Mounting & placement
Ballasted solar mounts: weighted, no-drill mounting
A ballasted mount holds a panel down with weight rather than bolts, so it needs no holes drilled into a roof or ground. That makes it appealing for flat roofs and removable setups — but the weight and wind maths have to add up.This guide explains how they work and where they fit. For all the options, see the mounting systems hub.
Written and edited by Christopher Panteli
Christopher is the founder and editor of MyPlugInSolar. He oversees the site’s research standards, data tools and editorial process. He is not an electrician or solar installer, and specialist technical claims are sourced from official documentation or reviewed by appropriately qualified professionals.
How ballasted mounting works
Instead of bolting a frame down, a ballasted mount uses a tray or frame loaded with weight — concrete blocks, paving slabs or filled trays — to hold the panel against wind. It's the standard way to put solar on a flat roof without piercing the waterproof membrane, and it works on the ground too as a free-standing base. The angled frame sets the tilt, much like other ground-mounted and flat-roof approaches.
The weight and wind trade-off
The appeal — no holes — comes with a constraint: the only thing stopping the panel lifting or sliding in a gust is the ballast. Too little and it can move in high wind; too much and the roof or surface may not take the load. An angled panel acts like a sail, so the wind exposure of the site matters as much as the panel itself.
Safety and compliance
Where ballasted mounts suit plug-in solar
As with any mounting, this is about the hardware — plug-in solar is not yet legal to use in the UK (legal status).
- Flat roofs and outbuildings where you don't want to drill the membrane.
- Gardens and yards where a free-standing, movable base is useful.
- Rented or temporary setups you may want to remove — see plug-in solar for rented homes.
- Situations where a fixed bracket into structure isn't possible or wanted.
Frequently asked questions
- What is a ballasted solar mount?
- A mounting system that holds a panel down with weight — blocks, slabs or filled trays — instead of bolts. It avoids drilling, which is why it's common on flat roofs, and it relies on enough ballast to resist wind uplift.
- Are ballasted mounts safe in high wind?
- They can be, if the ballast is correctly sized for the site's wind exposure and the surface can carry the load. An angled panel catches a lot of wind, so under-ballasting is dangerous — follow the manufacturer's guidance and get professional advice where exposure or roof loading is uncertain.
Sources
- 1. BS 7671 Requirements for Electrical Installations (IET Wiring Regulations) — Institution of Engineering and Technology
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