Roof inspected
The tile type, roof condition, structure, pitch and mounting requirements are established.
Solar roof fixing and leak risk explained
Can solar panels damage my roof or cause leaks?
This is one of the most understandable worries a homeowner can have.
You are taking a roof that currently keeps Scotland's rain outside, putting engineers on it and attaching several hundred kilograms of equipment that may remain there for decades.
You are entitled to know exactly how that is supposed to be done without creating a future leak.
The short answer
Properly installed solar should not make your roof leak.
But solar installation is real construction work.
Roof coverings are lifted or worked around, structural fixings are installed, rails are attached and people move across the roof.
Poor workmanship can therefore cause damage.
The correct promise is not “a leak is impossible”.
It is that a competent installation should preserve the roof's ability to keep water out, and the mounting system should be designed specifically to achieve that.
Tom Solar visual guide
What is actually happening underneath the solar panel?
How panels stay on the roof
The solar panels are not relying on the roof tiles to hold them down.
A rooftop solar array needs to transfer its weight and wind forces safely into the building.
The exact fixing depends on the roof type and certified mounting system.
A common above-roof arrangement is:
structural attachment or roof hook;
mounting rail;
module clamps;
solar panel.
The roof covering keeps the weather out. The structural mounting system holds the solar array down.
A typical tiled-roof installation
Think underneath the tile, not through the middle of it.
Covering accessed
Tiles are carefully lifted or removed where the mounting attachments need to be installed.
Structural fixing installed
The attachment is fixed to the appropriate structural member or suitable substrate according to the certified mounting design.
Weathering restored
The tile is repositioned and, where required by the system, correctly notched, dressed or otherwise weathered around the fixing.
Rails installed
Aluminium mounting rails are fixed to the roof attachments.
Panels clamped down
The modules are secured to the rails using compatible clamps in the positions specified by the mounting and module manufacturers.
“Do you drill through my tiles?”
Not in the crude way homeowners often imagine.
People often picture an installer putting a panel on top of a tile, drilling straight through it and filling the hole with silicone.
That is not a useful model of a proper pitched-roof installation.
Certified mounting systems use purpose-designed roof attachments and weathering arrangements appropriate to the roof type.
Be suspicious of improvised waterproofing.
MCS 012 specifically addresses weather-tightness and does not simply treat a blob of site-applied sealant as a substitute for a properly designed weatherproof fixing system.
Slate roofs
Slate needs respect — especially old Scottish slate.
Natural slate can be extremely durable, but it can also be brittle and unforgiving when disturbed.
The fixing method must therefore be suitable for the particular roof.
Depending on the certified system, the installation may use:
purpose-designed slate brackets;
slate hooks or structural attachments;
appropriate flashing;
replacement weathering components;
and carefully formed openings around the attachment.
Slate is not just “another type of tile”. The installation method should recognise what is actually on the roof.
What about broken tiles?
Accidental damage should be identified and corrected — not hidden under the array.
Roof tiles can crack during construction work.
That possibility is precisely why good installation practice matters.
A damaged tile should be replaced or correctly repaired using an appropriate roofing method before it becomes inaccessible beneath the array.
“The panels will cover it anyway” is not an acceptable waterproofing strategy.
The roof covering beneath the array still has to perform as a roof.
Roof hooks and tiles
The bracket should not become a pressure point that cracks the covering.
MCS requirements specifically address brackets used with fragile coverings such as slate, clay and concrete tiles.
The mounting design must avoid damaging loads on the roof covering, or demonstrate that any permitted load is distributed without causing damage.
This is why bracket clearance and correct tile detailing matter.
A fixing that presses incorrectly onto a tile can turn movement, snow load or foot traffic into a future crack.
Wind loading
The panels do not only push down on the roof. Strong wind tries to pull them off.
Solar panels create an additional surface above the roof.
Wind flowing around the building can create significant uplift.
The mounting design therefore has to consider:
property location;
building height;
roof pitch;
roof dimensions;
array position;
roof edge zones;
mounting-system capacity;
and the number and spacing of fixings.
