Can I put solar on an extension roof?

Yes — extension roofs are often ideal (new, structurally sound, can be designed for optimal solar orientation). Flat extension roofs use tilt frames for perfect angle.

Will builders damage my existing panels?

A reputable builder will arrange for panels to be temporarily removed by an MCS installer before work begins. Cost: £500-£1,000. Never let builders move panels themselves.

Should I increase my system size after extending?

Usually yes — extensions increase electricity consumption (lighting, heating, appliances). Adding 2-4 extra panels during reinstallation is cost-effective (saves on scaffolding).

Do I need new planning permission for solar after extending?

If your extension is under permitted development: the solar panels are also usually permitted development. If you needed planning for the extension: mention solar in the application.

Solar Panels and Home Extensions

By Home Solar Guide Team|Updated 18 March 2026|guide

Independently written | Evidence-based | Sources cited

Solar panels extension — Plan solar around your extension — bigger roof = bigger system = more savings.

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Should I install solar before or after an extension?

Planning a home extension? Here is how solar panels fit in: SCENARIO 1 — No solar yet: Install solar AFTER the extension. Why? The extension may increase your roof area (more panels) and your electricity consumption (bigger savings). Design the extension roof with solar in mind — optimal pitch and orientation. SCENARIO 2 — Existing solar: Panels may need moving if the extension affects the roof. Moving cost: £500-£1,000 for scaffolding + electrician. Consider upgrading panels during the move (newer panels = more watts per m²). SCENARIO 3 — Extension flat roof: Great for solar — flat roofs use mounting frames at optimal 30-35° tilt. KEY RULE: Tell your architect and installer about solar plans before design sign-off.

Frequently Asked Questions

Related: Home Heating Systems

Solar panels are most powerful when combined with an efficient heating system. Heat pumps use solar-generated electricity to heat your home at 300-400% efficiency — making them the ideal partner for solar.

heat pump running costs in the UK

Heat pumps use electricity at 300-400% efficiency, making them ideal partners for solar.

From our sister site Home Heat Pump Guide