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Design & Planning Services

Compliance calculated.
Profit protected.

Nine design-stage services covering every regulated aspect of your new build, extension, or conversion — from SAP to water usage. Early engagement, clear advice, no surprises at completion.

Part L SAP Calculations & EPC Part L SBEM Calculations Part O Overheating Assessments Planning Energy Statements Part L / F Heat Loss Calculations BS EN ISO U-Value Calculations BS EN ISO PSI-Value Calculations Part G Water Usage Assessments Part L Overglazed Extensions
Value Engineered

Every multi-plot assessment includes a free specification review. We tell you where the savings are before you commit to a build spec.

The design stage is where compliance decisions matter most.

Building regulation compliance is a design problem, not just a sign-off problem. The choices made during the design phase — insulation specification, glazing ratios, heating system, orientation — determine your energy performance, your compliance route, and ultimately your build cost.

Most assessors engage late, when the design is locked and your options are limited. We prefer to engage early, when a single change to an insulation spec or thermal bridging detail can save thousands per plot without touching the design intent or the EPC rating.

That's what our Value Engineered Compliance approach means in practice: compliance calculations that feed back into the design, not just certify it.

Planning stage
Energy Statements & early SAP
Predicted energy assessment for planning submission. Identifies any glazing or fabric constraints before design is fixed.
Technical design
SAP, U-values & PSI optimisation
Full SAP modelling, U-value calculations, and bespoke Psi values for junctions. This is where specification savings are found.
Pre-construction
Overheating & heat loss
Part O overheating assessment and heat loss modelling before procurement finalises the spec and HVAC sizing.
Building control
Design stage submission
Predicted Energy Assessment, Part G and Part O documentation submitted. As-built assessment coordinated with on-site testing at completion.

Nine design-stage compliance services.

Every assessment your development needs, from planning application through to Building Control sign-off — delivered by an accredited team with a single point of contact.

Part L
SBEM Calculations
Simplified Building Energy Model assessments for non-domestic and mixed-use commercial buildings demonstrating Part L compliance.
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Planning
Energy Statements
Planning application reports demonstrating compliance with local authority sustainability policies and energy efficiency targets.
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Part O
Overheating Assessments
Simplified and dynamic Approved Document O compliance modelling. Required for all new residential dwellings under Part O 2021.
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Part L / F
Heat Loss Calculations
Room-by-room dynamic thermal modelling using local weather data to inform HVAC design, heating system sizing, and ventilation specification.
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BS EN ISO
U-Value Calculations
Thermal transmittance calculations for walls, roofs, floors, and windows to BS EN ISO 6946. Essential for SAP input and Building Control submissions.
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BS EN ISO
PSI-Value Calculations
Bespoke linear thermal transmittance for junctions. Under Part L 2021 ACDs are gone — calculated Psi values are essential for compliance and cost optimisation.
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Part G
Water Usage Assessments
125 litre/person/day wholesome and non-wholesome water consumption calculations for planning and Building Control sign-off.
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Part L
Overglazed Extension Calculations
Part L compliance assessments for highly glazed extensions with over 25% glazing area, demonstrating acceptable thermal performance.
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As Built
On-Site Testing
Need air tightness, sound, ventilation, or smoke shaft testing? See our full As Built & Testing services.
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Which regulations do our design services cover?

Each Build Envelope design service maps directly to one or more Approved Documents — the technical guidance documents that set out how to comply with Building Regulations.

Approved Document
Part L — Energy
Conservation of fuel and power. The main energy performance requirement for new build and major renovations.
Approved Document
Part O — Overheating
Introduced in 2021. Requires all new residential dwellings to demonstrate acceptable overheating risk using simplified or dynamic methods.
Approved Document
Part G — Water
Water efficiency requirements for new dwellings. Maximum wholesome water consumption of 125 litres per person per day.
Approved Document
Part F — Ventilation
Ventilation requirements to maintain indoor air quality. Heat loss calculations support HVAC sizing and ventilation system selection under Part F.

Local accredited assessors for design stage compliance across the Midlands and South West.

We engage at design stage to ensure your project meets Part L, Part O, and local planning requirements — before procurement locks in your choices. Our assessors understand regional building control expectations.

Birmingham & West Midlands

Design stage compliance for residential and commercial developments across Birmingham, Solihull, Coventry, Wolverhampton, and the wider West Midlands. SAP, SBEM, overheating, energy statements, and U-value calculations.

Bristol & South West

Planning and building regulations compliance across Bristol, Bath, South Gloucestershire, and the surrounding South West. We navigate local authority sustainability policies alongside Part L and Part O requirements.

Worcestershire

Based in Worcester — design stage services across Malvern, Droitwich, Evesham, Bromsgrove, and Redditch. Our home county with the fastest turnaround and deepest local planning knowledge.

Gloucestershire

Design compliance for new homes, extensions, and commercial projects across Cheltenham, Gloucester, Stroud, Tewkesbury, and the Cotswolds. Early engagement to flag risks before they become costly.

Oxfordshire

Part L and Part O compliance for residential and commercial projects across Oxford, Banbury, Bicester, Witney, and the wider Oxfordshire area. Full design stage calculation services.

Wider England & Wales

As government-accredited assessors, our design stage calculations and reports are valid across the whole of England and Wales. We regularly work on projects outside our core regions.

Looking for design stage compliance near you? Whether you're planning a housing scheme in Birmingham, a commercial development in Bristol, or an extension in the Cotswolds — our accredited team delivers SAP, SBEM, overheating, and energy compliance from a single point of contact. Call 01386 365145 or email us to get started.

Free Specification Review

Have a development in mind?
Send us your drawings.

We'll review your specification at no cost and show you exactly where the savings are — before you commit to anything.

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Get in touch

Tell us about your project — development type, number of plots, and which services you need — and we'll come back with a quote and programme, usually within one working day.

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