Planning permission and Building Regulations approval are separate. Planning considers whether development is acceptable in planning terms; Building Regulations set minimum standards for matters such as structure, fire safety, ventilation, energy performance, drainage and accessibility. An extension can be permitted development for planning purposes and still require Building Regulations approval.
For homeowners in Middlesbrough, Teesside and the wider North East, a coordinated technical package is the bridge between an approved concept and buildable information. Hepburn Architects’ Building Regulations service develops that information with the relevant consultants and project team.
Why most house extensions require Building Regulations approval
The construction of a new extension is generally controlled building work. The regulations apply even where no planning application was needed, because the two regimes address different risks. There are limited exemptions for particular small detached buildings, conservatories and porches that meet specified conditions, but an exemption should be checked rather than assumed—especially when openings are altered, heating is extended or the work affects structure.
The official GOV.UK Building Regulations approval overview explains the separate need for planning and Building Regulations approvals and the choice of building-control body for applicable work.
Full Plans and Building Notices
Under the local-authority route, a Full Plans application provides drawings, specifications and, where necessary, calculations for assessment before or during the early construction period. It gives the design team and builder a reviewed set of information and a formal decision on the plans, subject to the application process and any conditions.
A Building Notice is a simpler notification route available for some projects. Detailed plans are not approved in advance, and the work is assessed through site inspections. That can suit limited, straightforward work, but it places greater weight on information being resolved during construction and is not available in every circumstance.
For a designed extension involving structure, fabric junctions, drainage and several trades, coordinated Full Plans information is generally the more robust route. The government’s guidance on how to apply describes Full Plans as the most thorough application method. The appropriate route should nevertheless be chosen for the actual project and building-control provider.
What a proper technical drawing package normally includes
Plans, elevations and sections
Proposed drawings establish dimensions, levels, room arrangements, openings and the relationship between new and existing construction. Sections are particularly important: they explain floor, wall and roof junctions that a plan alone cannot show.
Foundations and ground-floor construction
The package should set out the intended foundation and floor strategy, damp protection, insulation and relevant interfaces. Final foundation requirements may depend on site investigation, nearby trees, drains, made ground or the building-control body’s observations; drawings should not pretend unknown conditions are known.
External walls and roof build-ups
Technical details identify materials, structural support, cavities, membranes, ventilation paths, weathering and junctions with the existing building. Roof falls, upstands, abutments and rainwater disposal need to work as a system rather than as isolated notes.
Insulation and thermal continuity
The design should state insulation types and thicknesses, relevant thermal values and continuity at floors, walls, roofs, openings and structural penetrations. Junction design helps limit unwanted heat loss and condensation risk. Where existing thermal elements are renovated or retained openings change, those implications also need assessment.
Ventilation
Background ventilation, purge ventilation and extract ventilation must be considered together. A larger open-plan kitchen can change the ventilation strategy for the existing house, and removing an external wall can alter how adjoining rooms receive fresh air.
Fire safety and means of escape
Drawings should address relevant escape windows, protected routes, smoke and heat alarms, internal linings and fire resistance. Open-plan layouts, loft accommodation, attached garages and structural steelwork can require project-specific fire-safety consideration.
Structural openings, beams and load paths
Removing a rear wall usually needs more than a beam size. The engineer and architect must coordinate bearings, columns where needed, lateral stability, padstones, existing construction and how loads reach suitable support. The drawings should reserve realistic zones for the structure before ceiling heights and glazing are fixed.
Drainage
The package normally identifies foul and surface-water routes, gradients, access points and connections so far as they are known. Building over or close to a public sewer can require separate agreement with the sewerage undertaker. Rainwater disposal should be coordinated with site constraints and applicable drainage requirements.
Glazing, stairs and guarding
Window and door information may need to address thermal performance, ventilation, safety glazing, guarding and means of escape. Where stairs, steps, balconies or level changes are involved, rise, going, headroom, handrails and guarding must be developed accurately.
Electrical safety, moisture and weather protection
Technical information should recognise controlled electrical work, safe service coordination and certification responsibilities. Damp-proof courses, trays, membranes, flashings and thresholds must form continuous protection suited to the proposed construction and exposure.
When structural-engineer calculations are required
Calculations and structural details are commonly required for beams, lintels, columns, foundations, roof members, stability frames and alterations that redirect loads. The engineer’s scope depends on the design and the existing building. Their information should be incorporated into the architectural set, not issued as an unrelated appendix that conflicts with dimensions or levels.
This coordination is particularly important for ambitious openings and reconfigured ground floors within a house-extension project. Early structural input can protect the architectural intent while exposing cost or buildability issues before work starts.
