Solar Panels on Slate Roofs

Why slate needs more care

Slate is thin, brittle and fixed with nails rather than hung on a nib. Anchors have to be placed carefully and the slate dressed or replaced around them. A rushed job on slate shows up as cracked slates and, eventually, water ingress.

The Derby context

Much of the older housing here is Victorian terraces, interwar and post-war semis, and modern estates, with clay tile and slate on the older stock, concrete interlocking tile on later housing. Derby's post-war semis tend to have shallow-pitch roofs, which changes the mounting detail and can make an east-west split array the better option.

Fixing detail

Anchors fix to the rafters, with the slate above dressed over the bracket or replaced with a lead soaker. Done properly there is no reliance on sealant to keep the water out.

Age and condition

Old slate can be sound for decades more or can be at the end of its life with failing nails. A survey should include a genuine assessment of that, because it changes the sequencing of the whole job.