How Much Does an Extension Cost

The burning question

All construction projects are different and sadly there is no magic bullet for estimating the cost of an extension. 

If you search around the internet for advice in this area, you are likely to be disappointed with the end result. Most of them drastically over simplify the process and neglect key areas which can affect the cost significantly.

It is far better to ask people what they paid for their recent extensions than to rely on these sources. These will be real figures and you will be able to see what they acquired for the money.

We have created our own calculator below to aid you in getting a rough idea of what an extension might cost. However, the cost could easily be 20% above or below this figure depending on your specification and requirements, but also the building you are in.


This has been based on a single storey ground floor extension - if you are looking for a 2 storey extension add 50%. For lofts, it really is impossible to get an accurate figure without knowing the existing construction and structural detail involved. They are generally cheaper than rear extensions as you dont have to dig out new foundations and lay new concrete slabs.

If you are looking for an accurate price - do get in touch!