Permitted development for extensions (rear and side) and half width issues

[Matt Davey]

Hi there

 

We joined the forum yesterday and used our 'introduce' entry of the new members group to outline a question we have over permitted development rights and how rear and side extension potentially inter-relate. In hindsight, we probably put too long an entry and over-complicated our question, so we felt it was probably better to refine our ask and add it to this more specific group. So here it is....

 

To help describe the question we attach a visual representation of our wish here.

 

extension?

 

Basically, can rear extension 'A' cover the whole back part of the property as it does not join 'B'? In other words, as 'B' uses the full half width condition, does this use up allocation for 'A' in the rear

 

If it helps, our longer entry posted yesterday explains all other elements to our plot to pre-empt other questions which may follow to help get an answer to this. 

 

 

Really grateful for anyone who can help us understand the 50 page technical guidance issued around permitted development rights.

 

Thanks in anticipation.

 

 

Edited July 9, 2020 by Matt Davey

[DevilDamo]

PD relates to the ‘original’ house, which is not necessarily the ‘existing’. So assuming the part you label existing is infact original, then Part A is not PD as it’s greater than half the width of the house. Part B is PD and can be the full length/depth of the original house.

Edited July 9, 2020 by DevilDamo

[Ferdinand]

1 hour ago, DevilDamo said:

PD relates to the ‘original’ house, which is not necessarily the ‘existing’. So assuming the part you label existing is infact original, then Part A is not PD as it’s greater than half the width of the house. Part B is PD and can be the full length/depth of the original house.

 

AIUI understand it the half width rule applies to side extensions not back extensions, but this is ironically more discussed on the other thread. Ie the wrong one ?.

 

 

Edited July 9, 2020 by Ferdinand

[DevilDamo]

You’re right, it does. However, if the ‘existing’ house is ‘original’ then the rear infill would be checked against the PD rules for rear and side extensions. And again under PD, that rear elevation has two rear walls.

 

Under formal PP, it would just be deemed as a rear extension.

[Ferdinand]

1 hour ago, DevilDamo said:

You’re right, it does. However, if the ‘existing’ house is ‘original’ then the rear infill would be checked against the PD rules for rear and side extensions. And again under PD, that rear elevation has two rear walls.

 

Under formal PP, it would just be deemed as a rear extension.

 

My understanding is that the practice will be to use the main plane rather than the smaller plane,  and I think here the distinction is clear - and it is well within the 4m limit.

 

AIUI the interpretation may actually allow a further section projecting back to follow the extra bit using the same limit,  but I would need to check the dot and tittle.

[DevilDamo]

6 hours ago, Ferdinand said:

 

My understanding is that the practice will be to use the main plane rather than the smaller plane,  and I think here the distinction is clear - and it is well within the 4m limit.

 

AIUI the interpretation may actually allow a further section projecting back to follow the extra bit using the same limit,  but I would need to check the dot and tittle.

I’m not sure what you mean?

 

Rear infill extensions have to be checked against the PD rules for rear ‘and’ side extensions. It’s explained here...

 

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/830643/190910_Tech_Guide_for_publishing.pdf

(Page 23)

[Ferdinand]

1 hour ago, DevilDamo said:

I’m not sure what you mean?

 

Rear infill extensions have to be checked against the PD rules for rear ‘and’ side extensions. It’s explained here...

 

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/830643/190910_Tech_Guide_for_publishing.pdf

(Page 23)

 

Off to a hosp appointment, but see page 28 in your doc.

 

F 

[DevilDamo]

Yes but am not sure how that relates to the OP’s situation!?! Unless I’ve missed something somewhere in that the smaller rear projecting part (3.5 x 3.1m) is not original and is an existing extension? If that is the case, then Part A would be considered to be PD.

[ProDave]

You could always demolish the existing rear bit and rebuild it as part of the extension, that would be PD.  That would be my reply to any planning officer trying to enforce anything else.

[DevilDamo]

I’ve tried that before but the PO argued that I am now extending beyond a wall that is not original and has been built as a result of the partial demolition.

[Ferdinand]

1 hour ago, DevilDamo said:

Yes but am not sure how that relates to the OP’s situation!?! Unless I’ve missed something somewhere in that the smaller rear projecting part (3.5 x 3.1m) is not original and is an existing extension? If that is the case, then Part A would be considered to be PD.

OP says that the stepped out bit is original.

 

Point one third bullet  here:

 

[DevilDamo]

That would mean the infill/squaring off extension would be determined under both the rear and side PD rules and restrictions.

