 roof deck
Related pages
300gMat weight
20+yrsLifespan
4.6★1,300+ reviews
UKStock
Small roof — right kit
300g suits sheds, porches, bay windows and dormers. For garages and extensions, step up to the 450g kit.
When Should I Use A 300g GRP Roofing Kit?
300g GRP roofing kits are designed for smaller domestic flat roofs and lighter-use projects. They are best suited to sheds, porches, bay windows, small dormers and outbuildings where the roof is not expected to take heavy foot traffic.
Best For Small Roofs
Ideal for sheds, porches, bay windows, small dormers and lighter domestic flat roofs.
Need Standard Strength?
For garages, extensions and most domestic flat roofs, move up to a 450g GRP roofing kit.
Need Heavy Duty?
For larger roofs, stronger laminates or more demanding use, consider a 600g GRP roofing kit.
Unsure On Size?
Use the CRS Roof Mate calculator to estimate kit size and materials before ordering.
Why CRS
300g laminate — lighter weight for lighter-use domestic roofs
Best for sheds, porches, bay windows and dormers
Includes resin, 300g chopped strand mat, catalyst and topcoat
Do not use on garages or extensions — upgrade to 450g for those
Optional tool packs available alongside the kit
T&G OSB3 deck and Prymax primer required before laminating
Not right if
Existing roof needing repair or overlay — not a new deck
Rotten or structurally failed deck — replace deck first
What is a 300g GRP roofing kit best for?
300g GRP roofing kits are best for sheds, porches, bay windows, small dormers and lighter domestic flat roofs.
Can I use a 300g GRP kit on a garage roof?
For most garage roofs, a 450g GRP roofing kit is usually the better standard domestic option. 300g is better suited to smaller and lighter-use roofs.
What does a 300g GRP kit include?
Most 300g kits include roofing resin, 300g fibreglass matting, catalyst and topcoat. Some options may also include tools.
Do I need trims with a 300g GRP roof kit?
Most GRP roofs require trims around the roof edges and details. The trims needed depend on the roof shape and edge design.
Is 300g GRP suitable for heavy foot traffic?
No. For heavier-duty use, larger roofs or walkways, a 600g GRP roofing kit is normally more suitable.
300g GRP Roofing Kits For Small Flat Roof Projects
300g GRP roofing kits are lighter fibreglass roofing kits designed for smaller domestic flat roof projects. They are commonly used on sheds, porches, bay windows, small dormers and outbuildings where a simple waterproof GRP system is required.
Each kit is built around the core GRP roof materials: resin, fibreglass matting, catalyst and topcoat. Depending on the roof detail, trims and tools may also be required to complete the installation.
300g vs 450g GRP Roofing Kits
Choose 300g for smaller, lighter-use roofs. For garages, extensions, garden rooms and most standard domestic flat roofs, 450g is usually the better choice because it creates a stronger laminate for everyday domestic use.