For homeowners, the important thing is not necessarily to become an expert in every Approved Document. It is to make sure the installer has properly considered the building as well as the solar equipment.

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Do Solar Panels Need Building Regulations Approval?

 

Building Regulations apply to relevant aspects of a solar-panel installation, but a separate Building Control application is not always required.

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This distinction is important.

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Building Regulations set the standards the work must satisfy. Building Control approval is one route through which compliance can be demonstrated.

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Where work is carried out by somebody registered with an appropriate Competent Person Scheme, certain work can be self-certified instead of the homeowner making a separate Building Regulations application. The installer then provides the relevant certification.

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Where the work cannot be self-certified under an appropriate scheme, or where more extensive structural alterations are involved, Building Control may need to be notified separately.

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The safest approach is therefore to ask the installer before work starts:

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• Which parts of the installation fall under Building Regulations?

• How will the work be certified?

• Is the installer registered to self-certify the relevant work?

• Does the roof require structural assessment or strengthening?

• Will a separate Building Control application be required?

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Do not simply assume that because an installer fits solar panels every day, every aspect of the project automatically falls within a self-certification scheme.

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Part A – Is the Roof Strong Enough for Solar Panels?

 

One of the most important Building Regulations considerations is structural safety.

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Approved Document A deals with the structure of buildings, including the loads acting on roofs. The fundamental requirement is that the structure must safely support and transmit the combined loads imposed upon it.

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Adding solar panels increases the permanent load carried by the roof.

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The assessment should not consider only the weight of the panels. It can also need to account for:

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• Mounting rails

• Brackets and fixings

• Ballast where applicable

• Wind forces

• Snow loading

• Existing roof coverings

• Existing structural condition

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A modern tiled roof in good condition may comfortably accommodate a conventional solar array.

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An older roof, lightweight structure, heavily loaded roof or roof showing evidence of movement or deterioration may require closer investigation.

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Does the Roof Need a Structural Survey Before Solar Panels Are Installed?

 

Not every house needs a full structural engineer's report before solar panels can be installed.

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However, the installer needs to establish that the roof is suitable.

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This normally involves considering the roof structure, condition, spans, supporting members, roof covering and the loads introduced by the proposed solar system.

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Where there is uncertainty, a structural engineer may need to assess the roof.

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This can be particularly sensible where:

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• Rafters are unusually small or widely spaced.

• The roof structure has previously been altered.

• Roof timbers show signs of deterioration.

• A loft conversion has changed the original structure.

• The roof carries heavy coverings.

• A particularly large solar array is proposed.

• Solar panels are being installed on an unusual structure.

• A ballasted flat-roof system is proposed.

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Part A is concerned with the ability of the building to safely sustain the loads imposed upon it.

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Solar Panels on Older Roofs

 

The age of a property does not automatically make it unsuitable for solar.

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Many older buildings have extremely substantial roof structures.

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The issue is condition rather than simply age.

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Before panels are fitted, it makes sense to consider whether the roof covering itself is likely to require replacement during the life of the solar installation.

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Installing a new solar array over tiles or slates that will need replacing shortly afterwards can mean paying to remove and reinstall the panels unnecessarily.

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Any existing structural defects should also be addressed before additional equipment is added to the roof.

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Flat Roof Solar Panels and Structural Loads

 

Flat-roof systems deserve particular attention because they are frequently installed differently from pitched-roof systems.

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Some flat-roof solar arrays are mechanically fixed to the structure.

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Others use ballasted mounting systems, where additional weight helps hold the panels and frames in position without extensive penetrations through the roof membrane.

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While ballast can reduce the need for penetrations, it increases the permanent load on the building.

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The roof therefore needs to be assessed for:

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• Panel weight

• Mounting-frame weight

• Ballast

• Wind loading

• Snow loading

• Existing roof construction

• Existing plant or equipment

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A flat roof should not simply be assumed to have enough spare structural capacity for a ballasted solar system.

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Part P – Electrical Safety and Solar Panels

 

A photovoltaic system is an electrical generating installation, so electrical safety is another central Building Regulations consideration.

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Approved Document P covers electrical safety in dwellings and provides guidance on design, installation, inspection, testing and notification.

