020 7864 7245Request a fixed quote

Bexley, London

MEP design in Bexley

MEP design in Bexley suits a borough of family houses: 75.3 per cent of households live in a house. We design the heating, ventilation, electrics and water that make an extension or loft comfortable, and draw them with the architecture. Fixed quote after a free constraints check.

Fixed quote after a free constraints check

  • MCIAT chartered
  • £2m PI insured
  • LABC Partnered
  • Fixed fees, VAT included

Request a fixed quote

We use it to check conservation areas and constraints.
Pick the council that decides your application.
A few lines: what you want to build, and anything the council has already said.
Add photos or drawings

Drop files here or choose from your device

PDF, JPG, PNG, DWG · up to 10 files, 90 MB in total

    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.

    Request a fixed quote
    House extension under construction with scaffolding, new glazed doors and building materials

    London Plan rules that reach a Bexley house

    For services, the rules that matter most in Bexley come from the London Plan. The first is its water policy, which expects conditions limiting mains use in homes to 105 l/p/d (+ up to 5 l external). The national default is 125 litres per person per day, so the London figure is a tighter budget for taps, showers and cisterns.

    The second is overheating. The policy asks major development to show how internal heat and reliance on air conditioning are reduced, and its own summary is: cooling hierarchy, 6 steps. A Bexley semi-detached with a new loft is not a major scheme, yet an attic bedroom under a dark roof is where the problem shows first, so we apply the same steps in a lighter form.

    In practice that means reducing heat entering through glazing and roof design before any fan or cooling is considered. A rooflight facing south gets solar-control glass or an external blind point, a dormer gets openable windows on opposite faces, and mechanical ventilation comes last.

    Brick house being extended, with a wide new opening supported over the ground floor

    Local figures for Bexley

    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
    Households living in a house75.3 % of households living in a house or bungalow (detached, semi-detached or terraced)Census 2021nomisweb.co.uk
    Green Belt share of the council area17 % of council area covered by green-belt polygons—planning.data.gov.uk
    Householder applications granted94.6 %1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Larger home extension prior approvals granted7 decisions2025 Q2 to 2026 Q1 (1 Apr 2025 to 31 Mar 2026)assets.publishing.service.gov.uk
    Larger home extension prior approvals refused8 decisions2025 Q2 to 2026 Q1 (1 Apr 2025 to 31 Mar 2026)assets.publishing.service.gov.uk
    Lawful development certificate applications (PS1)323 certificates2025 Q2 to 2026 Q1 (1 Apr 2025 to 31 Mar 2026)assets.publishing.service.gov.uk
    AD L Vol 1 (2026) para 4.10, PDF p.51; 2021 edition para 5.10, PDF p.4655 degC—gov.uk
    AD L Vol 1 (2021 incl 2023) Table 4.2, PDF p.35; 2026 edition Table 3.20.18 W/(m2.K)—gov.uk
    AD S (2021) para 6.2, PDF p.357 kW—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 Bexley
    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

    MEP design in Bexley: semis and the heat pump question

    Bexley has 95,300 households and 68.6 per cent are owner-occupied. Where a house still runs on a gas boiler, the owner's question is often whether to swap to a heat pump during an extension. Because the guidance designs wet heating for a flow temperature no higher than 55 degrees Celsius, the heat loss of every room is calculated first and the radiators, or an underfloor loop in the new room, are sized to match.

    Extensions must meet limiting fabric values: 0.18 W/m²K for walls, 0.15 for roofs and 0.18 for floors. Those numbers decide how small the heat demand of the addition is, and they are why a well-insulated extension often needs only one extra radiator or a short underfloor zone.

    Ventilation follows the same logic. A new sealed room needs a planned route for air, and the guidance sets 31 litres per second for the whole of a three-bedroom home. We lay out extract points, supply routes and the duct runs against the joists shown on the plans.

    Green belt, gardens and plant positions

    Green belt covers 17 per cent of the borough, and the council's Design Guide, in Design Guide SPD Part 1: Design Principles and Design Guide SPD Part 2: Building Alterations and Extensions, shapes extensions across the rest. Outside plant such as an air source heat pump is usually positioned in the rear garden, away from the boundary and from a bedroom window next door, and its pipe route is drawn from the start.

    Detached homes sell at a premium here: the average detached house sold for £736,523 in the latest figures, against £416,198 for a terrace. A larger roof may have space for solar panels, so the electrical design includes the inverter, isolators and a consumer unit with spare ways.

    Where there is parking, a charge point is part of the design. The guidance defines it with a nominal output of at least 7 kW, and the cable, protective device and load check are decided at design stage, not left to the electrician.

    What Bexley's planning record means for the drawings

    Bexley decided 877 householder applications in the latest twelve months published, granted 94.6 per cent and decided 99.4 per cent in time. With decisions arriving on time, a complete drawing set is worth the effort, including the position of plant and flues on the elevations.

    The larger home extension prior approval route saw 7 granted and 8 refused. If you use it, show flues, vents and condensers on the plans so the neighbours' consultation sees them.

    Owners also tested permitted development through 323 lawful development certificate applications in the same year. Our lawful development certificate service covers the route, and the MEP design is then built into the same set.

    How we work and where to go next

    Our building services design page explains the wider package, and our M&E drawings service produces the sheets an installer works from. Both come from one model.

    Bromley, Greenwich and Dartford all border Bexley. See architectural drawings in Bromley or architectural drawings in Dartford to compare the local planning picture.

    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.
    Pencil resting on a dimensioned technical drawing beside a scale rule
    Every layer specified
    Move across to open the layers; move down to pick one.

    Other services in Bexley

    MEP design nearby

    Questions

    What London Plan water limit applies to a new Bexley home?

    The policy expects conditions that limit mains water use to 105 l/p/d (+ up to 5 l external).

    Does a Bexley loft conversion need an overheating assessment?

    The formal requirement is for major development. Its summary reads: cooling hierarchy, 6 steps. We still apply the steps to lofts, because they are where heat builds up.

    Can I add a heat pump when I extend my semi?

    Often, yes. We calculate each room's heat loss, size emitters for a flow temperature of no more than 55 degrees Celsius and place the unit in the garden.

    How much does MEP design cost in Bexley?

    Fixed quote after a free constraints check. We price after seeing the house, the plans 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.

    Request a fixed quoteCall 020 7864 7245WhatsApp