If you’re facing a lead roof replacement on a garage, extension or outbuilding, you already know it’s not going to be cheap. Lead has been the traditional choice for decades, but these days the combination of material costs, specialist labour and the constant risk of theft makes a lot of people stop and look for a better option. Fibreglass roofing (GRP) has become a genuinely trusted alternative for exactly this situation. It’s lighter, more practical, and when you use the right trims it can deliver a very convincing traditional appearance without the downsides. Why lead roof replacements feel so expensive and risky right now Lead work still looks great when it’s done properly, but there are some real pressures: Cost - Material prices move around and you usually need experienced lead workers, which pushes the total bill up quickly. Theft risk - Lead has scrap value, so accessible roofs remain a target. While numbers have improved in some areas thanks to better security, it’s still a legitimate worry for many homeowners and small builders. Historic England has published useful guidance on the issue and replacement options. Weight and movement - Lead is heavy and it expands and contracts with our temperature swings. Over time that can lead to cracking or leaks, especially on older structures. Maintenance - It needs occasional checking and re-dressing. It’s not a huge job, but it’s another thing to stay on top of. A lot of our customers call us when they’re weighing up exactly these points. Why fibreglass makes sense as a lead alternative GRP isn’t trying to replace lead everywhere - it’s just a more practical choice for most domestic flat roofs: Much lighter, so less stress on the structure. No scrap value once it’s installed - thieves generally leave it alone. Excellent durability in UK weather when installed correctly (our marine-grade resins handle the rain, wind and temperature changes well). Low maintenance - a properly done fibreglass roof will easily give you 25–40+ years with minimal fuss. Faster to install than traditional lead work, which means less disruption and often lower labour costs. Getting the traditional look with simulated lead trims The biggest concern most people have is appearance. Will it actually look right? With pre-formed simulated lead trims you can get very close to the classic dark lead finish. The C100/C150 flashing trim and matching C7 internal and external corners are designed specifically for this. They’re heavy-duty fibreglass, easy to fit, and give that traditional aesthetic without the weight, cost or theft risk of real lead. Plenty of customers have used them on period garages and extensions and been really happy with how they blend in. C100 Simulated Lead Flashing product page What does a fibreglass kit actually cost? This is where fibreglass usually comes out ahead. Entry-level GRP kits start from around £25 per m² for materials on a basic 10m² setup. Heavier 600g matting, fire-rated options or premium single-coat systems cost more, but they still tend to work out more favourably than a full traditional lead replacement once you factor in speed and lower ongoing costs. For the latest pricing across different kit types and sizes (including current promotions), check our dedicated GRP & EPDM Roofing Kit Cost Per m² guide. Professional installation for GRP is also competitive and normally completes quicker than equivalent lead work. Practical next steps Here’s the thing, whether you’re doing it yourself or getting a local tradesperson in to help, it all comes down to proper prep and good detailing on the edges and trims. Rush that bit and you’ll usually regret it later. Our kits have everything you need in the box. We’ve also got straightforward video tutorials that walk you through fitting the trims, laying up the matting and putting the topcoat on step by step. If the roof gets walked on a lot or has quite a few pipes and upstands, go for the heavier 600g matting. It gives you that extra strength where it matters. Thinking about making the switch? If you’re staring at an expensive lead roof replacement, fibreglass is well worth considering. It’s practical, theft-resistant, and with the right trims it gives you the look you want without the traditional headaches. Use our roof kit calculator to get a quick idea of what you’d need for your roof size. Or have a browse of the simulated lead trims and full GRP kits. If you would like to discuss your roof in more detail, please call us on 0800 612 7903. We are happy to help. You can also use the live chat on the site or email us if you prefer.
