Ashbridge Design

Design It Properly. Inspect It Properly.

Engineer-led Extension Design and New-build Inspections

Extension drawings, planning support, structural calculations and independent new-build inspections, all led by a civil engineer. Based in Shirley, Solihull, covering all of England.

Plan an ExtensionRequest a Snagging Inspection
Engineer-led · MSc Civil Engineering15 Years' ExperienceFixed PricesSnag Reports in 24 Hours
Technical drawing of a house with a new single-storey extension highlighted in amber 6000 3000 PROPOSED EXTENSION SIDE ELEVATION · EXISTING + PROPOSED · 1:100

Extending or Converting?

Extension Design, From Planning to Build

Planning drawings, Building Regulations drawings and structural calculations from one engineer. Single and double-storey extensions, lofts and garage conversions.

Planning Drawings From £650

See Design PricesCan I Extend?
MSc
CIVIL ENG15 YEARS

Why Engineer-led Matters

Many Drawing Firms Use Drafters, and Many Snagging Firms Use Ex-tradespeople. Ashbridge Is Run by a Civil Engineer.

  • Drawings designed with building control in mind: beams, foundations and drainage are considered from day one, not bolted on later.
  • Structural calculations in-house: no third-party engineer, no extra 1–3 week wait, no extra invoice.
  • Inspections to an engineer's standard: we check against Building Regulations and warranty tolerances, not just a decorator's checklist.

How It Works

Two Services, One Standard

Extension Design

  1. Free Scope Review

    Send photos and your idea. You get a fixed price, usually the same day.

  2. Measured Survey

    We measure the house and check your planning history and council rules.

  3. Design & Drawings

    Options, then planning drawings. We submit and manage the application.

  4. Building Regulations & Calculations

    Technical drawings and in-house structural calculations, ready for your builder.

New-build Inspection

  1. Instant Price

    Priced by bedrooms. Request your inspection online and we'll confirm the date.

  2. Inspection

    A room-by-room inspection, plus the loft and outside, against Building Regulations and warranty standards.

  3. Report in 24 Hours

    Photographed, located, graded and ready to send to the developer.

  4. Re-inspection

    Optional: we come back and check the developer's fixes.

Buying From an NHQB-registered Developer?

You Can Request an Independent Pre-completion Inspection

Under the New Homes Quality Code, registered developers must let your inspector in before completion. The inspection takes place after your Notice to Complete is served and before completion, and the notice period is normally at least 14 calendar days. Defects that breach warranty standards should be put right before completion, or within 30 days.

Check My Inspection Window
Illustration of a wall being inspected with snags marked 0102

Clear, Fixed Prices

What It Costs

Fixed prices, no hidden extras. Council fees are paid separately.

Planning Drawings

From £650

Planning Drawings

Planning + Building Regulations

From £1,350

Design Prices

Structural Calculations

From £295

Structural Calculations

Snagging Survey

From £325

Snagging Prices

Areas We Cover

Based in Solihull, Covering Birmingham and All of England

Around Birmingham, the West Midlands and nearby towns, our lead engineer inspects and surveys in person. Across the rest of England, qualified inspectors who belong to a recognised professional body for surveying, and our survey partners, work to the same checklist, and every report and drawing set is signed off by the lead engineer.

See All AreasBirmingham

Common Questions

How Much Do Extension Drawings Cost?
Planning drawings for a single-storey extension start at £650. Planning and Building Regulations together start at £1,350, and the Complete package with structural calculations starts at £1,695.
Do You Visit the Property?
Yes. Every project starts with a measured survey. Around Birmingham and the West Midlands our engineer visits in person. Elsewhere in England, the survey is carried out by a partner surveyor or by 3D scan, depending on the project.
When Do Thermal Imaging or Drone Checks Add Value?
Thermal imaging can point to likely insulation gaps, draughts or hidden leaks, but works best when inside and outside temperatures differ clearly, and findings usually need checking another way. A drone can help where a roof is hard to see from the ground. Both are most useful when you have a specific concern, such as cold spots, unexplained damp or a suspected roof problem. We do not currently offer them, so ask a specialist if you need one.
What Is a Snagging Survey?
An independent inspection of a new-build home that finds defects: anything unfinished, damaged or not built to standard. You get a report the developer has to respond to.

Ready for a Fixed Price?

Tell us about your project or the home you're buying. You'll get a clear, fixed quote, usually the same day.

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