More panels do not simply mean more weight. They also mean a larger structure exposed to the wind.
Why roof edges matter
Wind forces can become more severe around the perimeter of the roof.
Current MCS guidance normally keeps modules away from the domestic roof edge unless specific additional measures are taken.
Where panels are installed close to an edge, the design may need:
additional fixings;
additional structural timber;
specific uplift calculations;
consideration of ridge security;
rainwater run-off;
and snow shedding.
Roof margins are not merely cosmetic.
They can be part of the structural, weather and maintenance strategy.
The roof itself
A good solar installation starts by asking whether the roof deserves another 25–30 years of service.
There is little sense installing a long-life solar array over a roof that is already near the end of its useful life.
Before installation, look for:
cracked or slipped tiles;
missing or damaged slates;
failed flashing;
sagging roof lines;
rotted or damaged timber;
previous water staining;
condensation or damp;
significant historic alterations;
and other signs of structural distress.
Fix the roof first when it genuinely needs fixing.
Removing and reinstalling an entire solar array several years later to replace a failing roof is avoidable expense.
Structural assessment
Solar adds permanent load to a structure that may already be 50, 80 or 100 years old.
Current MCS requirements say the roof structure should be checked by a suitably competent person to confirm it can withstand the loads introduced by the PV system.
More unusual roofs can require structural-engineer involvement.
Warning signs can include:
structural distress;
removed or heavily notched timbers;
major post-construction alterations;
unusual hips or valleys;
significant snow traps;
or construction that cannot be confidently assessed using normal methods.
What can actually cause a leak?
Usually something has gone wrong — either before, during or after installation.
Existing roof defect
A failing tile, flashing detail or underlay problem may already exist before the solar installation begins.
Broken covering
A cracked tile or slate that is not replaced can allow water into the roof construction.
Poor bracket detailing
Incorrect clearance, displacement or badly executed weathering can compromise the roof covering.
Wrong mounting product
A fixing intended for one roof type should not be improvised onto another.
Poor penetrations
Cable and fixing penetrations must be detailed using appropriate, durable methods.
Later disturbance
Roofing work, satellite installation, chimney work or other later trades can disturb tiles or solar mounting details.
The pre-installation survey
This is where much of the risk should be removed.
Before the installation team arrives, somebody should understand the roof.
Useful evidence can include:
wide roof photographs;
close photographs of the covering;
roof dimensions;
roof pitch;
ridge, hip and valley details;
chimneys, vents and roof windows;
visible damaged coverings;
loft structure where safely accessible;
rafter or joist information where relevant;
signs of historic water ingress;
and access constraints.
Photographs taken before installation are valuable evidence.
They record the condition of the roof before work begins and help the installation team arrive knowing what they are dealing with.
Survey first, sell second
Sometimes the right answer is “not until the roof is repaired”.
That can be frustrating when the homeowner wants solar immediately.
But installing over a defective roof simply stores up a more expensive problem.
A survey has value when it is allowed to say “no”.
A genuinely independent assessment should be capable of recommending:
repair first;
obtain a roofer's opinion;
seek structural engineering advice;
modify the panel layout;
or use a different roof face.
Existing roof warranties
New-build and recently replaced roofs deserve an extra check.
If the roof covering is still under warranty, the solar work may affect its terms.
Current MCS requirements say the roof warranty provider should be consulted where the existing covering is under warranty.
If the proposed installation may invalidate that warranty, the customer should be explicitly informed.
Do not discover this after the panels are installed.
Ask before work begins whether any builder, roofing or new-home warranty needs approval or notification.
Bird protection
Mesh should protect the array — not become another source of roof damage.
Bird mesh can be useful around rooftop solar because pigeons and nesting debris can create maintenance problems beneath modules.
But the mesh should be installed using a method compatible with the panel frame and mounting arrangement.
It should not be an excuse for random new holes in the roof covering.
The purpose is to protect the system without compromising the roof or module frame.
If a leak appears later
Do not immediately assume the panels are guilty — but do not ignore the timing either.
Water can travel surprisingly far through a roof before appearing on a ceiling.