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A domestic solar installation can involve:

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• DC wiring from the panels

• An inverter

• AC electrical connections

• Isolation equipment

• Protection devices

• Connection to the consumer unit

• Export metering

• Battery-storage equipment

• Monitoring equipment

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The electrical installation must be safely designed, installed, inspected and tested.

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Does a Solar Installer Have to Notify Building Control?

 

It depends on how the electrical work is being certified.

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Government-approved Competent Person Schemes allow registered tradespeople to self-certify specified Building Regulations work rather than requiring the homeowner to make a separate Building Control application.

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Government guidance specifically recognises that installers registered under an appropriate scheme may be able to self-certify relevant energy-device installations and provide the owner with a scheme certificate.

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If the work is not being carried out through an appropriate self-certification route, Building Control notification may be required.

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This is something homeowners should establish before installation, rather than trying to obtain missing paperwork when the property is later sold.

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What Solar Certificates Should You Receive?

 

The exact documentation depends on the installation and certification route, but the owner should expect suitable electrical and Building Regulations documentation for the work carried out.

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Where a Competent Person Scheme is used, the homeowner should receive certification confirming that the relevant work has been self-certified under the scheme.

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Electrical installation work should also be properly inspected, tested and documented in accordance with the applicable electrical requirements.

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Keep these certificates safely.

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They can become important when:

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• Selling the property

• Remortgaging

• Making an insurance claim

• Altering the solar system

• Replacing the inverter

• Adding battery storage

• Undertaking future roof work

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Missing compliance documents can create unnecessary complications years after the installation has been completed.

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Part C – Keeping the Roof Weatherproof

 

Fixing solar panels to a roof must not compromise the building's resistance to moisture.

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Approved Document C includes requirements and guidance relating to the resistance of roofs, walls and floors to moisture.

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On a pitched roof, panel brackets may interact with tiles, slates, membranes and roof battens.

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On a flat roof, mechanically fixed systems may penetrate the waterproof covering.

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Poor detailing can lead to leaks long after the installer has left.

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Solar installation therefore needs to maintain:

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• Effective roof drainage

• Waterproofing

• Weather resistance

• Appropriate flashings

• Suitable penetrations

• The integrity of membranes and roof coverings

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This is particularly important with older slate roofs and modern flat-roof membranes, where careless fixings can create expensive problems.

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Solar Panels Should Not Simply Be Screwed Through Roof Tiles

 

The mounting system needs to transfer forces properly into the supporting structure.

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Roof tiles and slates are primarily weather coverings; they are not normally the structural element intended to support a solar array.

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Mounting brackets are therefore normally designed to transfer loads to rafters, trusses or another appropriate supporting structure.

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The roof covering then needs to be properly detailed around those fixings to maintain weather resistance.

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A solar installation should not leave cracked tiles, poorly supported slates or makeshift sealant repairs around penetrations.

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Part B – Fire Safety and Solar Panels

 

Fire safety has become an increasingly important part of the discussion around roof-mounted photovoltaic systems.

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Approved Document B contains the principal Building Regulations guidance for fire safety in England, including requirements relating to fire spread across roofs and between buildings.

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Solar installations introduce electrical generation equipment onto or within the roof construction, together with cabling and sometimes energy-storage equipment.

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The government and Building Safety Regulator have been carrying out further research specifically into the behaviour of fires involving roof-mounted solar panels. Research published in late 2025 and early 2026 examined how PV arrays can influence fire spread and thermal exposure to roof coverings.

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This is an area of Building Regulations guidance that is continuing to develop.

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Are New Solar Fire Regulations Coming?

 

Possibly, but it is important not to confuse proposed guidance with rules already in force.

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In March 2026, the government consulted on further changes to Approved Document B, including new provisions specifically addressing photovoltaic panels on roofs.

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At the time of writing in August 2026, those particular proposals should not simply be treated as though they are already the current statutory guidance.

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The existing Building Regulations fire-safety requirements still need to be satisfied, while designers and installers should remain aware that more specific solar-PV guidance is developing.

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For larger residential buildings, apartment blocks and more complex commercial properties, fire-safety considerations warrant particularly careful assessment.

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Solar Panels on Blocks of Flats

 

Installing solar on an apartment building can involve considerably more than installing the same equipment on a detached house.

