Choosing an Architect for House Extensions: Electrician's Guide

When you're planning a house extension in the North East, your architect's understanding of electrical requirements—or lack thereof—will directly affect your final bill, your compliance status, and how quickly you can actually use the new space. A good architect involves the electrical contractor early and asks the right questions about load capacity, cable routes, and Building Regulations Part P. A poor one might design a beautiful kitchen extension with nowhere sensible to run new circuits, or ignore that your 60-amp consumer unit won't handle the extra demand.

This guide approaches architect selection from a qualified electrician's perspective. I've worked on too many extensions where the drawings looked good until we got on site and discovered the real constraints. Here's what you need to know.

Why Electricians Care About Architect Selection for Extensions

An architect's role isn't to design your electrics—that's our job—but it absolutely is to understand the constraints and involve us early enough to influence the layout.

The architecture and the electrical installation are physically intertwined. Cable routes need to be planned before walls go up. Your new kitchen might need a dedicated 32A circuit for an induction hob; that cable has to come from your consumer unit, and it needs a sensible path that doesn't run through structural zones or under future finishes. If the architect hasn't thought about this, you're paying for the building twice.

Part P of Building Regulations (electrical safety) requires that any significant rewiring or new circuits are installed by a competent person—either a qualified electrician or a Building Control–approved contractor. If the architect hasn't factored in that an extension might trigger rewiring requirements elsewhere in the house, the cost forecast is wrong from the start.

From our side, we work best when we can see the architect's plans early, flag potential issues, and collaborate. I've had architects refuse to shift a load-bearing wall by 30cm that would have made cable routing logical and saved the client £400. I've also had brilliant architects who called me at sketch stage and said, "Where do you want everything?" That's the difference between a smooth project and a frustrating one.

Essential Qualifications to Look for in UK Architects

Check that your architect is registered with the ARB (Architects Registration Board). This is not optional. ARB registration is a legal requirement to call yourself an architect in the UK. You can verify registration on the ARB website.

RIBA membership (Royal Institute of British Architects) is a professional endorsement—not a legal requirement, but a good indicator. RIBA members follow a code of conduct and professional standards. Most established practices in the North East are RIBA-chartered.

Look for:

• Minimum 5–10 years' experience with residential extensions similar in scope to yours.
• Building Regulations approval experience. The architect should have shepherded projects through local authority or approved inspector sign-off before.
• Evidence of working with building services contractors (electricians, plumbers, structural engineers). Ask for references and examples.
• Professional indemnity insurance. This is essential. If things go wrong, you need recourse.

Do not assume that an architect who's excellent at listed buildings or conservation work will understand the practical constraints of a modern domestic extension with smart heating, EV charger integration, or modern appliance loads.

Key Questions About Building Regulations and Compliance

Before you engage an architect, ask:

1. "Will this extension trigger Building Regulations approval?"

Extensions almost always do. New build or material change always needs sign-off. Make sure the architect understands the process and timescale (typically 4–8 weeks for approval, plus inspection points during work).

2. "Will you be handling Building Regulations submissions, or do I need a separate approved inspector?"

Good architects include this in their fee. Some expect you to appoint an approved inspector separately—make this explicit.

3. "How do you handle electrical compliance?"

Listen carefully. If they say "the electrician will sort it," that's vague. They should say something like: "I'll ensure the electrical layout is shown on plans; we'll agree cable routes with the electrician before work starts, and they'll certify the installation to Part P and provide an EICR test if existing circuits are touched."

4. "Will the extension require a new earthing system or changes to the main installation?"

If you're adding a significant load (say, underfloor heating and air source heat pump), your consumer unit might need upgrading, or even a new main switch. An architect who's thought about this will have flagged it.

Electrical Planning Questions to Ask Your Architect

Once you've appointed an architect, ask these before detailed design starts:

1. "Where is the consumer unit? Is there room to expand it or install a sub-board nearby?"

This is fundamental. If your consumer unit is in the garage and the extension is at the far end of the house, longer cable runs mean greater voltage drop, thicker cables, and higher cost.

2. "Have you planned for the electrical contractor to be involved at design stage?"

A good architect will include us in pre-design conversations, or at least early RIBA Stage 2 (Concept Design).

3. "Are there any planned appliances that will affect load calculations?"

Air source heat pumps, underfloor heating, EV chargers, electric cookers, and heat pumps all draw significant power. If the architect knows about these, we can calculate whether your existing consumer unit capacity (typically 60–100A) is sufficient or needs upgrading. Upgrading can cost £1,500–£3,500 depending on the DNO (Distribution Network Operator) and whether your supply cable needs replacing.

4. "What's the strategy for cable routes—walls, floors, under tiling?"

Cables under tiled floors or new concrete need to be in conduit and marked on plans. Walls might allow in-wall routing or surface-mounted trunking. The architect should show intent on plans.

5. "If this is a significant extension, will you specify an EV charger location or smart meter access?"

Modern houses are moving this way. Better to plan it now than retrofit.

Understanding the Design Process and Timeline

RIBA stages run from initial brief through to project completion. For an extension:

• Stage 1 (Preparation): Brief setting. 1–2 weeks typically.
• Stage 2 (Concept Design): Options developed. This is when electrical constraints should be identified. 3–6 weeks.
• Stage 3 (Spatial Design): Detailed layout. Cable routes finalised. 4–8 weeks.
• Stage 4 (Technical Design): Full specifications and Building Regulations submission. 4–8 weeks.

