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City of London, London

MEP design in City of London

MEP design in the City of London means heating, ventilation, power and water for a home inside the Square Mile, where only 4,914 households live and almost none of them in a house. We design the systems for flats, conversions and the occasional listed home, then draw them into one model. Fixed quote after a free constraints check.

Fixed quote after a free constraints check

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    Architectural model of a four-storey London stucco townhouse in its terrace, with a portico, area railings, sash windows, a cornice and chimney stacks
    The house as it stands: four storeys over a lower ground floor.Existing Proposed worksAn illustrative model, built for this page.

    How we work on mep design

    Four steps from first call to approval.

    The same model cut through the middle: every floor, the stair, the chimney breasts, the new mansard, rear extension and basement in section
    Section through the model: every floor on one datum.

    1. Enquiry and constraints check

      We check the property against conservation areas, listed status, Article 4 directions, tree preservation orders, flood zone and planning history. We choose the right route and send a fixed quote.

    2. Measured survey

      We survey the house on one datum: rooms, levels, boundaries, drains, trees and the neighbours' windows that the 45° and 25° tests depend on.

    3. Building regulations

      Technical drawings are coordinated with the structural engineer's calculations, the drainage and the planning conditions.

    4. Approval and hand-over

      Building control approval, then a next-steps pack covering the commencement notice, party wall timing and CIL.

    Free redraws until approval. Every drawing set is checked independently, and the checker is never the person who drew it.

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    Two-storey rear extension under construction on a semi-detached house

    The City's own rules for MEP design

    The City follows the London Plan on the two policies that shape building services. The first is water. Development should be conditioned so that mains use stays within 105 l/p/d (+ up to 5 l external), which is the optional standard in the Building Regulations. Taps, showers, cisterns and any dishwasher or washing machine allowance are chosen against that figure, so it is set on the first schedule of the design rather than discovered at completion.

    The second is overheating. Major schemes must show a cooling hierarchy, 6 steps, from reducing the heat that enters the building to active cooling only as the last step. The plan says the same thinking can be applied to smaller projects, and for a flat on a south-facing upper floor it is sensible to follow it. Solar-control glazing, blinds, a purge route and quiet mechanical extract all come before an air-conditioning unit, which in a listed or conservation setting is also the hardest item to place.

    A planning officer in the City reads those two policies against a proposal that is usually a refurbishment, not a new house. So our design note answers them in plain terms: the water budget per person, the cooling steps taken and why each later step is or is not needed.

    House extension under construction with scaffolding, new glazed doors and building materials

    Local figures for City of London

    Figures with their unit, period and source
    MeasureValuePeriodSource
    London Plan Policy SI 5C(1): development proposals should, through planning conditions, limit mains water use to the Building Regulations optional requirement, 105 litres or less per head per day for residential development, excluding an allowance of up to 5 litres for external use. Applies in every London borough.105 l/p/d (+ up to 5 l external)—london.gov.uk, The London Plan 2021 (GLA, March 2021), p.356, Policy SI 5 part C(1)
    London Plan Policy SI 4B: major development must show through an energy strategy how internal overheating and reliance on air conditioning are reduced, following the six-step cooling hierarchy (reduce heat entering; minimise internal heat generation; manage heat with thermal mass; passive ventilation; mechanical ventilation; active cooling). Para 9.4.1 says the principles can also be applied to minor development.cooling hierarchy, 6 steps—london.gov.uk, The London Plan 2021 (GLA, March 2021), p.354, Policy SI 4 part B and para 9.4.1
    Conservation areas28 named conservation areas published by the council—planning.data.gov.uk
    Listed building entries637 list entries (Historic England, within the LPA boundary)—planning.data.gov.uk
    Households living in a house2 % of households living in a house or bungalow (detached, semi-detached or terraced)Census 2021nomisweb.co.uk
    Owner-occupied households36.5 % of households owner-occupied (owned outright or with mortgage/loan)Census 2021nomisweb.co.uk
    Householder decisions1 decisions1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Minor applications granted97.1 %1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Mayoral CIL rate (indexed)96.97 £/m² (indexed, permissions granted in 2026)—london.gov.uk
    AD L Vol 1 (2026) para 4.10, PDF p.51; 2021 edition para 5.10, PDF p.4655 degC—gov.uk

    A blank value means the figure has not been published, not that there are none. Check your own address with the council.

    Councils bordering City of London
    Building regulations, layer by layerPart A: structure: Approved Document A: Structure, 2004 edition incorporating 2004, 2010 and 2013 amendments. Part B: fire safety: All dwellings: fire detection and alarm system minimum Grade D2 Category LD3 (BS 5839-6), mains-operated smoke alarms to BS EN 14604. Part L: insulation: New elements in existing dwellings, limiting U-values W/(m²·K): roof 0.15, wall 0.18, floor 0.18, windows 1.4 (or WER Band B), doors 1.4. Part K: stairs: 2.0 m clear headroom over stairs. Full plans application: Building control body must decide a full plans application within 5 weeks, or longer if agreed in writingPart A: structurePart B: fire safetyPart L: insulationPart K: stairsFull plans applicationABCDE

    Building regulations, layer by layer

    The Approved Documents that shape most house projects, from structure to the application itself.

