Clarify 2.5m height planning rule for outbuildings
Discussion
So if one did want to dig down a little, all you need do is put your retaining wall in? Then measurement will be from top of said wall presumably?
On a slope for mine, so could easily lay one run of blocks and get 200mm of ceiling height which would be significant.
And yes probably should have just applied for planning but you figure it takes 8 weeks and it’ll be November...
On a slope for mine, so could easily lay one run of blocks and get 200mm of ceiling height which would be significant.
And yes probably should have just applied for planning but you figure it takes 8 weeks and it’ll be November...
Pheo said:
So if one did want to dig down a little, all you need do is put your retaining wall in? Then measurement will be from top of said wall presumably?
On a slope for mine, so could easily lay one run of blocks and get 200mm of ceiling height which would be significant.
And yes probably should have just applied for planning but you figure it takes 8 weeks and it’ll be November...
But you've been weighing up how to keep the design within permitted development for a couple of months so that's the planning permission time gone already.On a slope for mine, so could easily lay one run of blocks and get 200mm of ceiling height which would be significant.
And yes probably should have just applied for planning but you figure it takes 8 weeks and it’ll be November...
For foundations you usually dig down to solid ground with minimum depths to avoid problems with heave, tree roots and frost as well as ensuring that things like future service trenches don't disturb your building. Sheds just risk everything and if a corner sinks then just jack it up a bit. Gardens offices seem to be inbetween but for the prices that people pay I would have thought that it's worth good foundations.
If you build your retaining wall, or just dig down, for increased height consider drainage and flood prevention - where's the water table?
TA14 said:
But you've been weighing up how to keep the design within permitted development for a couple of months so that's the planning permission time gone already.
For foundations you usually dig down to solid ground with minimum depths to avoid problems with heave, tree roots and frost as well as ensuring that things like future service trenches don't disturb your building. Sheds just risk everything and if a corner sinks then just jack it up a bit. Gardens offices seem to be inbetween but for the prices that people pay I would have thought that it's worth good foundations.
If you build your retaining wall, or just dig down, for increased height consider drainage and flood prevention - where's the water table?
Well not really, I only decided to go with it in the last two weeks on the basis of I didn’t want to commit to the size and expense of something which is worthwhile building under planning.For foundations you usually dig down to solid ground with minimum depths to avoid problems with heave, tree roots and frost as well as ensuring that things like future service trenches don't disturb your building. Sheds just risk everything and if a corner sinks then just jack it up a bit. Gardens offices seem to be inbetween but for the prices that people pay I would have thought that it's worth good foundations.
If you build your retaining wall, or just dig down, for increased height consider drainage and flood prevention - where's the water table?
Re water table and drainage it’s a point, but it’s 200mm... I’ve got that on some of my paths around the house as a step down to ground level so I’m pretty sure water table isn’t going to cause that much of an issue?
Pheo said:
Then measurement will be from top of said wall presumably?
As above: the measurement will be from the highest pre-existing adjacent ground level.The (tanked) retaining wall should extend at least 150mm. above highest adjacent ground level, to link to the DPC.
Edited by Equus on Thursday 27th August 00:01
I applied for PP for a garage - plans cost £60 off the internet, about £40 or so for some OS and planning maps, then however much the actual application was with the council. Total cost about £300 maybe? Granted without objection.
Currently also going through planning for a house, obviously more complicated, but with a really good architect the whole process will still only be about £3k and that is including a proper site survey (£700+ VAT from memory).
Planning isn't hard or complicated, especially for an outbuilding. The worst thing is how long it takes for the council to do their stuff; the application for the house was submitted over 3 weeks ago and I've had nothing more than an acknowledgement. Apparently they are exceptionally busy at the moment all working from home. Garage was 8 weeks from submission to decision.
Currently also going through planning for a house, obviously more complicated, but with a really good architect the whole process will still only be about £3k and that is including a proper site survey (£700+ VAT from memory).
Planning isn't hard or complicated, especially for an outbuilding. The worst thing is how long it takes for the council to do their stuff; the application for the house was submitted over 3 weeks ago and I've had nothing more than an acknowledgement. Apparently they are exceptionally busy at the moment all working from home. Garage was 8 weeks from submission to decision.
https://www.thegardenroomguide.co.uk/wp-content/up...
Try this site, it gives you a diagram - ''a picture is worth a thousand words''
Try this site, it gives you a diagram - ''a picture is worth a thousand words''
Equus said:
BobSaunders said:
It's probably because the planning process is steeped in pain and suffering, and you never hear the good stories just the bad.
Also quite frankly one does not like it when others interfere in one's grand plan with their own perculiar vision of how one's castle should look (Planning, and NIMBY included).
I get the 'weekly lists' from a number of Local Authorities.Also quite frankly one does not like it when others interfere in one's grand plan with their own perculiar vision of how one's castle should look (Planning, and NIMBY included).