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Issues can include:

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• Structural roof capacity

• Fire safety

• Access and escape arrangements

• Communal areas

• Shared electrical supplies

• Roof ownership

• Leaseholder and freeholder consent

• Maintenance access

• Firefighter access

• Battery location

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Higher-risk buildings also operate within a more specialised building-control regime.

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For an apartment development, the solar installation should therefore be considered as part of the building as a whole rather than simply treating the roof as unused space available for panels.

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This page should internally link to Solar Panels on Flats.

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Building Regulations for Solar Batteries

 

Battery storage is increasingly being installed alongside solar PV.

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A battery adds another substantial electrical component to the property and therefore needs to be properly designed, positioned and installed.

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Relevant considerations can include:

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• Electrical safety

• Isolation

• Protection equipment

• Ventilation

• Accessibility

• Manufacturer's clearances

• Fire safety

• Cable routes

• Structural support for heavy equipment

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The forthcoming 2026 edition of Approved Document L explicitly addresses on-site electricity generation and energy storage and directs designers to the electrical-safety requirements of Part P and relevant fire-safety guidance. That edition takes effect for most applicable work in England from 24 March 2027, so it should not be confused with the requirements applying to ordinary retrofit projects today.

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Battery design should therefore form part of the installation strategy rather than being treated as an afterthought.

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Part L and Solar Panels

 

Part L deals with the conservation of fuel and power.

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For somebody adding solar panels to an existing house, the issues most commonly encountered during installation are usually structural and electrical rather than Part L being the principal approval route.

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For new homes, however, solar generation is becoming much more closely integrated with Building Regulations energy requirements.

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The new 2026 Approved Document L introduces guidance for on-site renewable electricity generation and takes effect for most relevant projects from 24 March 2027. Earlier editions continue to apply to projects falling under earlier standards.

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This should link internally to your Solar Panels for New Build Homes article, where the new Future Homes Standard can be covered in much greater detail.

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Solar Panels on a New Build

 

Solar panels incorporated into a new house are different from panels retrofitted to an existing building.

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Because the solar installation can be considered during the original Building Regulations design, the architect, structural designer and electrical designer can coordinate:

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• Roof orientation

• Panel layout

• Roof structure

• Fixing locations

• Electrical routes

• Inverter location

• Battery storage

• Heat pumps

• EV charging

• Fire safety

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This can produce a much cleaner installation than trying to introduce all of these systems into a completed house later.

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The forthcoming Part L requirements make this early coordination increasingly important.

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Do Planning Permission and Building Regulations Cover the Same Thing?

 

No.

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They deal with different matters.

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Planning is primarily concerned with whether development is acceptable in planning terms — issues such as appearance, scale, location, heritage and impact on the surrounding area.

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Building Regulations deal principally with technical standards including structure, fire safety, electrical safety, energy and other matters affecting the performance and safety of buildings.

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Government guidance expressly distinguishes Building Regulations approval from planning permission and confirms that some projects can require both.

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For solar panels, this means an installation might be permitted development from a planning perspective but still need to satisfy Building Regulations.

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This article should link prominently to Planning Permission for Solar Panels.

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What Happens if the Roof Needs Strengthening?

 

Occasionally, an assessment may identify that the existing roof should be strengthened before the panels are installed.

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The required solution depends entirely on the structure.

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It could involve strengthening rafters, adding supports, improving connections or undertaking more extensive structural work.

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The important thing is that the solution should be designed around the actual roof rather than guessing on site.

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If structural strengthening itself constitutes controlled building work, the appropriate Building Control procedure should also be followed.

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This is particularly important where installers encounter an old, modified or unusually lightweight roof.

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Does Changing the Roof Covering Affect Building Regulations?

 

Potentially.

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If solar installation forms part of a wider re-roofing project, additional Building Regulations requirements can become relevant beyond the solar installation itself.

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For example, substantial renovation of a thermal element can bring energy-efficiency requirements into play.

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Similarly, replacing or substantially altering roof construction may require consideration of structure, insulation, ventilation, moisture resistance and fire performance.

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If the roof is due for replacement anyway, it can be sensible to coordinate the re-roofing and solar work as one project rather than treating them separately.