    A · Part A: structure
    Approved Document A: Structure, 2004 edition incorporating 2004, 2010 and 2013 amendments
    B · Part B: fire safety
    All dwellings: fire detection and alarm system minimum Grade D2 Category LD3 (BS 5839-6), mains-operated smoke alarms to BS EN 14604
    C · Part L: insulation
    New elements in existing dwellings, limiting U-values W/(m²·K): roof 0.15, wall 0.18, floor 0.18, windows 1.4 (or WER Band B), doors 1.4
    D · Part K: stairs
    2.0 m clear headroom over stairs
    E · Full plans application
    Building control body must decide a full plans application within 5 weeks, or longer if agreed in writing

    A borough of flats, towers and old fabric

    Only 2 per cent of households here live in a house or bungalow, and 36.5 per cent own their home. The typical MEP job is therefore a flat, a live-work unit or a conversion in a building that already has risers, plant rooms and a managing agent.

    That changes the design questions. Where does a new bathroom extract duct run when the riser belongs to the freeholder? Can a heat pump condenser sit on a roof the lease does not demise? Can a second consumer unit be added without upgrading the incoming supply? We find the answers in the lease, the building's operating manual and a short survey, and we state our assumptions on the drawing so an installer can confirm them before pricing.

    On the Barbican, the Barbican Estate Listed Building Management Guidelines: Volume I Introduction and Volume II Residential (SPD) sets the limit on what can change in a listed residential estate. Services that pass through concrete, penetrate a facade or alter a balcony are controlled strictly, so the design keeps new routes inside existing ducts and floor voids wherever it can.

    Heritage that decides where plant can go

    The Square Mile has 28 conservation areas and Historic England lists 637 buildings in it: 86 at Grade I, 82 at Grade II* and 445 at Grade II. There are also 53 scheduled monuments and 5 entries on the Heritage at Risk Register.

    For an MEP designer those numbers mean a flue terminal, an air-source unit or a new vent grille is rarely a free choice. We check the list entry, mark any external item on the elevation and flag early when it will need listed building consent or a separate planning application. Internally, we try to keep to the existing service routes and avoid chasing into historic plaster, floors or panelling.

    Planning decisions are mostly for commercial work. The council decided 477 applications in its latest published year, including 173 minor ones, and granted 97.1 per cent of those. It recorded just 1 householder decision, so a home project here is unusual and we treat the statistics as background, not a forecast.

    Money, energy and the numbers on the drawings

    The average flat in the City sold for £709,939, and the borough sits in the highest Mayoral CIL band with an indexed rate of £96.97 per square metre for permissions granted this year. The council also charges its own levy, set by zone. Those costs sit alongside the services budget, and new floor area from a mezzanine or roof extension can trigger them.

    On the technical side we design to Approved Document L, with limiting wall values of 0.26 W/m²K for a new dwelling and 0.18 for an extension wall. A heat pump is designed for a maximum flow temperature of 55 degrees Celsius. Ventilation follows Approved Document F, which asks for 25 litres per second for a two-bedroom home.

    What we supply and how we price it

    A City package normally has a heating and hot water strategy, a ventilation layout with flow rates, power and lighting plans, a water and drainage schematic, a plant location plan and an overheating note. Everything is drawn into the same model as the architecture so that clashes show up on screen. See how the sheets join the building regulations drawings for the same address.

    We do not publish a starting price, because a one-bedroom flat refit and a whole-building scheme are far apart. After a free constraints check you receive a fixed quote. A second MCIAT chartered technologist checks the set before it leaves us.

    Related services in the Square Mile

    For the wider picture read architectural drawings in City of London, or the national version of this service on the MEP design page. The sheets that show the layouts are our M&E drawings in City of London, and the energy and sustainability statement is covered under building services design. For a neighbouring borough, see MEP design in Tower Hamlets, Hackney or Southwark.

    What you receive

    Building regulations section drawing showing the construction build-up
    Sample drawing. Building regulations section showing construction build-up for a building control check.
    Brick house being extended, with a wide new opening supported over the ground floor
    Every layer specified
    Move across to open the layers; move down to pick one.

    Other services in City of London

    MEP design nearby

    Questions

    What water limit applies to MEP design in the City of London?

    The London Plan asks for mains water use to be limited to 105 l/p/d (+ up to 5 l external). We set the fittings schedule against that figure.

    Does a City flat need a cooling hierarchy?

    Major schemes must show one. The plan says smaller schemes can apply the same cooling hierarchy, 6 steps, and we do so for any flat with high solar gain.

    Can I fit a heat pump on a City roof?

    Often yes, but the lease, the structure and the list entry all matter. We check them before drawing the unit, and design for a flow temperature of 55 degrees Celsius at most.

    How much does MEP design cost in the City of London?

    Fixed quote after a free constraints check. The figure depends on the size of the flat or building and the systems you want.

    Sources and dates

    City of London skyline glowing at dusk across the Thames under a dramatic orange sky

    Tell us about your property.

    We check the constraints, then send a fixed fee. Messages before 3pm get a reply the same working day.

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