How to check your roof for solar yourself (a DIY walkthrough)

You can size up your own roof for solar before you speak to a single installer, using nothing but your phone, your eyes, and ten minutes across a sunny day. This is the hands-on version: how to read your roof's direction, spot the shading that actually costs you, rough-measure the usable space, and judge from an aerial view whether it's worth pursuing. It won't replace a survey, and it won't be as quick or as precise as an instant estimate, but it teaches you what a surveyor is looking at, so you walk into quotes knowing what you've got.

If you'd rather skip the manual work and get a modelled read in about a minute, do that first (or alongside): our free roof check estimates your roof's direction, sunlight and usable area from your postcode and gives you a Solarable Report. This guide is for when you want to check it yourself, by hand, and understand the why behind the answer.

The four things you're actually checking

Every roof assessment, DIY or professional, comes down to four questions. Keep these in mind as you go:

• Direction (orientation): which way does the roof slope face?
• Shading: what casts a shadow on it, and when?
• Usable space: how much clear, unbroken roof is there for panels?
• Structure and condition: can the roof carry an array, and is it in good enough shape?

You can get a solid read on the first three yourself. The fourth needs a professional, and we'll be honest about where that line sits.

Step 1: Check the direction with a compass or phone

Direction is the single biggest factor you can measure yourself, and it's easy.

• Open the compass app on your phone (every phone has one, or a free one).
• Stand facing the same way your roof slope faces, so you're looking "downhill" along the slope, in the direction the panels would point.
• Read the bearing.

Interpreting it:

• South (around 180 degrees) is the ideal, the highest annual generation.
• South-east to south-west is excellent, close to south.
• East or west (around 90 or 270 degrees) is very workable in 2026: an east-west roof spreads generation across morning and evening and typically gives a strong share of a south roof's output. More on that in the best roof direction for solar panels.
• North (around 0/360 degrees) is the one direction that usually struggles on its own. If that's your main slope, check whether you have a second pitch facing a better way. See solar panels on a north-facing roof.

If your house has two main slopes (a typical front-and-back pitched roof), check both. Many homes end up putting panels on more than one face.

Step 2: Watch the shading across the day

This is the step people skip, and it's the one a surveyor cares about most, because shade hurts solar disproportionately. Shade on even one panel can drag down a whole wired string, so a shadow that seems minor can cost real generation.

You can't measure this from a single glance. Do it properly:

• On a sunny day, look at your roof (from the garden, the street, or an upstairs window) at three times: mid-morning, midday, and mid-afternoon.
• Note what throws a shadow onto the roof slope at each time: trees, chimneys, dormers, aerials, and neighbouring buildings.
• Pay special attention to the south and west of the roof, where the generation-heavy midday and afternoon sun comes from.
• Remember the seasons: the winter sun sits much lower, so a tree or building that's clear in summer can shade the roof in winter. And deciduous trees leaf up in summer exactly when you want the sun.

A roof that's clear at all three checks is a strong sign. A roof clipped by a big evergreen at midday is a real concern worth flagging early. This day-long shadow picture is exactly what a desktop tool reads least perfectly, which is why shading is where an on-site survey earns its keep.

Step 3: Rough-measure the usable space

You don't need to climb up. You're after an approximate area of clear, unbroken roof, because that's what sets how many panels fit.

• As a rule of thumb, a modern panel is roughly 1.7m by 1.1m, so about 1.9 square metres each, and a typical 4 kWp system (around 10 panels) needs roughly 20 square metres of clear roof.
• Estimate your roof slope's width and length from the ground (pace out the footprint of the house, and account for the slope), or measure the footprint on an aerial map (Step 4) and adjust for pitch.
• Subtract the obstructions: chimneys, roof windows, vents, and the gaps panels need around edges all eat into the usable area.

You're not producing a panel layout, just answering "is there clearly enough room for a worthwhile array, or is this a small/broken-up roof?" If ten panels' worth of clear space is obviously there, you're in good shape. If the roof is chopped up by dormers and rooflights, note it.

Step 4: Read your roof from above

An aerial view pulls Steps 1 to 3 together and often reveals things you can't see from the ground. Open a free satellite map (any mapping app with a satellite layer) and find your house:

• Confirm the direction you measured, by seeing which way the ridge line runs and which way each slope faces.
• See the whole shape: the true footprint, both slopes, and how the obstructions are arranged.
• Spot nearby shading: tall trees and neighbouring buildings show up clearly from above, though the image can't tell you when their shadow lands, which is why Step 2 still matters.

This is also exactly what our roof check automates and improves on: it pulls your aerial view, then uses Google's solar data to mark each roof section by direction and modelled sunlight, rather than leaving you to judge it by eye. If you want the machine-read version of this step, that's where to get it.

Get the modelled estimate (the canonical next step)

Doing the DIY check teaches you your roof. The fastest way to turn that into an actual suitability read, direction, sunlight, a Solarable Score, and an honest savings range, is our free tool. It's the natural next step once you've eyeballed the roof yourself:

→ Check if your roof is suitable for solar. Enter your postcode and house, confirm your home on the map, and get a Solarable Report in about a minute. No email, no phone number, no lead form.

It models the same four factors you've just checked by hand, but with per-roof sunlight data behind it, so you get a range for your roof rather than a national average. Then the savings calculator turns it into an estimated annual benefit.

When to stop and get a survey

A DIY check and a desktop estimate both answer the same question: is this worth pursuing? They're the filter, not the verdict. If your roof looks strong or possible, you've saved yourself guesswork before spending a phone call. If it looks difficult, you've learned that early and cheaply.

What neither you nor a desktop tool can settle, and a survey must:

• Whether the roof structure can carry the weight of an array.
• Exact shading across the full day and across the seasons.
• The condition of tiles, battens, and flashing.
• Your consumer unit and where an inverter and (if fitted) a battery can go.

So treat your own check as the confident starting point, not the final answer. We always recommend a full survey from an MCS-certified installer before you commit. When you're ready, our installer directory lists MCS-certified installers covering your postcode.

Frequently asked

Can I really check my own roof without any tools? Mostly, yes. A phone compass, your own eyes across a sunny day, and a satellite map get you a solid read on direction, shading, and usable space. The one thing you can't self-assess is the roof's structure and condition, which is a survey job.

How accurate is a DIY check? Good enough to decide whether to pursue solar, not good enough to buy on. It tells you if your roof is promising; a modelled estimate refines it, and an installer survey confirms it.

My roof faces north. Is it pointless? Not always, especially if you have a second pitch facing east, west, or south. Check both slopes in Step 1. See solar panels on a north-facing roof.

Related

• Solar panels by roof type: slate, tile, terraced, bungalow, garage
• Is my roof suitable for solar? (get your estimate)
• What's the best roof direction for solar panels?
• How much sun does my roof get?
• Do solar panels work on cloudy days?
• Are solar panels worth it in the UK?
• Find listed installers covering your postcode