 

It comes up so much and many are refused CoL applications because of the understanding it is only a rear extension.

[Ferdinand]

On 10/07/2020 at 11:13, DevilDamo said:

That would mean the infill/squaring off extension would be determined under both the rear and side PD rules and restrictions.

 

It comes up so much and many are refused CoL applications because of the understanding it is only a rear extension.

I see your point (p24 in your doc), and I bet it has been done to death in case-law.

 

To me the rational interpretation is that something wholly behind a house should not be a "side extension", but that is not the case. Sometimes strange byways of Planning Law work well and sometimes not. Here - not.

 

F

 

[DevilDamo]

Agreed and is just one of the ‘clever’ ways PD can catch people out. The thing that comes up most is having a side extension and a rear extension under PD but linking them requires formal Planning.

 

If in the OP’s case we are only talking about a single storey rear/infill extension, there’s a 99% chance it’s sail through the formal Planning process anyway. But with that is a formal application, increased fees and a determination process.

[Matt Davey]

Thanks all for your valued input! We have come to the same conclusion; that the small protruding portion of original dwelling creates a rear & side PD extension issue, which in our instance hinders a rear full length extension. Should it not have ever been there, or have been a previous extension to the main dwelling -  we could have extended fully along the rear without challenge, what a silly quirk!

 

As such we are revising our scope to remove extension 'A' altogether, and increase the size of extension 'B' to finish flush with the rearmost section of the house. As we see it this would be fully compliant with PD for a side extension as it is less than half the width of the existing dwelling, and would still give us a similar square meter-age overall. Is this how you see it too, we would be interested to know? Thank you

 

[DevilDamo]

That is correct. You could increase the width by another 500mm if need be.

 

Any reason why you are wanting to go down the PD route as opposed to formal PP?

[Matt Davey]

If full planning offers any advantages then we would certainly consider going down that route but does this bring the risk the PO could reject, whereas under PD it would sail through? Our only additional concerns around getting approval via either process are:

 

1. that we want a good portion of full height triple-glazed windows (on the rear elevation) to the new extension. This is to make the most of the views but we have read that planning may be needed if windows differ ‘greatly’ from the original dwelling. Being an old bungalow the current ones are, in the most part, short and wide.

 

2. we should like to improve the tired old pebble dash render of the bugallow with either a smooth concrete render or a timber cladding. Which we would then use on the new extension for continuity. Perhaps even applying an external insulation to the bungalow first which has the smallest cavity walls known to man at the moment!
 

As for size; We opted for 9mx11m as this would keep us under the 100m2 CIL threshold....as well giving an approx 250m2 Total for the resulting house....which is more than big enough for our present and future needs

[DevilDamo]

The only advantages are that it would get what you want. Obviously with formal PP,  the proposals are reviewed against Planning policy while PD is more a checklist of widths, depths and heights. So yes, of course there is the possibility an application could be refused but is very rare for single storey extensions, especially those that are located towards the rear. During the course of the 8 week determination period, you’d liaise with the PO making sure there are no issues that could warrant a refusal. If there were to be any concerns and depending on how minor they would be, in the majority of situations, PO’s would offer you to submit revised drawings.

 

I’m not sure what you mean about needing windows to match. The majority at ground floor can be installed via PD anyway. When it’s not PD, then again... they’ll check the openings as per Planning policy but more importantly, privacy via overlooking. Ground floor windows on either elevation wouldn’t generally pose any privacy or overlooking issues especially as you could build a 2m high fence between properties without PP. The amount of openings does come under Building Control and could trigger a SAP calculation.

 

Changes to the external appearance via different materials that would not match existing would need to be dealt with via formal PP. Once you have gone through that process, you could build out the PD extension to match those new materials as they would then match existing.

 

Assuming this is a self-build or one you are to live in, you can claim exemption from CIL. There are certain caveats for this and one of them being you should not sell the property within 3 years after completion. If you do sell, you’ll have to pay the CIL for either the full or remaining term.

 

In terms of the submission of applications, you could submit a formal application for the rear infill extension and at the same time, submit a LDC application for the side extension as neither relate to one another. This would result in you only have one 8 week Planning process as opposed to two at 16 weeks.

[Matt Davey]

Thank you DevilDamo - this was a really helpful response and we follow all you say. Will look into the window opening point/SAP calculation you make as we've now plotted out our preferred window positions and sizes. Also, we'll make further checks on what we could do to the existing bungalow in terms of external cladding (maybe for insulation gain) and whether or not we could possibly avoid PP altogether, to then have the PD built extension fit in with existing. Thanks again!