Total from start to Building Regulations approval: typically 3–5 months. If an architect says they can do it in 6 weeks, they're either very fast, or cutting corners.

Ask upfront: "What's your stage breakdown and timescale?" and "When do you involve the electrician?" A good answer is: "Electrician is consulted at Stage 2, confirmed at Stage 3, and specifications finalised at Stage 4."

Cost, Contracts and Insurance: What to Clarify

Architect fees for extensions typically range from 8–15% of build cost, though this varies. A £50,000 extension might cost £4,000–£7,500 in fees; a £150,000 one, £12,000–£22,500. Get a written fee proposal that specifies:

• What's included? (Planning, Building Regulations, design, site inspections, contractor liaison?)
• What's excluded? (Structural engineer, specialist reports, approved inspector?)
• Stage-by-stage breakdown. Can you pay on completion of each RIBA stage?
• Who pays for amendments after approval? (If you ask for the extension 1 metre wider after Building Regulations approval, there's a cost.)

Check their Professional Indemnity Insurance limit. £1–2 million is standard for residential work; it should cover your project value.

Ask about their Limitations of Liability clause in the contract. You want clarity on what they're responsible for if things go wrong.

Red Flags: Warning Signs When Choosing an Architect

Don't hire an architect if:

• They won't provide ARB registration number or it's expired.
• They're evasive about Building Regulations timescale or process. This suggests inexperience.
• They say "we don't worry about electrical—the sparks will figure it out." Lazy. Electrical planning should start in design.
• They can't name an approved inspector or Building Control contact. They should have a regular relationship.
• No professional indemnity insurance, or they won't provide evidence.
• References are all non-residential or in a different region. You want local experience with similar projects.
• They promise a fixed price for a service that depends on unknowns (like whether structural work is needed). Red flag for either cutting corners or an unforeseen bill later.
• They dismiss your questions about electrics or timescale as "not my concern." You want a collaborator, not a prima donna.

How Architects Work With Electrical Contractors

The best process runs like this:

1. Architect shares preliminary plans with electrician (often at RIBA Stage 2 or early Stage 3).

2. Electrician reviews: consumer unit location, cable routes, load assumptions, any challenges.

3. Electrician and architect discuss and agree on cable routes, sub-board location (if needed), and any changes to the building layout to facilitate electrics.

4. Architect updates plans to show agreed electrical routing.

5. At Stage 4 (Technical Design), electrician provides a schedule of work and loading information.

6. All parties agree on the approach before Building Regulations submission.

7. During construction, electrician and architect liaise on any on-site changes.

This minimises surprises and cost overruns.

A poor process has the electrician arriving on site with plans for the first time, then discovering the consumer unit is inaccessible or cable routes are blocked.

Portfolio Review: What to Look For

When reviewing an architect's portfolio:

• Look for residential extensions similar in scope to yours. A spectacular commercial refurb doesn't prove they can deliver a good kitchen extension.
• Ask how long the projects took and what the final cost was relative to budget. Significant overruns might indicate poor planning.
• Contact previous clients directly (the architect should provide references). Ask: Did the architect involve other trades early? Were there cost surprises? How was Building Regulations approval handled?
• Check that electrical layouts are shown on plans. This tells you they're thinking about it.
• Review the Building Regulations approval and Completion Certificate. Did the project receive sign-off without issues? Any snags?

FAQ: Common Questions About Hiring Architects for Extensions

Q: Do I legally need an architect for a small extension?

A: No. Planning Permission and Building Regulations approval can be done by anyone (or an approved inspector), but you need some design process. For extensions under 30 square metres with simple layouts, a surveyor or experienced builder might suffice. For anything more complex, an architect's input usually saves money in the long run by avoiding costly on-site mistakes.

Q: What's the difference between an architect and a surveyor for extensions?

A: An architect is trained in design, spatial planning, Building Regulations compliance, and project management. A surveyor typically specialises in measurement, condition surveys, or site management. Both can provide extension design, but architects usually have broader design experience. For your purposes, hire whoever has the most relevant extension experience and proper indemnity insurance.

Q: Should I get a detailed electrical estimate before appointing an architect?

A: Yes. Before detailed design, brief an electrician and get a rough estimate (often free or £100–200 for a detailed review). This informs the architect's budget and lets them adjust the layout accordingly. Once detailed plans exist, get a full quotation. This two-stage approach prevents nasty surprises.

Q: How much should an architect's fee be as a percentage of build cost?

A: 8–15% is the standard range. Smaller projects (under £50k) might be 12–15%; larger ones 8–12%. Some architects charge hourly (typically £150–300/hour depending on experience and location). Clarify which model is being used and what's included.

Q: Can an architect help with Planning Permission?

A: Yes, absolutely. Most architects include Planning Permission submission and liaison as part of their service. Some extensions don't need permission (single-storey, within allowed depth and height limits), but an architect will advise. Their fee should cover this; don't assume permission is automatic.

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Getting It Right

Choosing an architect is a significant decision. You're entrusting them with your brief, your budget, and your compliance. A good architect saves money by involving the right people early, asks the hard questions about electrics and building services, and gets you through Planning and Building Regulations efficiently.

From our experience at Energy North Ltd, the projects that run smoothest—and often end up cheaper—are those where the architect has engaged an electrician at design stage, shown cable routes on plans, and thought about load capacity and earthing from the start.

If you're in the North East and planning an extension, we're happy to discuss electrical planning with your architect early, or to review plans for feasibility. Get in touch at [https://energynorth.uk](https://energynorth.uk) for a no-charge initial conversation about what your extension's electrical needs might look like.