Extend your Withernsea with an extension

A flat roof extension is a great way to add extra space to your home without splashing out on the costs of a pitched roof extension. Often exempt from planning permission rules, you can build a flat roof extension up to 3 metres in height as long as it's not visible from a road. But how much do they cost in Withernsea?

Build a flat roof extension cost in Withernsea - Sort by rates or availability

S.E.S Services

From £21,616

(last active 04/09/26)

Location

Ings, HU8

Need an Extension Builder in Withernsea? S.E.S Services has been helping local clients (20 mile radius) with their extension buildering jobs for ma...

Absolute Finishes

From £21,696

(last active 04/09/26)

Location

Ings, HU8

Absolute Finishes is an established extension buildering business in Withernsea. We come highly recommended and provide competitive quotes for your...

ACG Building Services

From £21,880

(last active 04/09/26)

Location

Wawne, HU7

ACG Building Services is an established extension buildering business in Withernsea. We come highly recommended and provide competitive quotes for ...

City Builders

From £21,608

(last active 04/09/26)

Location

The Avenues, HU5

Experienced extension builder ready to quote for your work. City Builders is the best extension builder in Withernsea. No obligation free quotes an...

Ashley Cook Builders

From £21,800

(last active 04/09/26)

Location

Wawne, HU7

Need to find an Extension Builder near you for all your extension buildering work?

Ashley Cook Builders provides a local, trusted extension...

J LLOYD CONSTRUCTION LTD

From £22,072

(last active 02/09/26)

Location

Wawne, HU7

J LLOYD CONSTRUCTION LTD are here to help customers who need an Extension Builder in Withernsea. We offer a competitive rate to complete all your e...

HEPWORTH BUILDING

From £21,704

(last active 02/09/26)

Location

Cottingham, HU16

Need to find an Extension Builder near you for all your extension buildering work?

HEPWORTH BUILDING provides a local, trusted extension bu...

RB Building Services

From £21,608

(last active 10/08/26)

Location

Spring Bank, HU3

RB Building Services is an established extension buildering business in Withernsea. We come highly recommended and provide competitive quotes for y...

A F Beckett

From £21,776

(last active 16/06/26)

Location

Grimsby, DN32

Need an Extension Builder in Withernsea? A F Beckett has been helping local clients (20 mile radius) with their extension buildering jobs for many ...

THOMPSON BUILDERS

From £21,776

(last active 07/06/26)

Location

Hornsea, HU18

Need to find an Extension Builder near you for all your extension buildering work?

THOMPSON BUILDERS provides a local, trusted extension bu...

Flat roof extension cost in Withernsea

Estimates for build a flat roof extension near Withernsea

A flat roof extension ranges from the cheapest of £21,608 (City Builders based in HU5) to the dearest of £22,072 (J LLOYD CONSTRUCTION LTD based in HU7), but these are just estimates. While they give you an idea of who will be better value, the best way to compare costs is to get real quotes. 

Find out how much your flat roof extension will cost in Withernsea by posting a job with HaMuch. We'll send it to extension builders in Withernsea.


Get extension builder rates instantly

Get extension builder rates instantly (excluding VAT or callout charges)
Location in UKHourly RateDaily Rate
Build A Flat Roof Extension near Grimsby£32£246
Build A Flat Roof Extension near North East Lincolnshire£32£246
Build A Flat Roof Extension near Cleethorpes£32£246
Build A Flat Roof Extension near Hull£29£223
Build A Flat Roof Extension near Willerby£29£221
Build A Flat Roof Extension near Beverley£29£223
Build A Flat Roof Extension near East Riding£29£223
Build A Flat Roof Extension near North Lincolnshire£28£216
Build A Flat Roof Extension near Bridlington£32£252
Build A Flat Roof Extension near East Lindsey£27£198

Estimates for common extension builder jobs in Withernsea;

Whether you’re looking to extend your kitchen with a side return extension or you want to convert your basement into a liveable space, read our cost guides to get an idea of how much each project costs before getting a more accurate quote from our database of reliable tradespeople.

Underpin a building

Underpin a building - £17,254

Two storey extension

Two storey extension - £87,630

Build a timber frame extension

Build a timber frame extension - £25,754

Build a swimming pool

Build a swimming pool - £80,754

Single storey extension

Single storey extension - £50,072

Side return extension

Side return extension - £38,728

Install an RSJ

Install an RSJ - £1,954

Outbuilding

Outbuilding - £9,754

Build a Mansard loft conversion

Build a Mansard loft conversion - £51,754

Loft conversion

Loft conversion - £31,440

Build a kitchen extension

Build a kitchen extension - £41,754

Hip to gable loft conversion

Hip to gable loft conversion - £41,754

Granny annexe

Granny annexe - £86,754

Garden office

Garden office - £9,754

Convert a Garage

Convert a Garage - £15,754

Garage

Garage - £18,254

Build a flat roof extension

Build a flat roof extension - £21,754

Build a dormer loft conversion

Build a dormer loft conversion - £41,754

Concrete foundations

Concrete foundations - £6,004

Convert a bungalow loft

Convert a bungalow loft - £28,754

Convert a basement

Convert a basement - £34,728

More extensions & conversions cost guides...