Coordination with Building Control, the builder and consultants
Building Control checks compliance and inspects at relevant stages; it does not act as the designer, clerk of works or contractor. The architect coordinates design information, the structural engineer is responsible for their calculations, specialist designers provide their packages, and the builder remains responsible for constructing safely and in accordance with the approved information and statutory requirements.
Queries should be recorded and resolved consistently across drawings and specifications. A change to a beam can affect insulation, ceiling levels, glazing and fire protection. A drainage discovery can affect foundations and floor levels. Good coordination treats these as connected design decisions.
Why planning drawings are not construction drawings
Planning drawings communicate scale, appearance, use and relationships sufficiently for a planning decision. They rarely define every construction build-up, junction, structural member, service route or compliance note. Starting on site from that limited set transfers unresolved design work to the builder at the most expensive moment. Our Journal article Why a planning approval does not mean your extension is ready to build explains this distinction in more detail.
When can work start?
The answer depends on the application route, notices, appointment of the building-control body and other statutory duties. A Building Notice can allow work to begin after the prescribed notice period, but it does not provide advance approval of detailed plans. Under Full Plans, commencing before issues are resolved can expose the client to redesign and remedial risk.
Before commencement, the client should understand the Building Regulations process, dutyholder responsibilities, required notifications, planning conditions, party-wall position, any sewer agreement and the contract with the builder. “Allowed to start” is not the same as “ready to start.” The current official procedure should be confirmed with the chosen building-control body.
Site-specific North East considerations
A North East postcode does not justify assumptions about geology, mining legacy or ground conditions. The correct response is evidence: planning and property records, utility and drainage searches, a measured survey, arboricultural advice where trees matter, and proportionate ground or structural investigation when indicated. A project in Middlesbrough should be assessed on its site, existing construction and proposed loads—not a regional generalisation.
Exposure, levels, existing solid walls, ageing drainage, access constraints and the sequence of occupied-house work may also shape details. These are design inputs to verify, not claims that every North East home shares the same condition.
Common problems caused by incomplete technical information
- Tender prices contain broad allowances, making quotations difficult to compare.
- Structural zones clash with glazing, ceilings, ducts or existing services.
- Insulation and damp-control continuity is improvised at junctions.
- Drainage routes or sewer constraints are discovered after excavation.
- The builder seeks repeated decisions on site without enough time to assess consequences.
- Changes are recorded inconsistently, leaving the construction and approval sets out of step.
Drawings cannot eliminate every discovery in an existing building, but they should reduce foreseeable uncertainty and provide a clear basis for pricing, coordination and inspection.
A practical pre-construction checklist
- Confirm the planning position and discharge any pre-commencement planning conditions.
- Choose and appoint the building-control body; agree the application route and inspection process.
- Complete coordinated architectural and structural information, with specialist designs identified.
- Check drainage, utilities, trees, boundaries and access using evidence appropriate to the site.
- Understand client, designer and contractor duties under the Building Regulations and health-and-safety legislation.
- Issue the same current information to the builder, consultants and Building Control.
- Agree the building contract, scope, price basis, programme, change procedure and insurance position.
Homeowners can review Hepburn’s completed residential work and use the indicative fee calculator when planning the next stage.
Frequently asked questions
Do I need Building Regulations approval if planning permission is not needed?
Usually for an extension, yes. Permitted-development status concerns planning only. Check any claimed exemption against the actual work.
Can my builder prepare the technical details?
Some contractors offer design responsibility, but the scope, competence, coordination and contractual responsibility must be explicit. A builder’s price based only on planning drawings is not a substitute for resolved information.
Are structural calculations part of Building Regulations drawings?
They are often a related structural engineer’s package rather than architectural calculations. They must nevertheless coordinate with the architectural drawings submitted and used for construction.
Does Building Control approval guarantee workmanship?
No. Building Control assesses compliance through the approval and inspection process; it does not continuously supervise the work or replace the contractor’s and dutyholders’ responsibilities.
Can drawings change after approval?
Changes can occur, but material revisions should be coordinated, notified and approved through the appropriate process before affected work proceeds. Unrecorded site changes create compliance and handover risks.
Plan the technical stage before construction
If you are preparing a North East house extension for construction, contact Hepburn Architects to discuss a coordinated Building Regulations package. We can define the architectural scope, identify the consultant information needed and help establish a clearer route from design to site.
Continue with the relevant service and guide.
Planning a residential project?
Speak directly with Hepburn Architects about the site, design and likely next step.