Lightning protection system installation
A lightning protection system gives a strike a planned route to earth: metal on the roof to catch it, conductors down the walls to carry it, and electrodes in the ground to spread it out. Without one, the current finds its own way through masonry, timber and wiring, which is how roofs catch fire and stonework splits.
A new system starts with a BS EN 62305 risk assessment, which decides whether the building needs protection and to what class. Published figures put a small church at £3,000 to £4,000 and two recent public installs at £27,000 and £28,084.
- Designed to
- BS EN 62305 parts 2 and 3
- Small church, published guide
- £3,000 to £4,000
- School, public contract
- £28,084
- Then tested
- At least every year
When a new system is the right call
- A risk assessment, your insurer or a building surveyor says the building needs protection and there is none.
- The existing system was installed to the old BS 6651 and has too few down conductors or earths to meet BS EN 62305.
- You are extending, re-roofing or adding a tall element such as a tower, plant, a chimney or rooftop solar.
- The building is tall, isolated, on high ground, or full of people who would struggle to get out quickly.
- There is equipment inside whose loss would stop the business, the school day or a service to the public.
- Previous strikes or near misses have damaged the building, its electrics or its neighbours.
What new systems cost
| Item | Typical figure |
|---|---|
| Small or average church Diocese of Chester guidance, lightning protection | £3,000 to £4,000 |
| Large church or similar building Same guidance, upper figure for a large building | up to £10,000 |
| New system, council building Exeter City Council, February 2026, value as published | £27,000 |
| New system, primary school Southend-on-Sea City Council, August 2025, value as published | £28,084 |
| BS EN 62305 risk assessment Calculation and report, published UK contractor price guides, autumn 2026 | £1,500 to £3,500 |
Where these figures come from
Church figures are from Diocese of Chester guidance, read November 2026. Test prices are typical ranges from published UK contractor price guides, autumn 2026, excluding VAT, read October and November 2026. Firms are not named. Contract values are copied from Contracts Finder or Find a Tender notices, ex VAT where stated, and show the size of real jobs rather than a rate for yours.
What gets fitted, from the roof down
Air termination
Rods, roof conductors or a mesh of tape across the roof, placed so a strike lands on metal rather than on the building. BS EN 62305-3 sets the mesh size and the rolling sphere radius by class: a 5 m mesh and 20 m sphere for Class I, out to a 20 m mesh and 60 m sphere for Class IV.
Chimneys, parapets, rooftop plant and solar arrays sit inside or are bonded to this layer. On historic buildings the air termination is often limited to the tower or spire, which Historic England accepts as giving reasonable protection in most cases.
Down conductors
Tapes or round conductors carrying the current down the outside of the building, usually copper or aluminium, fixed with clips at regular centres. The standard sets their typical spacing by class: every 10 m round the perimeter for Classes I and II, 15 m for Class III and 20 m for Class IV, with one at each exposed corner where possible.
Each down conductor has a test clamp at a reachable height so it can be separated from its earth for the annual test.
Earth termination
Copper-bonded rods driven into the ground, or a buried ring conductor round the building, joined to the down conductors. Historic England notes BS EN 62305's recommendation of an overall earth resistance of 10 ohms or less; where the soil is poor, rods are driven deeper or more are added until the reading comes down.
Rods usually sit in an inspection pit so the connection can be found and tested later.
Bonding and surge protection
Metal services entering the building (gas, water, power, data) are bonded so a strike cannot jump between them. Type 1 surge protection devices at the supply intake are part of that bonding; without them, the system protects the structure but not what is plugged into it.
What separates a good installation
Most problems found on later tests go back to the original install. These are the things to ask about before you sign.
A design, not just a price
A drawing showing the class, air termination layout, every down conductor, test point and earth, based on a written risk assessment. You keep it, and every later tester uses it.
Materials matched to the building
Copper lasts longer; aluminium is cheaper, lighter and more attractive to nobody with a scrap van, but corrodes more readily and cannot go in the ground. On listed buildings the finish and routing matter as much as the metal.
Safe access priced in
Scaffold, a mobile platform or rope access, chosen for the roof and the site. Work at height is often the largest single cost, so it should be a clear line on the quote.
A commissioning test
Continuity and earth resistance readings recorded at handover, with a certificate. These first readings are the baseline every annual test is compared with.
Specialist trade body membership
Insurers and dioceses often ask for an ATLAS member (the Association of Technical Lightning and Access Specialists). Ask which scheme the firm belongs to and check it yourself.
How a new system gets done
Risk assessment
The building, its use, location and contents are run through the BS EN 62305-2 calculation to decide whether protection is needed, and to which class.
Design and consents
A drawing of the system, plus any listed building consent, faculty or landlord approval. Allow longer for churches and heritage buildings.
Install
Earths first, then down conductors, then the roof layer, with bonding to services and surge protection at the intake where specified.
Test and hand over
Each earth and the whole system tested, readings recorded on a certificate, and the drawing and test date handed to you for the next visit.
Questions people ask
How much does a lightning protection system cost?
It depends on the size and height of the building, the class and the access. Church guidance from the Diocese of Chester puts a small or average church at £3,000 to £4,000 and a large building at up to £10,000. Recent public installs were £27,000 for Exeter City Council and £28,084 at a primary school in Southend. Use our cost planner to budget for testing afterwards.
Does my building legally need lightning protection?
No UK law names lightning protection for most buildings. The duty comes indirectly: employers and duty holders must assess risks to people, and electrical systems must be kept safe. If a risk assessment shows a need, or an insurer asks for it, you are expected to act. See lightning protection regulations.
How long does installation take?
Earths and down conductors on a straightforward building can be done in days once access is up. Design, consents and booking access usually take longer than the install itself, especially on listed buildings.
Copper or aluminium?
Copper is longer lasting and is the usual choice below ground and in corrosive air. Aluminium is cheaper and lighter and is common for roof and down conductors. The choice affects cost, appearance and theft risk, so ask the designer to explain theirs.
Will it spoil the look of a listed building?
It need not. Conductors come in finishes that blend with stone or brick and can follow existing lines such as downpipes and quoins. Historic England expects the visual impact to be considered and conservation consent may be needed.
Does a lightning protection system protect my electrics?
Not on its own. The structural system protects the building and the people in it. Surge protection devices protect the wiring and equipment inside, and a full design under BS EN 62305-4 covers both.
Get a new system assessed and priced
Three quick screens: the postcode of the building, the work, then your contact details. Most people finish in about two minutes.
We are an introduction service, not a lightning protection contractor. We tell you which specialist covers your building before anything is shared, and no one calls you unless you agree.
Thanks, your enquiry is in.
- We aim to tell you within one working day which specialist we suggest for your building.
- Nothing is sent to them until you give the go-ahead.
- They check the building and its system and send you a written price. We will not send you marketing.