Extend your Penarth 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 Penarth? To see prices and availability for your job click green button.

HaMuch is Excellent

How HaMuch saves you money

Post your job for free

Post your job for free

We send your job to ALL Penarth extension builders

Compare quotes

Compare quotes

Available extension builders in Penarth reply

Save Money

Save Money

Select your affordable Penarth extension builder

Post your job

From £22,240

Get quotes

L.Jones Building

Lewis Jones

Member since October 2026

We are polite, punctual and respectful small construction business. We take pride in all our work.

From £21,728

Last active Oct 26
Get quotes

The Philog Paving Services

The Philog Paving Services is an established extension buildering business in Penarth. We come highly recommended and provide competitive quotes fo...

From £21,808

Last active Oct 26
Get quotes

Chapman Builders

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

From £21,616

Last active Sep 26
Get quotes

JA Building Maintenance

Experienced extension builder ready to quote for your work. JA Building Maintenance is the best extension builder in Penarth. No obligation free qu...

From £21,784

Last active Sep 26
Get quotes

TOR BUILD

Experienced extension builder ready to quote for your work. TOR BUILD is the best extension builder in Penarth. No obligation free quotes and many ...

From £21,632

Last active Sep 26
Get quotes

Charles Marshall Contracting Ltd

Relax... you have found a reliable extension builder in Penarth. Charles Marshall Contracting Ltd is a friendly and reliable company based in Penar...

From £21,200

Last active Aug 26
Get quotes

Penarth Loft Conversions Ltd

Bill Coslett

Location

Penarth, CF64

35 years in the trade and there is not much we haven't come across or done from pools to extensions and we specialise in loft conversions

From £21,600

Last active Jul 26
Get quotes

MARWAY BUILDING LTD

MARWAY BUILDING LTD is a trusted extension builder serving customers in Penarth and the surrounding area. Contact us to today to get a competitive ...

From £21,560

Last active Jul 26
Get quotes

Elite Building Contractors South Wales

Trusted and professional extension builder in Penarth. Experienced in all extension buildering work and keeping within budget and on quote. Elite B...

From £21,040

Last active Jul 26
Get quotes

PK CONSTRUCTION

Paul Knox

Trusted and professional extension builder in Penarth. Experienced in all extension buildering work and keeping within budget and on quote. PK CONS...

Flat roof extension cost in Penarth

Estimates for build a flat roof extension near Penarth

A flat roof extension ranges from the cheapest of £21,040 (PK CONSTRUCTION based in CF14) to the dearest of £22,240 (L.Jones Building based in CF62), 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 Penarth by posting a job with HaMuch. We'll send it to extension builders in Penarth.


Estimates for common extension builder jobs in Penarth;

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.

More extensions & conversions cost guides...