Combine two houses or flats – can I make 2 into 1 without planning permission?


As a general rule should not require permission to convert or combine two houses or flats into one as the works are internal and therefore not development according to the Town and Country Planning Act 1990. However some councils and in particular London boroughs are seeking to prevent this. They wish to avoid losing housing stock in their borough. So please read on!

You might also want to check any covenants or previous planning permission on the properties to see if they might prevent you from trying to combine two into one. 

Planning legislation (TCPA) states that where development does not result in a change in the use class of the property, planning permission is not required. This would appear to cover the position where two flats are combined into a single dwellinghouse: the use class was and remains C3 (dwellinghouses) and internal works do not require planning permission. 


combine two houses into one


However, the case of The London Borough of Richmond-upon-Thames v SSETR and Richmond-upon-Thames Churches Housing Trust [2000] 2 PLR 115 and an appeal in the Royal Borough of Kensington & Chelsea where they refused to issue a certificate of lawfulness, the  decisions have ruled that the “same use class” exception cannot be relied upon when you combine two dwellings. 

Over recent years local authorities are under pressure to deliver more dwellings in their local patch. This is obvious where the LPA is well below their 5 year housing target. As a result some local authorities, especially in London, have updated their local plan to not support the amalgamation of two or more flats or houses into one. This is why we have seen a couple of certificate of lawfulness and indeed other planning applications refused. 

Therefore if in London, especially the boroughs of Richmond-upon-Thames and Kensington & Chelsea you are likely to need a full planning permission. We can certainly assist with that. This is spreading to other areas.

Other local authorities are quite happy for two dwellings to be combined into one as they consider it not to be development. Especially outside of London, although South Hams in Devon refused a LDC in 2019 and this was also upheld at an appeal.

If the local authority hasn’t issued guidance on their website, you might like to contact them and ask. However you might opt not to disclose the property location. The vast majority will not have an issue if you wish to combine two houses or flats.

Once the two dwellings are converted into one, you might opt to apply for a certificate of lawfulness.

If you are in a listed building, you will need listed building consent before undertaking any internal works. if you are in a conservation area you may require permission before removing one of the two front doors.




Page Updated: 8th January 2024