Flat roofs to single storey rear extensions make such ideal terraces it is surprising that you don’t see more of them. The problem is of course that it’s very hard to get planning consent for them. If you live in close proximity to your neighbours any sort of raised platform will overlook them and for that reason permission is normally refused.
But what about is you are buying a property and the owners are already using their flat roof as a terrace? How can you be sure that the local planning office won’t make you remove it if they find out?
The first step is to check whether the use is unlawful. Start by checking the original planning consent for the extension and see if any of the conditions prohibited the use of the flat roof as a terrace. These days the condition is virtually always inserted but that was not always the case. If the extension did not require planning consent i.e. it was a permitted development then it will be governed by The Town and Country Planning (General Permitted Development) Order 1995 which automatically excludes the construction or provision of balconies, verandas or raised platforms.
So what can you do if you think that the roof is being used as a terrace unlawfully by the current owner? Well, it all comes down to timing, the local planning office can take action against breaches of planning control arising from building operations for up to 4 years from the commencement of the breach. So if the owner has been enjoying the use of their flat roof as a terrace for more than 4 years the planning office have missed their chance and the owner can apply for a Certificate of Lawful Use.
Finally, what is the position if the terrace is being used by the owner of a converted flat rather than a house? The planning regulations are the same but the additional consideration relates to the Freeholder. Significant changes to a leaseholder’s demise will normally require a license from the Freeholder. The Freeholder cannot withhold consent unreasonably but it will be up to the leaseholder to prove that the new terrace will not have a detrimental effect on the building or the other leaseholders.