Re: Re: 25sqm: Internal or External Measurement for Exempted Development??

Im not sure I understand what you mean by “They”. Is that the planning dept. you are referring to?

Can you say why you need a certificate or declaration

Edit: Sorry, forgot about the retention aspect of it. Not being nosey but how did you come to be in contact with the planning dept.?
Did they contact you re: unauthorised development or did you go to them looking for a declaration for mortgage purposes?

You referred to gross floor space in an earlier post. I always understood this to be the the total floor space inside the external walls but including all inner walls/partitions etc.