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Hi, I am currently designing a rear extension to my end of terrace house that was built over 100 years ago. I’ve got 2 questions, firstly, the house used to have a rear toilet stuck on the very back of the house. This was demolished before I bought the house but I have found an old OS map from 2013 that shows it. Would the rear of the toilet be considered the rear of the ‘original house’ as it stood in 1947 even though it has been demolished for a few years? This is important as, when taking into account the toilet, the length of the extension is less than 3m meaning I can avoid prior approval. Secondly, are there any limits on the width of a rear extension? I know there is for side extensions but can’t see anything on rear extensions? The design is about 2/3 the width of the house. Thanks!

The ‘original’ date is 1st July 1948 so if the W.C. was added on after that date, then it would have been considered an extension.

If the W.C. was ‘original’ and has since been demolished and has been for at least four years, then I think you’ll have a case that you can now extend off the rear flush wall.

There are no limits to the widths of rear extensions. They have to obviously the rest of the PD criteria.