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Barking and Dagenham, London

SAP calculations in Barking and Dagenham

SAP calculations in Barking and Dagenham are the energy assessments building control may ask for when a house is extended or a new home is built. We coordinate the assessor and fit the result to your drawings. Fixed quote after a free constraints check, VAT included.

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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 sap calculations

    Five 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. Independent check

      A second chartered technologist checks every sheet against the council's validation checklist and the policy. A senior review signs it off before anything is submitted.

    4. Building regulations

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

    5. 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

    SAP calculations in Barking and Dagenham: the local picture

    The energy rules are national, but the shape of the homes they are applied to is local. In this borough 68.8 per cent of households live in a house or bungalow, so most of our work here is on houses that are extended at the back, at the side or in the roof. That is exactly the case where the choice of compliance route matters.

    The council's own guide for such work is the Residential Extensions and Alterations SPD, and its estate-specific one is the Becontree Estate SPD and Design Code. Both concern how a building looks and sits. Neither sets energy figures, which is why the SAP and the planning design have to be reconciled by us, not left to chance.

    Wall build-ups are where the two meet. A planning elevation that shows a thin, flush wall may be impossible once the insulation required by the energy rules is added, so we check the thickness at the design stage and adjust the layout, not the specification, when something has to give.

    Red-brick English house with rows of solar panels on its tiled roof

    Local figures for Barking and Dagenham

    Figures with their unit, period and source
    MeasureValuePeriodSource
    Households living in a house68.8 % of households living in a house or bungalow (detached, semi-detached or terraced)Census 2021nomisweb.co.uk
    Householder applications granted66.5 %1 July 2025 - 30 June 2026assets.publishing.service.gov.uk
    Article 4 directions3 Article 4 directions published by the council—planning.data.gov.uk
    Conservation areas4 named conservation areas published by the council—planning.data.gov.uk
    Larger home extension prior approvals refused36 decisions2025 Q2 to 2026 Q1 (1 Apr 2025 to 31 Mar 2026)assets.publishing.service.gov.uk
    Average house price375,604 GBP2026-07publicdata.landregistry.gov.uk
    Approved Document L Vol 1 2021 incl. 2023 amendments, Table 4.2New 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—gov.uk
    Approved Document L Vol 1 2021, para 10.7(d)Windows, roof windows, rooflights and doors in an extension should not exceed 25% of the extension floor area plus the area of openings removed or covered—gov.uk
    Circular 01/2026 (transitional arrangements)AD L/F 2021 continue where plans/notices are deposited before 24 Mar 2027 and work starts before 24 Mar 2028—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 Barking and Dagenham
    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

    Choosing the route for a Barking and Dagenham extension

    Approved Document L allows more than one way to show an extension is efficient. The plain limits for new parts of a house are: 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. If the design meets them and the glazing stays inside its cap, no calculation is needed.

    The cap on glazing is spelled out: Windows, roof windows, rooflights and doors in an extension should not exceed 25% of the extension floor area plus the area of openings removed or covered. A kitchen extension on a typical garden with folding doors across the back can sit close to that line, so we count the glass on the plans before a supplier is chosen.

    When the design cannot meet the limits, the alternatives are listed as: Alternative routes: area-weighted U-value (para 10.9) or a SAP calculation against a notional extension (para 10.10). A SAP comparison lets us keep a feature window by improving the roof or floor, which is often cheaper than changing the architecture.

    Planning context for energy work in the borough

    Barking and Dagenham decided 388 householder applications in its latest published year, granting 66.5 per cent. A third of applications falling short makes it worth submitting drawings that are complete and consistent, and the energy information is part of that consistency.

    There are 3 Article 4 directions and 4 conservation areas, which can restrict external changes such as replacement windows. A restriction like that limits how far glazing can be improved on a front elevation, and the calculation then has to carry the load elsewhere.

    For larger home extensions the national return shows 10 prior approvals granted and 36 refused. Where that route is open, we draw the scheme first and run the energy figures second, so neither delays the other. Our planning drawings in Barking and Dagenham page sets out the options.

    New homes and the changing energy rules

    A new dwelling is assessed on a different basis. The guidance says: For new dwellings AD L 2026 names two methods: the Home Energy Model (HEM) and SAP; validity dates are in the Notice of Approval. Which edition applies depends on when plans are deposited, and the date is stated as: AD L 2026 takes effect 24 Mar 2027 (24 Sep 2027 for higher-risk building work).

    Projects already in the system are protected by the transitional rule: AD L/F 2021 continue where plans/notices are deposited before 24 Mar 2027 and work starts before 24 Mar 2028. For a flat conversion or a new house on a large plot, we put both dates on the programme so the energy method is fixed before the building notice goes in.

    A new home also needs a certificate once built. In plain terms: An energy performance certificate is required on construction of a new dwelling. The design-stage figure is the prediction and the certificate is the record, so the specification on the drawings must be built as drawn.

    Cost, timing and the other work around the calculation

    A SAP calculation is priced separately from the drawings because the work ranges from a short check to a whole-dwelling assessment. You receive a fixed quote after a free constraints check, VAT included, before committing to anything.

    The assessor works from our model, so floor areas, walls and windows match the drawings. The sheets then feed the technical submission described in building regulations drawings in Barking and Dagenham and the beam design in structural calculations in Barking and Dagenham.

    Average prices in the borough are £375,604, and the market has moved 5.3 per cent over twelve months. Extra insulation is a small slice of what an extension costs, and we would rather settle it early than rework a wall on site. For the wider picture see architectural drawings in Barking and Dagenham.

    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
    Energy in
    Move the pointer up — the plug rises toward the socket.

    Other services in Barking and Dagenham

    SAP calculations nearby

    Questions

    Does an extension in Barking and Dagenham always need a SAP calculation?

    No. If the new walls, roof, floor and openings meet the limits and the glazing stays within its cap, the simple route is enough. A SAP calculation is the fallback when they do not.

    Which local guidance affects my extension design here?

    The council's Residential Extensions and Alterations SPD covers design. Energy limits come from Approved Document L, and we reconcile the two.

    What are the glazing limits for an extension?

    The guidance says: Windows, roof windows, rooflights and doors in an extension should not exceed 25% of the extension floor area plus the area of openings removed or covered.

    How much does it cost?

    Fixed quote after a free constraints check, VAT included. It depends on whether the job is an extension check or a new dwelling.

    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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