top of page


Anchor 1
Mouse Cottage Extension and Renovation E
extension and alterations-gmfbuilderspet


Are you thinking of building?

Got a project planned or just getting ideas and prices?




If you are located in and around Peterborough you can benefit from our Award winning building service.

Many years of experience, amazing quality of service, huge portfolio of proven work backed up with 'Trustmark' accreditation, and complete customer satisfaction make us the number 1 choice for your building needs in Peterborough



We understand how confusing the whole process can be so we are more than happy to talk through initial ideas and give you cost indications without obligation! 

Stages of an Extension

Second Fix:

Trade term for interior elements that are seen, this element can vary in cost dramatically based on the choice of 'finishing' items, typically includes

Electric sockets and switches- connection of fuseboard and safety certification

Fitting the boiler and radiators, connection to gas and certification

Doors, handles, architrave and skirting boards, bathroom installation and kitchen installation.



There is no limit to what you can spend when finishing the extension - every individual element will have a very different cost, from cheap carpet that is a few pounds per square metre, to the very best designer option that costs as much as the build itself! . Costs will also increase significantly if you are adding a new kitchen or bathroom to the extended space. 

First Fix:

Trade term for interior elements that are not normally seen again once the buildings complete such as the electrical wiring from the new fuseboard location, pipe runs from bathrooms and any other outlets back to the intended boiler location. Door frames or'linings' will be fitted and any internal stud walls and structural alterations.


The walls and ceilings are now covered in plasterboard or render, followed by corner trims/ beads and a skim coat of plaster finish

Barn Extension-gmfbuilderspeterborough (
Barn Extension-gmfbuilderspeterborough (



The preparing of the site and digging of foundations is essential to making sure the extension is built safely and with structural integrity. This phase is the most likely to bring surprise costs!  if there are complications at this stage, such as having to move drains or deal with tree roots(as we found here, even after trial holes there was a blanket of roots which meant additional depth required for the foundations), it can slow down the process and increase the cost.

The Shell:


This is where the main building takes place, building the basic structure with either brick and block or a timber frame. A roof is built, and windows are fitted to watertight the structure.

An extension  project goes through several stages of building, which i have demonstrated below with a two storey extension GMF Builders completed in 2019. Whatever stage your are at with your building, you can rely on us to get the project completed, without hassle or undue expense.

Barn Extension-gmfbuilderspeterborough (