The visible damp patch may not be directly below the original entry point.
If a leak appears:
photograph the damage;
record when it appears and weather conditions;
do not climb onto the solar array yourself;
contact the installer;
provide any pre-installation roof photographs;
and obtain competent roof/solar investigation if necessary.
Diagnose first. Blame second.
Warning signs in a quotation or survey
Things that would make me ask more questions.
| What you hear | What I would ask next |
|---|---|
| “It fits any roof.” | Which mounting system is being used and is it certified for my actual roof covering? |
| “We don't need to see the loft.” | How has the roof structure been assessed? |
| “A little silicone seals it.” | What is the certified weathering method for this mounting system? |
| “The roof is probably fine.” | What evidence has actually been recorded about its condition? |
| “We can put panels right to the edge.” | Show me the wind-uplift design and additional measures being used. |
| “Don't worry about that cracked slate.” | Why is a known roof defect being covered instead of corrected? |
Frequently asked questions
Solar panels and roof leaks answered.
Can solar panels cause roof leaks?
Poor installation or damage can cause leaks, but a correctly designed and competently installed PV system should maintain the roof's weather-tightness.
How are panels fixed to a tiled roof?
Purpose-designed roof attachments connect the solar mounting structure to the appropriate roof structure or substrate. Rails attach to those fixings and the panels are then clamped to the rails.
Are panels simply screwed through the tiles?
No. Proper pitched-roof systems use attachments and weathering arrangements designed for the particular roof covering rather than treating an ordinary tile as the structural fixing.
What about slate?
Slate requires a suitable slate mounting method. Brackets, flashing and replacement weathering details vary with the certified system.
Can mounting brackets crack tiles?
Poorly selected or incorrectly fitted brackets can. Certified systems and correct installation detail are intended to avoid damaging loads on fragile roof coverings.
Should the roof be inspected first?
Yes. Condition and structural suitability should be established before a long-life solar array is installed.
What if my roof needs work already?
Repairing or replacing the affected roof first may be much more sensible than paying to remove the solar array again a few years later.
Can wind lift the panels?
Solar mounting systems must be designed for wind forces including uplift. Fixing quantity and spacing depend on the building, location, roof and array position.
Does solar invalidate my roof warranty?
It can depend on the warranty terms. Where a roof is still under warranty, the provider should be consulted before installation.
What should I do if I get a leak afterwards?
Record the evidence and contact the installer. A competent investigation should determine whether the cause is the solar work, an existing roof defect or something unrelated.
Can bird mesh damage the roof?
Properly installed bird protection should not require inappropriate roof penetrations or compromise the mounting system.
What should a good roof survey show?
It should provide enough evidence to understand the roof covering, condition, dimensions, pitch, structure, obstacles, visible defects, access and the fixing method the installer will need.
Standards checked
Keeping the rain out is not an optional extra.
This homeowner guide was reviewed against current material including:
- MCS MIS 3002 Solar PV Systems — Issue 6.0, March 2026.
- MCS 012 — Pitched Roof Installation Kits.
- MCS requirements covering weather-tightness, structural assessment, roof coverings and wind uplift.
- UK Health and Safety Executive guidance on roof work and fragile surfaces.
- Scottish Building Standards principles relating to structure, fire and environmental protection.
Roof types and mounting products vary considerably. The certified mounting-system instructions, structural assessment and property-specific installation design take precedence over the simplified examples in this homeowner guide.
Related Tom Solar guides
Understand the roof before deciding what goes on it.
Tom Solar view
You should know what is happening to your roof before anybody climbs onto it.
Solar panels can remain in place for decades.
That means the roof underneath deserves at least as much attention as the shiny equipment going on top.
Before awarding the work, ask:
What condition is my roof actually in?
What mounting system is being used?
What is it fixing into?
How is weather-tightness maintained?
How have wind loads been considered?
What happens if damaged tiles or slates are discovered?
What evidence will I receive afterwards?
A solar survey should reduce uncertainty before the contract is signed.
The homeowner should not have to simply cross their fingers and hope the roof is suitable.