House Extension Cost

Guide Prices Only – fill out the form on the contact us page or click on the live support button on the bar at the bottom of the page for our latest offers and prices.

Loft conversion prices based on the following general details please contact for a specific quote:

Loft Conversions Planning Permission Building Regulations Planning & Building Regs
Bungalow upto 4 Bed £440 £410 £770
Bungalow 5 Bed+ £550 £445 £850
House upto 3 bed £450 £415 £785
House 4 bed+ £470 £415 £800
Structural Calcs POA*
Single storey extension design prices based on the following general details please contact for a specific quote:
Single Rear or Side Extension Planning Permission Building Regulations Planning & Building Regs
Bungalow upto 4 Bed £370 £380 £675
Bungalow 5 Bed+ £410 £395 £715
House upto 3 bed £400 £380 £710
House 4 bed+ £420 £380 £725
Structural Calcs POA*
2 storey extension design prices based on the following general details please contact for a specific quote:
2 Storey Rear or Side Extension Planning Permission Building Regulations Planning & Building Regs
Bungalow upto 4 Bed n/a n/a n/a
Bungalow 5 Bed+ n/a n/a n/a
House upto 3 bed £450 £460 £810
House 4 bed+ £465 £460 £820
Structural Calcs POA*
Two storey side or rear extension with a Single storey side or rear extension design prices based on the following general details please contact for a specific quote:
2 Storey Rear or Side Extension with Single Storey Extension Planning Permission Building Regulations Planning & Building Regs
Bungalow upto 4 Bed n/a n/a n/a
Bungalow 5 Bed+ n/a n/a n/a
House upto 3 bed £465 £460 £830
House 4 bed+ £485 £460 £850
Structural Calcs POA*

We offer other services alongside our planning and building regulations such as measured property surveys, structural design and calculations, tender packages and topographical surveys and site engineering setting out services. Please Contact us with your requirements.

Please note
– POA* – Price On Application


Typical Scope of Work And Fees For Private Residential Projects (house extensions, loft conversions, other alterations / conversions to existing houses)

Stage 1 – Feasibility Studies and Application for Planning Permission
–        initial site visit, analysis of client’s brief and identification of possible constraints on development
–        fee proposal and schedule of design work
–        measured site survey in order to draw accurate existing plans, sections and elevations
–        conceptual studies and production of proposed layout
–        amendments to proposal if requested by client
–        production of final design approved by client
–        pre-application consultation with planning authority if required
–        submission and monitoring of planning application
–        issue of approved planning documents to client

Fee Example for Stage 1
–        Single storey, ground floor garden extension for terraced house – from £400
–        Two storey extension for 3/4 bedroom detached house – from £450

Stage 2 – Building Regulation application
–        production of detailed drawings required by Building Regulations Approved Documents
–        design coordination with structural engineer and other consultants if required
–        submission of Full Plans application to Building Control

Fee Example for Stage 2
–        Single storey, ground floor garden extension for terraced house – from £380
–        Two storey extension for 3/4 detached house – from £460

Please note
– Fees do not include statutory charges for Planning and Building Regulation applications, pre-planning consultations if charged by Local Authorities, and other consultants’ fees, if they have to be involved in design process.
– If your extension requires any further local authority reports, such as a flood risk assessment, tree survey, structural calculations etc; then these are charged separately to our design fees.


Below are a few examples of house extensions together with the approximate cost a builder could charge. Much will depend on your desired specification but we hope this provides a useful starting point for budgeting.


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single storey extension – cost

£1500 – £3200 per Sq M approx.

The range represents the difference in finish from a standard to high end.


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double storey extension – cost

£1400 – £3000 per Sq M approx.Double storey extension to incorporate bedroom on first floor and additional living space on ground with high quality sliding door

If you need any help, assistance or quotes call us on 07923 104 425, email: info@remars-builders.com