From 1 April 2010, owners who generated their own electricity from small solar installations could be paid for it under the new Feed in Tariffs. Installers were already busy, and many homeowners, landlords and managing agents were being offered panels with a promise of a steady income. The panels may last for decades. The roof underneath them has to last as long, and that is where problems start.
Check the roof covering first
Once panels are fixed, any repair to the slates or tiles beneath them means taking the array off and putting it back. If the covering is near the end of its life, it is usually cheaper to renew it before the panels go on. Look at:
- the age and condition of the tiles or slates, and of their fixings;
- the battens and underlay, which are often older than the visible covering;
- flashings, valleys and gutters near where the array will sit;
- signs of past leaks inside the roof space.
Check the structure
Panels and their rails add weight and wind load. Older roofs, particularly those with slender rafters or with timbers altered over the years, may need checking before they carry more. A short inspection of the roof space will show whether rafters have spread, sagged or been cut, and whether the fixings proposed by the installer will find sound timber.
Check permissions and paperwork
- Planning. On many houses, panels can be fitted without a planning application, subject to conditions. Listed buildings need listed building consent, and conservation areas bring extra limits. Ask your council if in doubt.
- Leases. In a block of flats the roof usually belongs to the freeholder. A leaseholder will need consent, and the freeholder should think about future roof repairs before agreeing.
- The installer. To claim the tariff, the system and installer must be registered under the Microgeneration Certification Scheme (MCS). Ask to see the registration.
- Insurance. Tell your insurer, and check the panels are covered.
A sensible order of work
- Have the roof and its structure inspected.
- Carry out any repairs or renewal needed.
- Obtain consents.
- Then fit the panels, ideally while scaffolding is already in place.
Sharing scaffolding between roof repairs and the installation can save a noticeable sum, and it avoids disturbing a newly finished roof.
Our Building Surveys and Defect Diagnosis service covers roof inspections of this kind. For a longer view of roof life within a wider plan, see how we prepared a ten year maintenance plan for a managing agent.