Get an Instant Estimate for Your House Extension

Use our simple Project Estimate Calculator to get a rough idea of your project costs. Just enter your requirements below for an instant estimate.

Extension estimator

Price your extension in about 60 seconds

Pick your extension type, slide the dimensions and choose your spec — we’ll show you a realistic guide price based on the rates we actually build to. No forms to fill in first.

A rough idea only. Every project is different — this tool gives a genuine guide price, not a quotation. Your accurate price comes after a proper survey.

What are you building?

Pick the closest match — you can tell us the detail later.

How big?

Slide to your rough overall dimensions — the plan and price update as you go.

Length 5 m

2 m14 m

Width 4 m

2 m10 m

inc. VAT · rough guide

Your footprint

Build your spec

The range covers low spec to high spec. Or start at low spec and tick the upgrades you’d want — we’ll tailor the figure.

Happy with your guide price?

Send us your details, drawings and photos and we’ll come back with an accurate estimate. No drawings yet? No problem — we offer a full design & build service.

Your guide price so far

Drawings & photos

Both optional — but the more we can see, the tighter the estimate.

Upload drawings (if you have them)

Architect plans, sketches, planning drawings — PDF, JPG or PNG

Upload photos of your property

The rear/side of the house, the garage, anywhere the work happens

No drawings yet? Ask about our design & build service — we handle drawings, planning and the build under one roof.

Any other works needed?

Tick anything that applies — we’ll include it in your accurate estimate.

Tell us more

Your details

We’ll only use these to talk to you about your project.

Name *

Please add your name

Phone *

Please add a contact number

Email *

Please add a valid email

Property address *

Please add the property address

Postcode

Where did you hear about us? *

Please tell us how you heard about Rosebrick

Anything else we should know?

By sending this you’re happy for Rosebrick Developments to contact you about your project. Nothing is binding — the guide price above is a rough guide only.

TESTIMONIALS

    
 
 
         
   Heather Priest 
 
 
 
 Trustindex verifies that the original source of the review is Google. Really professional company with great attention to detail. Polite and friendly and couldn’t have wished for a better job. Would highly recommend!
  
 
        
   Glenn Straw 
 
 
 
 Trustindex verifies that the original source of the review is Google. I had craig to build a small extension for me, glad I choose him excellent customer service, can't fault him one bit  exceptional quality, very polite and professional with respect for the property being occupied, left spotless at the end of everyday would definitely use again 👍
  
 
        
   Tom Smith 
 
 
 
 Trustindex verifies that the original source of the review is Google. The team at Rosebrick Developments did a fantastic job for us.
We had them in to deliver us works on a full house renovation, build us an exterior wall, and to complete all hard landscaping works and install a patio.

Professional from start to finish, would 100% recommend for those looking for high quality builders.
  
 
        
   david colley 
 
 
 
 Trustindex verifies that the original source of the review is Google. The team at Rosebrick Developments managed to overcome the awful elements to complete our wonderful kitchen extension on time and with nothing but perfection on the awkward details we had asked for to match the existing building.
Can not thank everyone for their brilliant work, hopefully the hit tea and biscuits helped cheer those very wet days a little!
  
 
        
   Anna Holt 
 
 
 
 Trustindex verifies that the original source of the review is Google. I recently used this building company for a garage extension, including installing roof lights and converting the roof from flat to an apex design, I've been extremely happy with the results. From the start to the final touches, the entire process was smooth, professional, and stress-free.
Communication was spot on. The quality of workmanship is outstanding, and everything was completed on time and within budget despite some very wet weather conditions as it was November!
It's clear they take real pride in their work.
Even the neighbours commented on how respectful they were and what a great job they had done. I would highly recommend them to anyone and always do!
  
 
        
   Jackie Andrews 
 
 
 
 Trustindex verifies that the original source of the review is Google. Great service nothing was too much Craig goes above and beyond
  
 
        
   Lee Harwood 
 
 
 
 Trustindex verifies that the original source of the review is Google. We are extremely happy with the patio built by Rose Brick Developments. From the initial consultation to completion, everything was handled professionally and efficiently. Craig and the team were reliable, easy to communicate with, and paid close attention to detail. The quality of workmanship is excellent, and the patio has completely transformed our outdoor space. The project was completed on time and exactly as promised. We would highly recommend Rose Brick Developments to anyone looking for high-quality work and outstanding service.
  
 
        
   Craig Swain 
 
 
 
 Trustindex verifies that the original source of the review is Google. Rosebrick Developments recently built an extension for us, and we are absolutely amazed by the finished result. The team worked to the highest standards with outstanding professionalism throughout the entire project.

They kept us updated daily on progress and were always accommodating, ensuring all our needs were met from start to finish. Nothing was ever too much trouble, and their attention to detail really shows in the final product.

I cannot recommend Rosebrick Developments highly enough and will definitely be using them again for any future building work. If you’re looking for a trusted, reliable builder who truly goes above and beyond for their customers, look no further.

Thank you to everyone at Rosebrick Developments for our wonderful extension — we couldn’t be happier 😁
  
 
  
  
 
 
      Verified by Trustindex  Trustindex verified badge is the Universal Symbol of Trust. Only the greatest companies can get the verified badge who has a review score above 4.5, based on customer reviews over the past 12 months. Read more