Larger rear extension

[banana12]

First post...and sorry it is so long ; your advice is very much appreciated!

Background: We live in a London suburb, semi detached house with an existing 3m rear extension (3.3m at eaves, a flat roof, built ~8 years ago).

We originally applied via full planning for a loft, 1st floor rear/side extension, and ground floor extension (further 3m), which was refused.

We reapplied with a more conservatively drawn loft and 1st floor only, for which permission was granted, and separately went through the neighbour consultation scheme (NCS) for ground floor extension; and have been informed prior approval is not required.

A few questions re proposed rear extension under PD- we were advised to reduce the eaves height of the existing 3m rear extension's flat roof to match new bit of extension otherwise it would not be PD as it will be considered 1 6m extension.

1) i am now reading RIDGE height can be up to 4 m as long as the eaves height is <3m. So could we have kept the existing 3.3height extension and done a pitched roof in the new part of the extension with a 3m eaves height, or would it not be allowed to have a section of flat roof higher than 3m? or alter the current flat roof entirely eg pitch the whole 6 m somehow. or any other sensible workarounds as I am not keen to reduce the height of the entire extension to 3m. i am mainly concerned that with a 6m flat roof the kitchen will feel quite low internally and not allow for enough light.
need some idea of what looks best for this larger extension externally / internally. note there is also first floor 3m extension planned spanning half the width (see plans) so not sure if this effects the ground floor extension roof design.

2) is there any particular order i need to do my build (eg ground floor under PD first, or 2story +loft extension granted under planning first, or either way?)

3) if we change the ground floor plan from what we submitted via NCS would we need to reapply to NCS/ or get a Lawful Development Certificate (LDC) with amended drawings , or just crack on with build as long as its PD?

4) is it advisable to get LDC anyways prior to build just in case as we are unclear re PD rules. this is what
our builders want to do

thanks so much!

 

[banana12]

Here are some plans for reference in case it helps to understand what we are doing ...

By the way for the kitchen extension , after some research we now plan for a fully open plan kitchen (unlike what is drawn) and keep the utilities in the garage where they are now (washer dryer). So we will build full rear width right up to our existing detached garage, thereby losing our side gate garden access, and insert a connecting internal fire rated door to attach the garage to the house. Again, i'm of the understanding that this is within my PD rights and therefore I can just go ahead and amend our plan without any further paperwork? (not planning to change the use of garage at all- just to introduce a new access point from inside the new kitchen).

 

[LukeB123]

could we have kept the existing 3m depth x 3.3height extension and added a pitched roof at the end of the extension to allow for a 3m eaves (bearing in mind this is a semi detached property so the extension is within 2m of the boundary wall). or would it not be allowed to have a 3m depth section of flat roof higher than 3m? so is it really necessary to reduce the height of the entire extension to 3m?

Unfortunately no you can't. The way the permitted development / NCS works is that everything you attach your new rear extension to must conform with permitted development rules. So your existing 3.3m eaves height extension TECHNICALLY, would not be able to be extended from whatsoever under the NCS because it exceeds the maximum eaves height of the regulations. - It is necessary to reduce (although a little silly) to meet the restrictions.

any sensible workarounds to this? i am mainly concerned that the kitchen will feel quite low internally and not allow for enough light.

You can go back in with a full planning application now that you have the fall back of the approval of the NCS, and see if the planning authority will look at a new full planning application pragmatically if you want to go through the cost / time.

2) second question is, is there any particular order i need to do my build (eg ground floor first?), bearing in mind that i have a part 2story +loft extension granted under planning, and a 6m rear extension not objected to under PD rights.

No. I assume that neither of these extensions physically attach to each other (sorry can't quite get my head around the plan.. it's early!) You just have to commence the full planning one with the details in the decision notice, and complete the single storey one within the timeframe on the associated decision notice.

3) is a 6 m flat roof a poor design choice?

I prefer a pitched roof or to have a small pitch generally, looks more aesthetically pleasing to me but each to their own.

4) if after sensible advice (hopefully!) we were feeling confident enough to improve our design and change the ground floor plan from what we submitted via NCS (if we thought it was still within PD) would we need to reapply to NCS or even just go straight for Lawful Planning Certificate with amended drawings , or just crack on with build?