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Solar Panels and Roof Warranties

 

A modern roof may have a manufacturer or contractor warranty.

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Before another contractor drills, fixes or modifies that roof, check the warranty conditions.

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This is especially important with:

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• GRP roofs

• EPDM membranes

• Single-ply membranes

• Liquid roofing systems

• Recently completed tiled roofs

• New-build warranty properties

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The solar mounting system should be compatible with the roof construction and should not unnecessarily compromise existing guarantees.

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This is separate from Building Regulations compliance but can be equally important financially.

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Who Is Responsible for Building Regulations Compliance?

 

Building Regulations place responsibilities on those involved in building work, including building owners, designers and contractors.

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The government Approved Documents explain that those responsible for building work must both follow the proper procedures and meet the applicable technical requirements.

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Using an experienced installer does not mean homeowners should ignore compliance completely.

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Before agreeing to the installation, ask how Building Regulations will be dealt with and what documentation you will receive afterwards.

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A reputable installer should be able to answer that clearly.

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What Should You Check Before Installing Solar Panels?

 

Before installation, establish the basic compliance route.

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Check that:

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• The roof has been assessed as suitable.

• Structural capacity has been considered.

• The proposed fixings suit the roof construction.

• Weatherproofing details are appropriate.

• The electrical installation will comply with Part P where applicable.

• The installer can explain how the work will be certified.

• Any required Building Control notification has been identified.

• Fire-safety implications have been considered where relevant.

• Battery-storage requirements have been addressed.

• Planning requirements have been checked separately.

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This does not need to make a domestic solar project unnecessarily complicated.

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It simply means designing and installing the system properly.

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Solar Panels Building Regulations – FAQs

 

Do solar panels need Building Regulations approval?

Relevant parts of a solar installation must comply with Building Regulations. A separate Building Control application may not be necessary where qualifying work is self-certified by an installer registered with an appropriate Competent Person Scheme.

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Do I need a structural engineer for solar panels?

Not automatically. The roof does need to be capable of safely supporting the installation. Where its capacity is uncertain, structural assessment may be necessary. Approved Document A covers structural loading and roof safety.

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Does Part P apply to solar panels?

The electrical installation associated with domestic solar PV needs to meet the relevant electrical-safety requirements. Approved Document P provides the current guidance for electrical safety in dwellings.

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Can the solar installer self-certify the work?

Potentially, if the installer is registered with the appropriate government-authorised Competent Person Scheme for the work concerned.

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Competent Person Schemes allow specified Building Regulations work to be self-certified instead of requiring a separate Building Control application.

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Do solar panels need planning permission as well as Building Regulations?

Possibly. Planning and Building Regulations are separate. Many domestic solar installations can benefit from permitted development rights, but the Building Regulations position still needs to be considered independently.

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Are Building Regulations different for flat-roof solar panels?

The same fundamental requirements apply, but structural loading can be particularly important where ballasted mounting systems are used. Weatherproofing also needs careful attention where roof membranes are penetrated.

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Does adding a solar battery affect Building Regulations?

Battery storage introduces additional electrical and potentially fire-safety considerations. It should be designed and installed as part of the overall energy system rather than simply connected without assessment.

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Do solar panels affect fire safety?

They can. Part B fire-safety requirements remain relevant, and the Building Safety Regulator has recently carried out specific research into the fire behaviour of roof-mounted PV. The government has also been reviewing additional solar-specific guidance.

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Do new build homes have different solar Building Regulations?

Yes. Solar generation is increasingly integrated into the energy standards for new homes. The new 2026 Approved Document L takes effect for most applicable projects from 24 March 2027.

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Installing Solar Panels? Get the Building Right as Well as the System

 

Solar panels may be an electrical technology, but once they are installed on a building they become part of that building.

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A good installation therefore considers the roof structure, electrical system, weatherproofing and fire safety as well as the performance of the panels themselves.

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For most homes this does not need to create a complicated Building Regulations process. An experienced installer should be able to assess the roof, explain the certification route and ensure the relevant work is properly documented.

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The important thing is to establish those requirements before installation rather than discovering afterwards that structural checks, electrical certification or Building Control documentation are missing.

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APN Solar can help you explore your options and connect you with experienced solar installers who can assess your property and provide quotations for a compliant solar installation.

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