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Wandsworth, London

MEP design in Wandsworth

MEP design in Wandsworth is the services design for a borough of high-value Victorian terraces, where owners often extend into the loft, the rear or the ground below: the council's Housing SPD covers all four. We design heating, ventilation, electrics and water so the finished space is comfortable and quiet. 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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    Pencil resting on a dimensioned technical drawing beside a scale rule

    What Wandsworth's guidance and the London Plan require

    The Wandsworth Local Plan 2023-2038 was adopted in 2,023. The council's Housing SPD (covers rear extensions, basements, roof extensions and loft conversions) sits beneath it, and a separate piece of Basement extensions guidance (non-statutory) deals with excavation. Together they are why services design in Wandsworth often starts below the ground floor or above the first: a basement needs drainage that works against gravity, and a loft needs its own ventilation and cooling.

    The plan's energy policy asks for an energy assessment with every new home, logged as Energy assessment: all new residential, so a flat conversion needs one while a loft on an existing house does not. The overheating policy sets out a London Plan SI4 cooling hierarchy. We use it as the working order for loft conversions, whose roofs take the sun all afternoon: reduce what enters, limit internal gains, use mass where possible, ventilate naturally and mechanically, and only then add cooling.

    For a householder these two policies become two paragraphs and one table in the design note, written in plain English and kept with the drawings.

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

    Local figures for Wandsworth

    Figures with their unit, period and source
    MeasureValuePeriodSource
    LP10 para E: all new residential development and major non-residential development must submit an energy assessment following the London Plan energy hierarchy (validation item 11 repeats this; the Council's Sustainability Checklist is local guidance). Major schemes also need a Whole Life Cycle Assessment.Energy assessment: all new residential—wandsworth.gov.uk, Wandsworth Local Plan 2023-2038 (adopted 19 July 2023), LP10 para E, printed p.289 (PDF p.303); validation list p.12, item 11
    LP10 para H: new development must minimise overheating through layout, design, construction, materials and landscaping, following the London Plan cooling hierarchy (Policy SI4); para 15.24 onwards explains the hierarchy.London Plan SI4 cooling hierarchy—wandsworth.gov.uk, Wandsworth Local Plan 2023-2038 (adopted 19 July 2023), LP10 para H, printed p.290 (PDF p.304); para 15.24, printed p.293
    Owner-occupied households42.5 % of households owner-occupied (owned outright or with mortgage/loan)Census 2021nomisweb.co.uk
    Average price, terraced970,844 GBP2026-07publicdata.landregistry.gov.uk
    Conservation areas46 named conservation areas published by the council—planning.data.gov.uk
    Listed building entries312 list entries (Historic England, within the LPA boundary)—planning.data.gov.uk
    Householder applications granted91.9 %1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Larger home extension prior approvals granted13 decisions2025 Q2 to 2026 Q1 (1 Apr 2025 to 31 Mar 2026)assets.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 Wandsworth
    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

    Basements and the plumbing that fights gravity

    A basement bathroom or kitchen sits below the level of the street sewer, so waste cannot run out by gravity. The usual answer is a sealed pump chamber with a non-return valve, which we show on the drainage schematic with the discharge route, the alarm and the maintenance access. We also design mechanical ventilation, because a basement habitable room relies on it more than any other room in the house.

    Electrics matter as much. Sockets, lighting and underfloor heating are laid out before the screed, and the consumer unit is chosen to carry them. Where the structure needs a waterproofing system we agree the service penetrations with the structural engineer so nothing is cut afterwards.

    Lofts, plant and a tight plan

    In a roof conversion the cylinder, the ventilation unit and the water tank all compete for the same cupboard. Approved Document F sets whole-dwelling ventilation by bedroom, for example 31 litres per second for three bedrooms and 37 for four. Adding a loft bedroom raises that figure, so the ventilation unit has to be sized for the finished house.

    A heat pump is designed for a maximum flow temperature of 55 degrees Celsius, which affects emitter and cylinder size. In an old terrace the cylinder may be bigger than the cupboard. We test alternatives such as a slimline unit or a hybrid with the existing boiler, and cost each one plainly.

    Extension fabric limits sit at 0.18 W/m²K for walls and 0.15 for roofs.

    Value, heritage and the borough's planning record

    A terraced house here averages £970,844 and a detached house £2,495,892, while prices moved -5.5 per cent in twelve months. At those values, owners invest in the house instead of moving, and 42.5 per cent of the borough's 137,393 households own their homes.

    The borough has 46 conservation areas and 9 registered parks and gardens. Historic England lists 312 buildings, of which 5 are Grade I and 34 Grade II*, and 8 are on the risk register. Equipment on a street frontage inside a conservation area is normally avoided, and we place flues and units at the back.

    In its latest year the council decided 977 householder applications, granted 91.9 per cent and decided 92.4 per cent in time. For larger home extensions through prior approval, the returns show 13 granted and 12 refused. These are planning figures, used for timing only.

    Wandsworth levies £1,031.39/m² (Nine Elms Residential Area A); £475.34/m² (Nine Elms Residential Area B); £0 (Roehampton Charging Area); £448.43/m² (all other areas) under its own schedule, and Mayoral CIL is charged at an indexed £96.97 per square metre in the borough's band.

    What we supply and where to go next

    A Wandsworth package has a heating and hot-water strategy, a ventilation layout with flow rates, power and lighting plans, a water and drainage schematic including any pump chamber, and plant locations. A second MCIAT technologist checks the set. The fee is fixed after a free constraints check.

    Read architectural drawings in Wandsworth for the borough overview, or the national MEP design page. The services pair with building regulations drawings in Wandsworth and SAP calculations in Wandsworth. Nearby, see MEP design in Kingston upon Thames and 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.
    House extension under construction with scaffolding, new glazed doors and building materials
    Every layer specified
    Move across to open the layers; move down to pick one.

    Other services in Wandsworth

    MEP design nearby

    Questions

    Does a Wandsworth flat conversion need an energy assessment?

    Yes. The rule is logged as Energy assessment: all new residential. A loft on an existing house adds no dwelling, so it falls outside.

    Can a basement bathroom drain by gravity?

    Usually not, because the sewer is higher. A sealed pump chamber with a non-return valve lifts the waste, and we draw it on the schematic.

    What does the cooling hierarchy mean for a loft?

    It is the London Plan SI4 cooling hierarchy, applied in order from shading through to mechanical cooling as a last resort.

    How much does MEP design cost in Wandsworth?

    Fixed quote after a free constraints check. The price depends on whether the project is a loft, basement or full retrofit.

    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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