Solar Panel Installation in London

What the installer is actually designing

A solar installation is a system, not a pile of panels. The installer is balancing four things at once: how much roof you have and which way it faces, how much electricity you use and when, what the inverter can sensibly handle, and what the roof structure will carry. Change one and the others move.

In London that usually starts with the roof. The housing here is mostly Victorian and Edwardian terraces, interwar semis in the outer boroughs, and a large stock of converted flats, and the coverings are typically clay and concrete tile, London stock slate, and a lot of flat and butterfly roofs behind parapets. That combination decides the mounting system before anything else is chosen.

The survey

A remote design from aerial imagery is fine for an indicative quote. Before anything is ordered, a good installer will want eyes on the roof: covering and condition, batten and rafter spacing, the state of the flashings, access for scaffolding, the route for cabling, and where the consumer unit sits.

Butterfly and parapet roofs are common on London terraces and often suit a flat-roof frame rather than an on-roof rail system, and large parts of the inner boroughs sit in conservation areas.

Mounting and fixings

On a pitched tile or slate roof the installer lifts tiles, fixes roof anchors to the rafters, seals the penetration, and runs aluminium rails across the anchors. Panels clamp to the rails. Done properly the roof is weathertight and the fixings are into structure, not into batten.

Slate needs more care than concrete tile — it is thinner, more brittle, and less forgiving of a badly placed anchor. Flat roofs use a ballasted or tilted frame instead, with no penetration at all in most cases.

Electrical work

Panels are wired in strings to the inverter, with DC isolation at the array and AC isolation at the inverter. The AC side lands at the consumer unit on its own protected way. Generation metering and monitoring are set up at commissioning.

Earthing and bonding get checked as part of this. If the consumer unit is old or already full, that work may need doing first, and it should appear on the quotation rather than as a surprise on the day.

Grid notification

Most domestic systems are notified to UK Power Networks after the event under G98. Larger systems, or connections where the local network is already constrained, need a G99 application and approval before installation. Your installer handles this; ask which route applies to you before you commit to a date.

Handover

At handover you should receive the MCS certificate for the installation, the system design and performance estimate, the electrical certificate, the manufacturer warranties, the monitoring login and an operation and maintenance manual. Without the MCS certificate you will struggle to get an export tariff, so check it has actually arrived.