As the UK enjoys its warmer summer months, many homeowners take advantage of the dry weather to tackle roofing jobs. One of the most popular choices for a durable, long-lasting roof is fibreglass. In this post, we explore everything DIYers need to know about fibreglass roofing in summer, including curing advice, safety tips, and why GRP roofing is ideal for warm-weather projects.
Why Choose Fibreglass Roofing in Summer?
Summer is arguably the best time of year to install fibreglass roofing in the UK. Warmer temperatures and longer daylight hours create optimal conditions for fibreglass resin to cure, making it easier for DIYers to achieve a professional-quality finish.
Fibreglass (or GRP – Glass Reinforced Plastic) roofing is a tough, seamless, and low-maintenance option ideal for flat roofs, garages, extensions, and garden buildings. When installed correctly, a GRP roof can last over 25 years with minimal upkeep — making it a favourite for both tradespeople and DIY homeowners.
Safety First: Roofing in the Summer Heat
Before diving into the technical side of fibreglass roofing in summer, it’s vital to highlight some key safety considerations:
Hydration: Always stay hydrated. Working on a roof in the sun can quickly lead to dehydration and heat exhaustion.
Protective Clothing: Wear lightweight, breathable clothing along with essential PPE — gloves, safety goggles, and non-slip footwear are musts.
Sun Protection: Apply high-SPF sunscreen regularly and wear a hat to protect yourself from UV rays.
Timing: Try to start early in the morning or later in the afternoon when the sun isn’t at its peak.
Safe Ladder Use: Ensure ladders are secure and stable. Avoid working alone and keep a mobile phone to hand in case of emergency.
Best Practices for GRP Fibreglass Roofing in Summer
If you’re planning a fibreglass roofing project in summer, timing and technique are everything. Here are the essential steps and tips to follow for a smooth installation:
1. Prepare the Decking Properly
Start with clean, dry OSB3 boards. Make sure they’re securely fixed with no movement. The decking must be completely dry to ensure good adhesion with the fibreglass laminate.
2. Choose the Right Resin for the Temperature
Temperature affects how quickly your resin will cure. For fibreglass roofing in summer:
Use summer-grade catalyst if available. It has a slightly slower curing time to compensate for higher ambient temperatures.
Avoid mixing large batches, as the heat can accelerate the curing process too quickly, especially under direct sunlight.
Keep resin and catalyst in the shade until use to avoid premature curing.
3. Apply in Cooler Parts of the Day
Midday sun can cause resin to “flash off” — curing too quickly and leaving a brittle, poor-quality finish. Aim to apply resin either early in the morning or late afternoon when the roof surface is cooler.
4. Monitor Cure Times Carefully
In warmer temperatures, resin and topcoat will cure much faster. Check the manufacturer’s guidelines, but typically:
In 20–25°C temperatures, resin can begin curing in 10–20 minutes.
Work in small sections to ensure full saturation of the fibreglass mat before curing starts.
Do not walk on the laminate until it has fully cured — this can take 2–4 hours depending on the temperature and air flow.
5. Don’t Forget the Topcoat
Once your fibreglass mat has cured, apply the topcoat to seal and weatherproof the roof. Again, watch for high temperatures. A topcoat applied too thickly or in direct sun may blister or become patchy.
Use a UV-resistant topcoat for added protection, particularly if your roof is in constant sun exposure.
Troubleshooting Common Summer Fibreglass Roofing Issues
Resin too hot? Move materials into shade and reduce catalyst ratio within the recommended range.
Curing too fast? Work in smaller batches and avoid black or heat-absorbing containers that warm the resin.
Surface sticky or undercured? Check mix ratios — high heat can sometimes cause uneven curing if not mixed thoroughly.
Why DIYers Trust Roofing Kits Direct
At Roofing Kits Direct, we provide high-quality fibreglass roofing kits that are ideal for summer installations. All our kits come with clear instructions, professional-grade resins, and reliable delivery so you can tackle your DIY project with confidence.
Whether you’re refurbishing a garage roof or installing a new flat roof on a garden room, our GRP roofing kits are designed to give you everything you need for a successful summer installation.
Final Thoughts: Fibreglass Roofing in Summer Done Right
DIY fibreglass roofing in summer is a rewarding project — but only if you prepare properly. By choosing the right time of day, using summer-grade materials, and following safe working practices, you can achieve a smooth, long-lasting fibreglass finish that withstands the elements for years to come.
Remember: when it comes to fibreglass roofing in summer, timing and technique are key. For all your GRP roofing needs, visit www.roofingkitsdirect.co.uk and explore our full range of ready-to-use roofing kits.