It has to be done under the NCS again. It's not lawful development as it requires the NCS for approval (and the neighbours might choose to object at another time).

5) would you get LPC prior
to build just in case the sh*t hits
the fan and it's not PD after all

No, no point. If you build it exactly how it is approved, then it's got permission through the NCS anyway and a Lawful Development Certificate is going to give you no extra comfort. It's the councils fault if you build it as per the approved plan and it turns out their assessment was wrong and it does not fall within the NCS process - they've granted it permission.

 

[banana12]

Thanks so much for your detailed reply
So to summarise your view,
- yes i need to reduce the entire rear to 3m eaves if a flat roof
-i don't need to get a LDC prior to build, should just crack on

What about for our deviation from the plan submitted (in which we have not gone full width to allow for side gate garden access) as we are now hoping to go full width and attach the garage. would we need to reapply for NCS (the added width is not on the neighbours side if that helps)

Also, I keep seeing images like this which tells me that there are other options for the 6m flat roof. Not sure what they are doing here, maybe it is flat roof (3m eaves height) then the final 2m is pitched from a higher height? could this be an option for us?

 

[tony1851]

With regard to the ground floor rear extension only:
If you are building an extension on/against an existing extension, it would not be permitted development in any case and you could not use the NC scheme.
In this instance your LPA is wrong in their understanding of the rules.

 

[LukeB123]

- yes i need to reduce the entire rear to 3m eaves if a flat roof

Yep, see my first paragraph response and the initial advice given.

-i don't need to get a LDC prior to build, should just crack on

Yep, see my final paragraph response

What about for our deviation from the plan submitted (in which we have not gone full width to allow for side gate garden access) as we are now hoping to go full width and attach the garage. would we need to reapply for NCS (the added width is not on the neighbours side if that helps)

I don't think you can attach to the garage. The garage then becomes an extension to the house, rather than an outbuilding and your 6m extension will then become longer as it will include the garage as part of that extension to the house. You would need to reapply for the NCS, but I don't think it would meet the requirements based on this advice.

Also, I keep seeing images like this which tells me that there are other options for the 6m flat roof. Not sure what they are doing here, maybe it is flat roof (3m eaves height) then the final 2m is pitched from a higher height? could this be an option for us?

I am not 100% sure - more a building regs issue in terms of steels and spans and weights, so I wouldn't want to advise on this area.

If you are building an extension on/against an existing extension, it would not be permitted development in any case and you could not use the NC scheme.

I've had this wrangle and a lot of councils take the sensible approach of rather than just demolishing an extension, to build it back in exactly the same spot and add the NCS extension to it, they accept that building on an extension with the NCS (as long as the whole development falls under the requirements of the NCS) is permissible - indeed in this instance the O.P has already gained approval.

 

[tony1851]

I've had this wrangle and a lot of councils take the sensible approach of rather than just demolishing an extension, to build it back in exactly the same spot and add the NCS extension to it, they accept that building on an extension with the NCS (as long as the whole development falls under the requirements of the NCS) is permissible - indeed in this instance the O.P has already gained approval.

Agree entirely - but in my experience, many officers here are pedantic and refuse to accept applications on this basis, ridiculous as it is.

 

[banana12]

It has to be done under the NCS again. It's not lawful development as it requires the NCS for approval (and the neighbours might choose to object at another time).

Just found evidence/ confirmation of the above. If you do change the plan from what was supplied it has to be with written agreement from LPA. we will try to get this by letter (without reapplication via NCS) in the first instance since going full width on the non-shared boundary side has no impact on the neighbour as far as i can see. Maybe we can get an email from them saying this would be sufficient. Thank you for the advice

(11) The development must be carried out—

(a)where prior approval is required, in accordance with the details approved by the local planning authority;

(b)where prior approval is not required, or where sub-paragraph (10)(c) applies, in accordance with the information provided under sub-paragraph (2),

unless the local planning authority and the developer agree otherwise in writing

(2) Before beginning the development the developer must provide the following information to the local planning authority—

(a)a written description of the proposed development including—

(i)how far the enlarged part of the dwellinghouse extends beyond the rear wall of the original dwellinghouse;

(ii)the maximum height of the enlarged part of the dwellinghouse; and

(iii)the height of the eaves of the enlarged part of the dwellinghouse;

(b)a plan indicating the site and showing the proposed development;​