Adding EV charging to an existing car park: the civils side

Adding electric vehicle charging to a car park you already own sounds like a small job. Pick a charge point supplier, choose how many bays, book an installer. That can be a fair description of a small 7kW or 22kW workplace scheme where the existing supply has headroom and the cable routes are short. It is not a safe assumption for a bank of rapid or ultra-rapid chargers in an occupied commercial car park.

On those higher-power schemes, the connection, cable routes, bases, drainage, accessibility and phasing can set the programme and move the budget as much as the charging equipment itself. The unit may be fixed to its base quickly. Establishing how much power is available and building a safe route to the bays can take much longer. This article is about that rapid and ultra-rapid end of the retrofit market.

The charger is only one line on the page

Rapid and ultra-rapid charge point hardware is a material cost and becomes more expensive as power, connector capacity and supporting equipment increase. It is still only one part of the installed cost. The rest can include a new or upgraded network connection, trenching and ducting, switchgear, surface reinstatement, manufacturer-specific bases, drainage alterations, bay works and accessibility measures.

Our EV charging civil works guide breaks that scope down by charger power tier. There is no universal percentage split: the balance depends on charger power and quantity, existing electrical headroom, the connection point, cable-route length, ground conditions and whether network reinforcement or a substation is required. Price the equipment, connection, electrical installation and civils as one coordinated scheme.

Power can be the long pole: the DNO connection

The electricity supply is a major programme risk on a high-power retrofit. A small workplace installation may fit within the existing capacity, particularly where load management can limit peak demand. A bank of DC rapid chargers is more likely to need a new or upgraded connection from the local distribution network operator (DNO), and larger hubs may need a dedicated substation.

Define the charging duty, diversity and maximum import requirement first, then check the existing supply and engage the DNO early. A desktop budget estimate is generally free and non-committal, but a formal connection application or quotation may carry assessment and design charges. Straightforward low-voltage work may be delivered in weeks or months; network reinforcement, legal agreements and high-voltage work can extend the programme by many months or longer. Treat every timescale as site-specific until the connection offer is accepted.

Ordering equipment before the load requirement and connection route are understood can leave hardware waiting for power. Let the confirmed connection strategy, not a generic lead-time assumption, set the procurement and construction programme.

Trenching and reinstatement: the part tenants notice

Once you know where the power is coming from, the cable has to get from the supply point or feeder pillar to every bay. On an occupied car park that often means cutting into live tarmac, although routes through verges, existing ducts or trenchless crossings may reduce disruption. This is where a high-power EV retrofit becomes a groundworks and logistics problem as well as an electrical installation.

The cable route needs designing properly: duct sizes, depths, draw pits, separation from other services and warning measures, all to the relevant electrical, DNO and project standards. Before anyone breaks ground on a site that has been in use for decades, obtain service records, locate and mark buried services and use safe digging practices under the HSE’s guidance on avoiding danger from underground services (HSG47). A utility survey is useful evidence, but it does not replace locating equipment, trial holes and a safe system of work.

Every trench then has to be reinstated to a specification suited to the pavement and traffic loading. Poor compaction, unsuitable backfill or a weak saw-cut detail can leave settlement, cracking and trip hazards after the installer has left.

Bases, bollards and the bays themselves

Free-standing charge points and associated switchgear typically need reinforced concrete bases sized to the manufacturer’s details. Where the site risk assessment identifies a credible vehicle strike, the layout may also need kerbs, wheel stops or impact protection positioned without obstructing accessible routes. Public bays need suitable dimensions, markings, gradients and surfaces. None of that is complicated in isolation, but it has to be coordinated with the cable entries and equipment clearances before concrete is placed.

There is also a question the brochure rarely raises: can the existing pavement accommodate the proposed work? The assessment should cover equipment and barrier foundations, draw pits, altered drainage falls and any change in vehicle use, particularly on fleet or van charging sites. Check the pavement and subgrade before the layout is frozen rather than after a bay begins to settle.

Drainage and accessibility are civils decisions, not afterthoughts

Two things routinely surprise clients late in the day. The first is drainage. A like-for-like retrofit within existing impermeable parking bays may add little runoff, but new hardstanding, changed levels, raised plinths and altered kerb lines can interrupt existing falls or create ponding. In England, where Part H applies, Approved Document H gives one route to compliance for surface-water drainage. Where planning approval is required, the authority may also impose sustainable drainage (SuDS) conditions. Our SuDS compliance guide explains the usual design questions.

