Extension cost calculator
Want to add space and value to your home? Our ready reckoner, powered by the Build It Estimating Service, will help you gauge what size and style of extension will deliver the best result for your budget
Typical costs when adding space and value to your home
Whenever you take on a major home building project such as an extension, one of the first things you’ll want to figure out is just how much it’s likely to cost. Every build is different, of course, so the answer will depend on a host of considerations – including the size, number of storeys, type of roof structure, the quality of materials and finishes you want to specify, location and more.
The cost table and accompanying project advice in this article, prepared by the experts at the Build It Estimating Service, give you an insight into what you need to know when planning your extension budget. To help start your scheme off on the right foot, we’ve looked at five popular routes to adding space and value:
All of these routes hold the potential to transform your home and lifestyle. To make it easy for you to compare costs, we’ve focussed on 20m2 of extra floorplan for the single storey extension and loft conversion schemes, and 40m2 for the double-storey projects.
One thing you’ll notice is that, while the two-storey additions offer twice as much living space, you’re netting that extra floor area for much less than double the price. In other words, this route can give you fantastic value for money. Ultimately, however, exactly which option suits you will depend on your budget, ceiling values in the area and what type of extension fits your site and needs.
It’s worth bearing in mind that many extensions can be completed under permitted development rights – head to www.self-build.co.uk/pd to find out whether your scheme counts. Larger projects or those in protected areas will need formal planning permission.
Single storey flat roof extension Single storey lean-to extension Two storey flat roof extension Two storey apex roof extension Loft conversion with dormer