Planning confusion

11 Apr 2019
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United Kingdom
Dear All,
My first post, always a silent reader. We applied for certificate of lawful development for a side extension but our application was refused , reasons as follows;

vi) The proposed extension would adjoin the existing rear extension and so the maximum width of the dwelling would exceed half the width of the original dwelling house.

As the proposed extension adjoins the existing rear extension, it would have a maximum width of the dwelling that exceeds half the width of the original dwelling house. The application is recommended for refusal.

The enlarged part of the dwellinghouse would extend beyond a wall forming a side elevation of the original dwellinghouse, and would-
(i) exceed 4 metres in height,
(ii) have more than one storey, or

(ii) have a width greater than half the width of the original dwellinghouse; or YES

However we haven't gone past the side elevation of the house, which is the attached garage built in 1967 with the house, and is marked on the original deeds and forms one of the boundaries. The rear extension was added in the 70s.

What are we doing wrong here?

(i) should we just only ask to build the porch/side extension in front of the garage with a wall/gap? so it doesn't adjoin
(ii) try to reason that the garage is part of the original house (it was on the title deed plan we submitted and rest of estate has the same layout where not converted)
(iii) go for full planning?

Would appreciate any comments, feedback, ideas or how stupid I am :(

Many thanks everyone


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It's *any* side elevation rather than the one that's furthest from the house.

I'd look closely if they're including the width of the garage in their calculation of 'half the width of the original dwellinghouse' as this may help you get the width to <50%

Otherwise, full planning must be worth a go given that you already have the plans drawn so its just £200 and a 2 month delay.
Last edited:
Just a few thoughts here - hopefully others will chip in.

On balance I believe your LPA is incorrect in their interpretation.

On its own, the rear extension would today be caught out by A1(j) because it is more than1/2 the width of the house and extends beyond 'a wall forming a side elevation of the house' (this refers to the two-storey side wall).

There is also the rule that if an extension is built against another (post-original) extension, the whole extension is counted as one for Planning purposes. However, the front extension is built against an original part of the house, is not more than 1/2 the width of the house, and is not directly connected to the rear extension, so I would suggest this is not caught by A1(j).

I accept that you are altering the interior of the present garage to make it habitable space, but A1(j) only refers to 'the enlarged part', not any other part which is modified.

(The Planning Jungle website doesn't appear to refer to any appeal cases on this issue).
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Thank you garyo and tony1851, very much appreciate your most kind contributions. I will speak to the planning officer!

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