Is your roof suitable for solar?

Most UK roofs suit solar. That is the honest headline, and it is why the question is usually answered with a shrug and a quote request. But "most" is not "all", and the difference between a roof that works well and one that barely pays is worth ten minutes of your time.

We are an MCS-certified installer and we have turned down jobs — so this guide includes the cases where the answer is no. Work through the five checks below and you will know roughly where you stand before anyone visits.

1. Which way does your roof face?

This is the single biggest factor, and the one people worry about most unnecessarily.

• South — the best case. Everything else is measured against it.
• East or west — typically around 80–85% of a south-facing roof. Fitted every week. An east–west split spreads generation across morning and evening, which can suit a working household better than a midday peak.
• South-east or south-west — very close to south. No real concern.
• North — not worth doing on its own.

How to check: open the compass app on your phone, stand facing the same way as the slope of your roof, and read the bearing. Or find your house on a map app — north is up.

2. What shades it, and when?

Shade costs more generation than most people expect, because panels wired together in a string can be dragged down by the weakest one. Modern designs get around this with optimisers or micro-inverters, so each panel works independently — but the shade still costs you whatever light it blocks.

How to check: look at the roof at 9am, midday and 4pm on a clear day. What matters is the middle of the day. A chimney shadow that crosses the array at 8am is a detail; a neighbouring building over it at 1pm is a design problem.

Trees are worth a separate thought, because they grow. A sapling that clears your roof today may not in ten years, and the system is meant to last twenty-five.

3. How steep is it?

Around 30 to 40 degrees is close to ideal in the UK, and most pitched British roofs sit in or near that range. This is rarely the thing that stops a job.

Flat roofs work too — extensions, garages and dormers are all usable with tilt frames that angle the panels properly and space them so one row does not shade the next. We have done exactly that on a Romford job where the flat rear extension carried as much of the system as the main roof. Our flat roof and garage guide covers it in detail.

4. What condition is the roof in?

There is no age limit on a roof, only a condition test — and it is the check most likely to change our advice.

Panels are warranted for 25 years. If the roof underneath needs replacing in three, you would be paying to remove and refit the array later. It is far cheaper to re-roof first and then fit solar. We will say so at survey when we see it, even though it delays the job.

Signs worth noticing yourself: slipped or missing tiles, sagging between rafters, damp patches in the loft, or a roof that was already old when you moved in.

5. Is there enough clear space?

A typical panel is about 1.7 metres by 1.1. Ten panels need roughly 20 square metres of clear roof once edge margins are allowed for.

What eats into that: chimneys, roof windows, vents, aerials, valleys where two slopes meet, and anything that breaks the rectangle. This is exactly why a rule of thumb is not a design — two roofs of the same size can take very different numbers of panels. Our sizing guide works through it from your bill.

When we say no

Four situations where we will tell you not to proceed, or not yet:

• The roof needs replacing first. Do that, then call us.
• The only usable slope faces north and there is no alternative elevation.
• Heavy permanent shade across the middle of the roof through the middle of the day.
• Too little usable space for a system that would justify the scaffolding and the paperwork.

None of these are common. But a company that never says no is not being straight with you, and a survey that only ever ends in a quote was never really a survey.

Planning permission and leases

For most UK houses rooftop solar is permitted development and needs no planning application. The exceptions worth knowing:

• Listed buildings — consent is needed.
• Conservation areas — street-facing slopes need care; rear slopes are usually fine.
• Flats and leasehold — freeholder or landlord consent is often required.

We check your specific address during the free design rather than leaving you to find out later.

What a proper answer looks like

Everything above gets you to a sensible expectation. What it cannot do is tell you how many panels fit, what they will generate, or what it costs — those need your actual roof measured and your actual electricity use.

That is what our free design does, usually back within 24 hours. If the answer is that your roof is not worth doing, we will tell you that too. What a system costs once it is worth doing is set out in our pricing guide.

Published 25 August 2026 by ECONEXIS, MCS-certified installers based in Chadwell Heath, Essex.