How much does an architect cost ?
A Guide To Architect Fees In Cheshire 2026
The construction cost of a very basic house extension starts from £2,500 per square metre and significant internal works from around £1000 per square meter inc vat (at 20%), plus the cost of any new kitchens or bathrooms, plus vat. This budget would allow for a basic standard of finish and will not include luxury items, such as under-floor heating, timber windows, granite worktops or wooden flooring.
To achieve a luxury finish, a minimum budget of £3,500 per square meter for extensions and £2000 per square meter for significant internal works including vat, or more per square metre is necessary.
This section has been designed as a guide to those wishing to undertake residential house extensions on their own project or build themselves a new home. It has been based on several similar projects of ours completed recently as of the mid-2026. Every project has its own issues and the scope of service we offer, the consultant’s needs, and construction costs will also vary greatly from project to project.
*as per mid 2026 prices
PROJECT TYPE ONE
Project description: Single storey rear extension 6.5m x 4m and associated alterations to form an open plan kitchen living space, with strong links to the garden and lots of natural daylight. We have assumed 25m² of internal works to the existing dwelling in the costs below in addition to the extension. The extension required planning permission, but the site is not listed or in a conservation area.
How much will it cost to design?
An estimate of fees likely to be charged by others and the local authority are:
Structural Engineer’s Fees
£800 - £2,000 + VAT including site investigation
Heat Loss Calculations Fee
£350 - £550 + VAT
OS Map
£30 - £40
Ordnance Survey Copyright License Fee for 12 months
Local Authority Householder Planning
Application Fee £548 including The Planning Portal submission Fee of £91.
Approved Inspectors Building Regulation Plan Check and Site Inspection Fees
£1200 - £1600
Architects’ Fees
Design Stage
Survey
£1,500
Measuring the existing building or site.
Concept Design
£1,600
Drawing up simple plans elevations and working with the client to establish the basic design. Establishing the budget and timescale for the project.
Planning Application
£1,200
Preparing and lodging a planning application. Negotiating with planning officers. Addressing objections by neighbours.
Building Regulations, Specification etc. (Technical Design)
£3,920
Preparing and lodging a building regulations application. Working with a structural engineer. Working with an energy consultant. Preparing detailed, technical drawings of the project. Addressing queries by the local Building control department or approved inspectors.
Pre-Construction (Tender)
£552
Establishing suitable contractors for the project, Issuing tender packages to building contractors. Reviewing tender returns and negotiating the final construction price.
Design Stage Principal Designer under the CDM Regulations and Building Regulation
£552
Construction Stage Construction Contract
£7,000
Preparing a detailed construction contract between property owner and builder. Inspecting building work once per week. Writing regular reports to all parties. Issuing a valuation and payment certificate once per month. Controlling variations in costs and timescales during construction.
Construction Stage Principal Designer under the CDM Regulations and Building Regulation
£552
Post-Construction (Snagging)
£950
Inspecting the finished building and agreeing a list of defects, or ‘snagging’. Negotiating with building control department to ensure completion certificate is issued. Controlling the release of retention funds to the contractor once a snagging item have been addressed.
PROJECT TYPE TWO
Project description: Rear 4m x 9m two storey rear extension to existing dwelling and 3m x 6, first floor side extension, extensive internal alterations including – new kitchen, bathrooms, alterations to room layouts.
How much will it cost to design?
An estimate of fees likely to be charged by others and the local authority are:
Structural Engineer’s Fees
£1,200 - £3,500 + VAT including site investigation
Heat Loss Calculations Fee
£350 - £550 + VAT
Tree Survey and Arboriculturally Report
£700 - £1,000 + VAT
OS Map
£30 - £40
Ordnance Survey Copyright License Fee for 12 months
Topographical Survey Fee
£1,000
Local Authority Householder Planning Application Fee
Application Fee £548 including The Planning Portal submission Fee of £91.
Approved Inspectors Building Regulation Plan Check and Site Inspection Fees
£1,200 - £1,600
Architects' Fees:
Design Stage
Survey
£2,940
Measuring the existing building or site.
Concept Design
£3,185
Drawing up simple plans elevations and working with the client to establish the basic design. Establishing the budget and timescale for the project.
Planning Application
£2,000
Preparing and lodging a planning application. Negotiating with planning officers. Addressing objections by neighbours.
Building Regulations, Specification etc. (Technical Design)
£6,800
Preparing and lodging a building regulations application. Working with a structural engineer. Working with an energy consultant. Preparing detailed, technical drawings of the project. Addressing queries by the local Building control department or approved inspectors.
Pre-Construction (Tender)
£1,000
Establishing suitable contractors for the project, issuing tender packages to building contractors. Reviewing tender returns and negotiating the final construction price.
Design Stage Principal Designer under the CDM Regulations and Building Regulation
£750
Construction Stage
Construction Contract
£14,400
Preparing a detailed construction contract between property owner and builder. Inspecting building work once per week. Writing regular reports to all parties. Issuing a valuation and payment certificate once per month. Controlling variations in costs and timescales during construction.
Construction Stage Principal Designer under the CDM Regulations and Building Regulation
£1,100
Post-Construction (Snagging)
£1,200
Inspecting the finished building and agreeing a list of defects, or ‘snagging’. Negotiating with building control department to ensure completion certificate is issued. Controlling the release of retention funds to the contractor once a snagging items have been addressed.
PROJECT TYPE THREE
Project description: A new large two storey detached 4-bedroom house in urban setting.
How much will it cost to design?
Structural Engineer’s Fees
£2,000 - £4,000 + VAT including site investigation
SAP Calculations Fee
£300 - £500 + VAT
Air Pressure Test Fee
£350 + VAT per visit
Water Calculations
£250 + VAT
OS Map
£30 - £40
Ordnance Survey Copyright License Fee for 12 months
Topographical Survey Fee
£1,200
Local Authority Householder Planning Application Fee
£610 plus the Planning Portal Submission Fee of £91.
Approved Inspectors Building Regulation Plan Check and Site Inspection Fees
£1,500 - £2,000
Building Warranty
£5,000
Architects' Fees
Design Stage
Concept Design
£4,000
Drawing up simple plans elevations and working with the client to establish the basic design. Establishing the budget and timescale for the project.
Planning Application
£3,750
Preparing and lodging a planning application. Negotiating with planning officers. Addressing objections by neighbours.
Building Regulations, Specification etc. (Technical Design)
£9,500
Preparing and lodging a building regulations application. Working with a structural engineer. Working with an energy consultant. Preparing detailed, technical drawings of the project. Addressing queries by the local Building control department or approved inspectors.
Pre-Construction (Tender)
£1,000
Establishing suitable contractors for the project, issuing tender packages to building contractors. Reviewing tender returns and negotiating the final construction price.
Design Stage Principal Designer under the CDM Regulations and Building Regulation
£1,000
Construction Stage
Construction Contract
£16,000
Preparing a detailed construction contract between property owner and builder. Inspecting building work once per week. Writing regular reports to all parties. Issuing a valuation and payment certificate once per month. Controlling variations in costs and timescales during construction.
Construction Stage Principal Designer under the CDM Regulations and Building Regulation
£1,500
Post-Construction (Snagging)
£1,200
Inspecting the finished building and agreeing a list of defects, or ‘snagging’. Negotiating with building control department to ensure completion certificate is issued. Controlling the release of retention funds to the contractor once a snagging item have been addressed.