Homeowners undertake home extensions for various different reasons, but an increase in space is usually a common cause among clients. An increasing number of our clients are approaching us to ask about the feasibility of two storey extensions, so they can gain an extra bedroom on the first floor as well as lots of lovely living space on the ground floor. It is important to seek professional advice from your designer and think carefully about your design to ensure that your new space meets your requirements and uses space in an efficient way. Space is extremely valuable in property, especially in London. Here is some helpful information to keep in mind if you want to extend up, as well as out.

Age of the Property

The age of the property is actually surprisingly influential when it comes to gaining planning permission. The Victorians built their terraces to look the same from the front and the rear, repeating the shapes of the properties and architectural features. Some councils feel that this rhythm is important and that a simple single storey extension, let alone a two storey extension, breaks the rhythm. A more modern, post war house can experience more leniency because of its age, as it is not yet a heritage piece and quite often has more space around it.


A detached or semi-detached property have a big advantage as it doesn’t face as many issues when it comes to space, as they usually have bigger gardens. A two storey extension can be much more in keeping with the original style than a single storey.


One benefit of undertaking a two storey extension is that it can create savings all the way from the measured survey to the design and into the build stage. This is because the cost of the second measured survey is mitigated, as is the second call out cost for the builders, electricians and plumbers.  This works equally well if you are undertaking a ground floor extension and a loft conversion.

Flow of design

A two storey extension will require a level of reconfiguration. If you design the works in tandem, the rooms will be able to flow much better and the loss of a particular room, like a study, on the first floor could then be designed into the ground floor.


Depending on where you live, two storey extensions could either be relatively easy, or more challenging when it comes to gaining approval. Some councils will be concerned if you are giving your property the capability to be converted into flats, whilst others take a much more relaxed view. The diagram below is from Lambeth’s Supplementary Planning Documents which outlines what is and is not possible.

Two storey extensions depend on a lot of factors. If you want to discuss these in more detail as well as receiving a quote for the works, why not book in a site visit, which will answer all your questions.  Ring us today on 0207 495 6561 or email hello@buildteam.com to book a site visit with a member of our architectural team.