The second is accessibility. PAS 1899:2022 is a voluntary specification for accessible public charging, but it may be required by a client’s brief, a planning condition, a funding agreement or a procurement framework. Its civil-engineering implications include bay and access-zone dimensions, gradients, firm surfaces, step-free routes and the relationship between kerbs, bollards, cables and controls. Other requirements depend on the charge point hardware and user interface.

Public charge point operators must separately comply with the Public Charge Point Regulations 2023, including the applicable rules on pricing, contactless payment, reliability, helplines and open data. Those regulations do not make PAS 1899 mandatory, but accessible design is far cheaper to coordinate before the bays are built than to retrofit later.

Consents, Part S and who carries the duty

In England, under Part 2, Classes D and E of the General Permitted Development Order, as amended in 2025, installing wall-mounted outlets or charging upstands in an area lawfully used for off-street parking can fall within permitted development rights, subject to limits on the equipment, location and heritage status. Those rights do not apply within the curtilage of a listed building or on a scheduled monument. They generally do apply in conservation areas, although an Article 4 direction, the setting of a heritage asset or associated infrastructure outside the permitted development right may still require planning advice. Sites elsewhere in the UK need advice under the relevant national planning regime.

On a leasehold site, review the lease, demise, rights over the car park and cable route, then obtain the consents required from the landlord, freeholder or other rights holders before work starts. Approved Document S is relevant in England to new buildings, certain material changes of use and major renovations. It does not apply merely because unrelated minor building work is taking place elsewhere on the site.

There is also a legal point that fragmented procurement can miss. This is construction work, so the Construction (Design and Management) Regulations 2015 apply. The CDM client is the organisation for whom the project is carried out, which might be the landowner, tenant, charge point operator or another commissioning party depending on the contractual arrangements. Where there is more than one client, the parties can agree in writing which client will carry most client duties, but every client retains duties to cooperate and provide relevant information.

The HSE’s guidance for commercial clients sets out the core requirements: make suitable management arrangements, appoint organisations with the necessary skills and capability, provide pre-construction information and allow adequate time and resources. The duties apply proportionately even on a small retrofit. We gave our own view on how CDM 2015 works day to day in our response to the CIOB’s review of the regulations.

Grants can change the sums

Before the design is fixed, check whether the intended use qualifies for current support. At the time of writing, the OZEV Workplace Charging Scheme is available until 31 March 2027 and covers up to 75% of eligible purchase and installation costs, capped at £500 per socket and 40 sockets across an applicant’s sites. Once issued, a voucher is valid for 180 days and the installation and claim must be completed within that period. The former staff and fleets and commercial landlord schemes closed to new applications on 31 March 2026.

The Workplace Charging Scheme requires approved equipment and an authorised installer, and its technical rules cover the electrical installation while requiring consideration of BS 8300 accessibility. It is not a general grant for every public charging hub. Confirm the current scheme, site use and approval before procurement because grant terms can change.

Sequence it, then phase it

The order of operations is what separates a smooth retrofit from an expensive one. Define the charging duty and load profile, survey the existing supply and buried services, then engage the DNO early where additional capacity may be needed. Design the connection, cable routes, bases, drainage, accessibility and equipment clearances as one coordinated package rather than resolving clashes on site.

Then phase the works so the car park keeps trading: bay by bay where practical, with a documented traffic-management plan, clear pedestrian segregation and out-of-hours working where a site cannot afford to lose parking during business hours.

Do that and the lowest tender rate per metre may not produce the lowest overall scheme cost. The real cost of an EV retrofit is decided by how well the connection, the groundworks and the disruption are managed, not by the rate on the ducting alone.

Planning EV charging for your car park?

If you are an estate manager, facilities manager, or developer looking at adding charging to a car park you already run, the sensible first step is to scope the civils and the connection before you commit to hardware. Our EV charging civil works guide is a good place to size the job, and our utility connections work covers the supply side. You can see how we are set up to be added to a supply chain on our work with us page, or get in touch to talk through a specific car park and where the real cost and lead time sit.

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Rospower Projects is a specialist groundworks and civil engineering contractor working across the South East and the wider UK, delivering EV charging civils, utility connections, and external works for commercial car parks and estates. Contact us to discuss your project.