Most UK roofs are suitable. The main reasons a roof fails a solar assessment are poor condition, significant shading, or insufficient space - and all three are identifiable before any money changes hands. A free site survey from an MCS-certified installer covers all of them.
Here's what installers actually look at, and what each factor means for your installation.
Orientation
South-facing roofs produce the most electricity in the UK, capturing the sun as it tracks across the southern sky throughout the day. But east and west-facing roofs generate around 85% of south-facing output - enough to make solar well worth installing in most cases. A southeast or southwest roof sits at around 95% of optimal.
North-facing roofs are the exception. At around 55% of south-facing output, the economics rarely work, and most installers won't recommend it.
If your house has roof faces in multiple directions, a split array - panels on the east and west slopes, for example - can generate more total electricity than a single south-facing array of the same size, with the added benefit of spreading generation across more of the day.
Shading
Shading has a bigger impact on output than orientation. A shaded south-facing roof will underperform an unshaded east-facing one.
The problem with shading on a standard string inverter is that one shaded panel drags down the output of every panel in that circuit. A tree that shadows two panels at 2pm effectively reduces the output of your entire system during those hours. Power optimisers or microinverters solve this by letting each panel operate independently - worth considering if shading is unavoidable.
Installers assess shading during the site survey, including winter sun angles, which are much lower than summer. A tree that casts no shadow in July can shade panels significantly from October to March. Future growth matters too - a young tree 10 metres away may become a problem within five years.
Roof Condition
Solar panels are designed to last 30-40 years. If your roof needs re-tiling in the next 10 years, it's worth doing that first. Removing panels to replace tiles underneath costs more than the original installation work and disrupts the system.
A surveyor checks roof condition as a standard part of the pre-installation assessment. If there are any concerns, they'll flag them before you commit. In most cases, a roof in reasonable condition for a standard house is fine.
Roof Space
A 4kW system - right for most 3-4 bedroom homes - needs around 20m² of usable roof space for 10 panels. Obstructions like skylights, chimneys, and roof vents reduce usable area and need to be worked around in the panel layout.
If roof space is tight, high-efficiency monocrystalline panels (20-24% efficiency) generate more per square metre than standard panels. A smaller system on a well-oriented, unshaded roof often outperforms a larger system on a compromised one.
| System size | Panels needed | Roof space required | Suitable for |
| 3kW | ~8 panels | ~16m² | 1-2 bed homes, flats |
| 4kW | ~10 panels | ~20m² | 3-4 bed semis |
| 6kW | ~14-15 panels | ~30m² | 4+ bed detached |
Roof Material
Solar panels can be installed on most UK roof types. The material affects how the mounting brackets attach, not whether installation is possible.
| Roof type | Suitability | Notes |
| Concrete or clay tile | Excellent | Standard hook-and-rail mounting; tiles lifted and replaced around brackets |
| Slate | Good | Requires specialist slate hooks; slightly higher labour cost |
| Metal (standing seam) | Excellent | Clamps attach without drilling; fastest installation |
| Flat (felt or EPDM) | Good | Ballasted or mechanically fixed frames required |
| Asbestos cement | Not suitable | Disturbing asbestos sheets is a health and legal risk |
| Thatch | Not suitable | Fire risk; no suitable mounting method |
| Timber shake | Not suitable | Fire risk |
Structural Integrity
Solar panels weigh around 10-13kg each, plus mounting hardware. A 10-panel system adds roughly 150-180kg to the roof structure - distributed across multiple rafters rather than concentrated in one point. Most UK roofs built in the last 50 years handle this without any modifications.
Older properties with signs of rafter damage, significant sagging, or previous water ingress may need a structural assessment before installation. Your installer flags any concerns at survey stage.
Flat Roofs
Flat roofs are fully suitable with the right mounting system. Panels sit in angled frames, typically set at 10-35° to capture useful solar generation. Two main approaches:
Ballasted frames use concrete blocks to hold the mounting frames in place without penetrating the roof membrane. These are common on commercial flat roofs and larger residential installations where roof penetration is undesirable.
Fixed frames are mechanically anchored to the roof structure. These suit smaller residential systems and are more wind-resistant for exposed locations.
East-west arrays at a shallow angle (10-15°) are an increasingly popular flat-roof option - two rows of panels facing opposite directions produce a broader generation curve across the day, with lower wind loading than south-facing frames at steeper angles.
Aesthetics and Planning
Most residential solar installations are permitted development - no planning permission required. The exceptions are listed buildings and some conservation areas, where consent may be needed before installation. Your installer confirms this at survey stage.
Panel aesthetics have improved considerably. All-black monocrystalline panels blend into dark slate or tile roofs without the silver-frame contrast of older installations. Building-Integrated Photovoltaics (BIPV) - panels designed to replace roof tiles entirely - are available for projects where conventional panels would be refused or are aesthetically unacceptable, though at higher cost.
In-roof systems, where panels sit flush with the roofline rather than above it, are another option for new builds or full roof replacements where integration is possible from the start.
FAQ
What if my roof has skylights or roof vents? Skylights and vents reduce usable panel area but don't prevent installation. The panel layout works around them. Your installer designs the system around the available space, which may mean a slightly smaller system than your roof area would otherwise suggest.
My roof faces east - is it worth it? At 85% of south-facing output, an east-facing roof produces around 2,900 kWh per year from a 4kW system in Hampshire. At 24.5p/kWh, that's meaningful savings. East-facing systems also generate more in the morning, which suits households with high early-day electricity use. Yes, it's worth it.
How old does my roof need to be for solar to make sense? Solar panels last 30-40 years. If your roof has at least 10-15 years of life left in reasonable condition, installation makes sense. If it's approaching the end of its life, re-roofing first avoids the disruption of removing and reinstalling panels later.
Do I need to reinforce my roof for solar panels? For most UK homes built in the last 50 years, no. The weight of a typical residential system is well within normal roof load tolerances. Properties with damaged rafters, significant roof spread, or visible structural movement may need assessment. Your installer flags any concerns at survey.
Will solar panels invalidate my roof warranty? This depends on your roofing material warranty and the installation method. MCS-certified installers use mounting systems designed to maintain weatherproofing. On tiled roofs, hooks replace the underlay seal at each penetration point. Discuss this with your installer if you have an active roof warranty.
Can I get financial support to help with the cost? 0% VAT applies to all residential solar installations until March 2027. The Warm Homes Plan (which replaced ECO4 in April 2026) provides interest-free loans and, for eligible low-income households, fully funded installations worth up to £30,000.Check your eligibility here.
CRG Direct has installed solar panels across Hampshire since 2017. MCS Certified, HIES Accredited.
Contact us for a free roof assessment and quote. We'll respond within one working day.