Supersize Me* (*my build)

[RichA]

I have very recently purchased a house (Guildford BC) and am looking to do an extension to increase the size of my home. Architects/planners has said that under PP a max of 40%-50% increase in floor are is likely to be allowed ('Scale & Character' in Greenbelt).

Current is c1650 sqft (1400 'original'**) and would like to get to c2250 (+ loft) which equates to +60%. Therefore i would like to use PP and PD to overcome this limit.

I have spoken to a few architects re planning & drawings but think I need more specialist advice. Particularly as I have some concerns over my ability to best use PD.

1. Is there a way to use PD and PP to add 2 storey extension of more that 3m depth. e.g. apply for PP for 4m extension rear (left), build 3m PD extension rear right, then build previously approved 4m extension rear left? [Or if I go the 2-storey PD route am I effectively limited to 3m across the back).

2. How does a square bay window (purple) effect PD? Are the side walls of the bay classed as 'side walls'? (which would invalidate a 2-storey PD extension).

3. I have now discovered that there was a previous extension (1960s) to build up a cat-slide roof into a full room (yellow). How does this impact PD for a 2-storey rear extension? Is the 'original' rear wall taken at ground level, first floor level, or over the full rear section? e.g. does that limit PD at the rear left to just the GF -or- GF & 1F ?

Key: Black=existing. red= planned rear ext. green=planned porch. blue=potential side ext under PD, purple=bay window, yellow=1960s extension (formerly catslide roof), Pink=2-storey PD effected by yellow extension

Existing dimensions: here

Thanks.

 

[LukeB123]

1. Is there a way to use PD and PP to add 2 storey extension of more that 3m depth. e.g. apply for PP for 4m extension rear (left), build 3m PD extension rear right, then build previously approved 4m extension rear left? [Or if I go the 2-storey PD route am I effectively limited to 3m across the back

Probably not. To do this would rely on the new case law that Tony posted about a few weeks back assessing only the proposal in permitted development, rather than the extensions to the house as a whole. I haven't seen anyone use this new precedent and I think most LPA's are keeping to the old guidance until the Technical Guidance is updated; so I'll say no.

2. How does a square bay window (purple) effect PD? Are the side walls of the bay classed as 'side walls'? (which would invalidate a 2-storey PD extension).

Technically, probably yes. However, I think it would be VERY harsh on the LPA to pull you back on this though, I would hope they would avoid that as that isn't really the nature of what the legislation was to get at.

3. I have now discovered that there was a previous extension (1960s) to build up a cat-slide roof into a full room (yellow). How does this impact PD for a 2-storey rear extension? Is the 'original' rear wall taken at ground level, first floor level, or over the full rear section? e.g. does that limit PD at the rear left to just the GF -or- GF & 1F ?

The original rear wall is wherever the original rear walls are. The yellow bit would just be a first side extension and not extend off an original rear wall. The difficulty is when you start attaching things to it, either something single storey, or in this case the long 2 storey rear extension, creating a wrap around 2 storey extension that will need planning.

 

[RichA]

The original rear wall is wherever the original rear walls are. The yellow bit would just be a first side extension and not extend off an original rear wall. The difficulty is when you start attaching things to it, either something single storey, or in this case the long 2 storey rear extension, creating a wrap around 2 storey extension that will need planning.

But unlike a ground floor where there either is/isn't an existing rear wall, with this set up there is a partial rear wall. What constitutes the line of the rear of the property?

I have added a red line to show where the original rood finished. On the left (from the rear) there is a full height wall (at 2-story level), reducing to say 1 course of bricks on the right).

Does this mean that under PD can I do:
2-storey all the way across the back?, Or
2-storey as far as thw back door, then 1-storey from door to right wall.?

 

[LukeB123]

Yep got that, the area above the red line is a first floor side extension that's been added. The rear wall is measured from the original rear wall, wherever that is. So, if you aren't going past a rear wall then it's a side extension. In this case if you went 2 storey all across the back then you would be extending past an original rear wall with the first floor side extension (the "yellow" area" - the area above your red line would wrap around to both the side and the rear). The first floor extension would then extend beyond the original rear wall from below - Hope that clarifies the rear wall bit.

You definitely require permission for your point 1. You may be able to do point 2 (2 storey to door then single storey) as long as it doesn't touch previous extension.

This all obviously depends on the PD for 2 storey rears, such as set away from boundary walls etc etc which I haven't considered, which potentially may render this defunct anyway.

 

[RichA]

Thanks. I have updated my potential PD to as follows:

NB: House is detached. Set 3m from left boundary, 12m from right boundary, 20m from front boundary/road and 50+m from rear boundary.

This takes the property from approx 1400 sq ft to 2450 sq ft (+74% increase) so way over what I expect to be able to get under PP.

Is there anything I have missed?

I am considering applying for CLD for this; and then a planning app for a better designed variant with similar +74% uplift. What are my chances of this being successful?

 

[LukeB123]

R.E. is there anything you have missed - Sorry I have only just looked at your existing plans - I assume everything on the existing plan is original (except the first floor side yellow block?) Your proposed rear single storey extension (and as a result the 2 storey section) looks like it is extending off an original side wall (where the Sitting / Dining room is) so it would need consent being over 50% in width.

Difficult to say whether you're going to get permission for that - A lot of works to the original house..

 

[RichA]

R.E. is there anything you have missed - Sorry I have only just looked at your existing plans - I assume everything on the existing plan is original (except the first floor side yellow block?) Your proposed rear single storey extension (and as a result the 2 storey section) looks like it is extending off an original side wall (where the Sitting / Dining room is) so it would need consent being over 50% in width.

The GF rear projection is a 1970's extension. I am planning on demolishing and then re-building under PD. I have adjusted the latest plan.

It is a lot of works and straight up I would expect it to be rejected, but *hope* that a better design and a slightly smaller (just) footprint will allow the planning dept to justify an approval.

(Once I have CLD/Full approval I would like to go into loft under PD, and add 2x dormers).

 

[RichA]

FYI - To a follow up - this has now been approved (thanks for the assistance).

There are a couple of Points to note that may be of interest are:
1. Catslide roof - we argued that as the catslide roof is not a side wall, therefore the (yellow) 1960s extension does not extend off a side wall and is therefore not a wrap-around extension as not permitted by PD
2. Rear bay window - we argued that this was articulation of the rear wall, and not 2 side walls.
3. Roof - council made us amend roof so that the join was 'simpler' (more detail here)

Thanks, Rich


Key: Black=existing. red= planned rear ext. green=planned porch. blue=potential side ext under PD, purple=bay window, yellow=1960s extension (formerly catslide roof), Pink=2-storey PD effected by yellow extension

 

[garyo]

I'm scratching my head in terms of how the yellow extension doesn't form a side return just because it has a catslide roof? Was the recent case law mentioned?

Congratulations though!

 

[RichA]

Thanks.

"(j) the enlarged part of the dwellinghouse would extend beyond a wall forming a side elevation of the original dwellinghouse"

Our argument:

The roof alteration approved in 1961 changed the original catslide roof to a gable end. As such, the extension will not extend beyond "a wall forming a side elevation of the original dwellinghouse". The only original wall on the southern side of the dwelling is at ground floor level – there was no original first floor wall, only a catslide roof.

 

[tony1851]

(@LukeB123; DCLG have recently closed that loophole by revising the PD law; it now specifically states that when extending an extension,
the whole extension must comply with the PD rules).