I wish to carry out extension of the detached property as follows;
1) Existing house is a detached house that has been extended in 1990 with planning permission for two storey side and rear by 3m on both ground and first floor.
2) I have now applied for 4m ground floor rear extension within original rear wall boundary line as under neighbourhood permitted development scheme and has been approved by the council.
3) I then applied for Legal Development certificate as suggested by my architect, who have ruled that the rear extension of further 4m is not lawful under neighbourhood permitted development scheme;
4) The reason is that the property already benefits from two storey side and rear extension, although it does not exceed any other limitations.
I would like your opinion on
a) Is this legally correct? – I have read all regulations and do not see this limitation mentioned anywhere.
b) Should I appeal at Bristol?
Thanks for your advice,

  • Mark Brinkley

    As you can see by the number of points you have made in framing your question, this is quite a complex question you are asking and I would have to be supremely confident in my own knowledge of the rules to give a definitive yes or no. I’m not.

    Hence the routine of using Lawful Development Certificates makes a lot of sense. If the council planners agree that what you are proposing doesn’t infringe your PD Rights, then you are in the clear. And if you ever come to sell the house, think how much easier it will be if you can produce said certificate. I wouldn’t bother appealing unless they disagree with you. Even then, you have the option of applying for planning permission.

  • Jan Slominski

    No. You need to read the 2008 amendments to the 1995 General Permitted Development Order. This clearly states that you can extend up to 4m (subject to other restrictions) from the rear elevation of the ORIGINAL dwelling house. As your proposal would be 8m beyond the original rear wall this would not be permitted development. If you read the 2013 amendments to the order, you’ll see provisions for a potential increase to 8m subject to a prior approval process. If you follow the correct process (which again is very clearly set out) and no neighbours object to the proposal, you may be able to extend up to 8m, again subject to some clearly set out restrictions. Hope that’s useful!


    Dear Mark and Jan,
    Thank you for comments to above.
    I have now received further clarification from Planning department with respect to application for ground floor rear extension within Permitted development neighbourhood scheme for a detached property that already benefits from two storey rear and side extension;
    The Barnet Planning department has confirmed following when a legal development certificate was applied for above extension;
    1) "It is not Lawful to carry out any further rear ground floor extension to a detached property(irrespective of size) within permitted neighbourhood scheme that benefits from an existing rear and side extension. Furthermore it does not matter the previous rear extension was carried out by obtaining Full planning application."
    As such they have refused LDC certificate even though they had originally granted permission to carry out same extension within PDNS scheme in September 2013.
    I have read the act and amendments and can not identify this ruling anywhere.
    Perhaps someone can clarify this.
    It would be valuable to me and other members.


    Hi Mark,
    Thanks for your reply.
    Just to update you:
    I had applied for rear ground floor extension up to 8m within PDNS ( Permitted Development Neighbourhood Scheme) In Aug 13 on detached property with existing side and rear two storey of 3m extension and was granted the permission in Oct 13.Subsequently I applied for LDC ( Legal development certificate) and it was dealt by the same council in NOV 13. I have today received the notification of refusal and also that notice of revocation of original approval on the ground that it is not legal to carry out this extension due to the fact that the property already benefits from two storey side and rear extension carried out in 1990 of 3m within approved planning permission.
    I find this decision strange due to.
    a)How is it possible for the same planning department to grant permission for identical circumstances in PSNS scheme and later refuse it under LDC without any changes in application?
    b) I can not find their reason for refusal in Act or amendment documents where it is stated that you can not carry out further extension of 4m to rear ground floor if the property already benefits from previous 3m rear ground floor extension within PDNS scheme .
    If you are aware of this in your experience or can point this out in the regulation, It will be of tremendous help.

  • Lesley Graham

    Hi Raj,

    I’m intending to do the same thing as you describe above. We have a detached house that has a double storey 3m extension and we want to extend further single storey. I called our local planning and asked for advice and was told the following: we could go out another 1m on the ground floor under permitted development and we could go out up to 8m via the neighbourhood consultation scheme. Even although that was the advice recieved on Monday I noted that the guidance on the planning portal suggest that a 3m double storey and 4m single storey is permitted development…..I like you am confused especially since i had already read your experience in theses posts. Just wondering now it’s 2.5 years on what happened next?

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