I've been looking into installing solar panels on my flat roof, but I'm worried about the high winds in my area. A few installers said it wouldn't be cost-effective because of the roof height and wind conditions, so we decided to go with a battery system and a hybrid inverter instead. Now, I'm considering a DIY approach since the inverter is already installed. I want to avoid penetrating the flat roof for water-proofing reasons and I'm not keen on using ballast since it could blow away in the wind.
My flat roof is in the south of the UK, measuring 7.8m by 3.6m with a single-ply membrane.
I'm thinking of two options:
1. Mounting three 500w panels vertically on the southwest-facing wall of the house using unistrut. This could cost about £300 and seems easy enough. It won't generate a lot but would help with topping up the battery in the afternoons/evenings.
2. Gluing rigid or flexible panels directly onto the flat roof membrane to minimize wind load. I know flat panels aren't optimal for generation or cooling, but I think it might be better than having no panels. However, I haven't found much information on this method and I'm curious if it's a bad idea. Any advice or suggestions would be great!
3 Answers
You definitely shouldn't glue or use VHB tape to attach them to the roof. If you ever need to remove the panels, it can damage the roof. A better method is to bond a plastic sheet with embedded bolts to the roof and then screw the panels to that for easy replacement. This method works well for smaller setups like vans, but roofs have different challenges. Also, why not just set some panels up in the garden if that’s feasible?
I would seriously consider installing the panels on the wall instead. If you're mounting them vertically, wind won't be an issue and you'll likely find a more stable structure to attach them to, which also helps prevent leaks.
Gluing panels directly to the roof isn't recommended at all. There's really no way to calculate how well they’ll hold up under pressure, especially with wind. Instead, you could build mounting points beneath the roof—like metal struts attached to your walls that reach up to the roof. This way, you wouldn't penetrate the membrane but still would have a solid hold.
Thanks for the advice! I attached a photo of my roof for better context. It’s tricky to connect to the walls since it’s a dormer with hung tiles.