As an example from one that just happens to be sitting in my inbox at the moment: last week North Devon Council determined 51 applications; only 5 (ie. less than 1 in 10) were refused. A further one was withdrawn. Two of the refused ones literally made me laugh out loud when I opened the drawings to view. Two of the others were very clearly against national policy (so the agent, if not the applicant, should have known better). The remaining one, I actually had to look at all the drawings and think about it for more than 10 seconds, but having done so concluded that the LPA's decision was correct.
The reason I get the weekly lists is so that I can drum up business by looking at the refusals and contacting the applicants to say 'we can help you with that', if we think it's been a bad decision or something that could have been easily fixed.
9 times out of 10 my assessment is that it doesn't have, and never did have, a hope in hell. For that reason I firmly believe that the Planning system is necessary: it may be your 'castle', but that doesn't give you the right to inflict inappropriate and intrusive development on your neighbours.
good post as always Equus.I ended up on the planning committee of the local town council (toothless I know) after wriggling out of going on the council for years despite repeatedly being asked.
Frankly at times it was quite embarrassing watching what was going on. The councillors didn't seem to look at the PA's prior to the meeting (any yes like me they were lay people but with less idea).
They didn't have a clue what was going on mainly. I worked with the town clerk so I could flip things up on a large screen with Google maps with street view or earth etc just to try and give them some idea what they were supposed to be looking at and for especially within the regs etc.
Many of the decisions were nonsensical. I was sat through one 'controversial' app (they all were
) where all the nimbys and neighbours were out in force, (no one else cared) and after a discussion and a rejection (I was the only abstention rather than yes to save being lynched) the seasoned sensible long term councillor sat next to me whispered "never should an application gone through more than that one" after just voting against it.Thank goodness the real decisions were made elsewhere with a more pragmatic view.
Equus said:
As above: the measurement will be from the highest pre-existing adjacent ground level.
The (tanked) retaining wall should extend at least 150mm. above highest adjacent ground level, to link to the DPC.
Sorry thanks for clarifying.The (tanked) retaining wall should extend at least 150mm. above highest adjacent ground level, to link to the DPC.
Edited by Equus on Thursday 27th August 00:01
This implies retaining wall is part of the foundation structure of the building, I’m building on plinths so it would not be, Being essentially the other side of the plinth.
My one recollection of doing planning for our extension is it took ages, they kept resetting the clock, and took about 5 months and needed an architect. I think that’s what puts people off...
Pheo said:
This implies retaining wall is part of the foundation structure of the building, I’m building on plinths so it would not be, Being essentially the other side of the plinth.
In technical terms, we usually refer to 'substructure' (below DPC) and superstructure (above DPC), but I'm struggling to see the relevance in terms of Planning and PD?Equus said:
The (tanked) retaining wall should extend at least 150mm. above highest adjacent ground level, to link to the DPC.
Pheo said:
This implies retaining wall is part of the foundation structure of the building, I’m building on plinths so it would not be, Being essentially the other side of the plinth.
Equus said:
In technical terms, we usually refer to 'substructure' (below DPC) and superstructure (above DPC), but I'm struggling to see the relevance in terms of Planning and PD?
Cutting back the original ground, a retaining wall which is not part of the main structure only needs to be to ground level, and not necessarliy higher or tanked as you have stated, if it's just a straight or C shaped wall in plan view. Drainage and damp-proofing issues for the main building will have to be dealt with separately.I suppose that a retaining wall is 'works of an engineering nature' and so subject to planning anyway.
TA14 said:
Cutting back the original ground, a retaining wall which is not part of the main structure only needs to be to ground level, and not necessarliy higher or tanked as you have stated, if it's just a straight or C shaped wall in plan view. Drainage and damp-proofing issues for the main building will have to be dealt with separately.
I was assuming, since the whole purpose in the context of this discussion is to 'cheat' PD rules to give increased headroom, that the retained section will form part of the main building (ie. that it is the floor level of the building that is cut into the ground).I wouldn't be happy having a retaining wall tanked to ground level, then with an exposed (untanked) section between ground level and DPC. I think you need to link the two continuously as a matter of basic good practice. Unless it's some sort of very basic shed or carport structure where you're not worried about damp penetration, of course.
ETA: I might be misunderstanding what Pheo is trying to say about 'building on plinths' though.... but yes, if the retaining wall is an entirely separate structure to the building, it throws up questions of:
a) Whether the retaining wall is separate 'engineering work' that required permission in its own rights and;
b) Whether the retained ground is any longer immediately adjacent to the building, for the purposes of measuring the building's height.
Once again, it raises the question of whether you're trying to be so sharp you could cut yourself... if you're having to expend such a lot of devious effort to dodge through the precise wording of the rules, it probably means that you should just apply for Planning Permission and have done with it.
(apologies: edit overlapped with Pheo's post immediately below)
Edited by Equus on Thursday 27th August 09:57
I think you got it there TA14; it’s a small cutaway of 200mm at the top of the slope to just sit the top set of plinths in to bring the height down by 200mm. Ie one set of blocks. Along one edge of the building.
However it does sounds like a faff which is getting away from the original ease to your point, so probably not worth the bother.
I’ll post a picture when I’m back home on Sunday and I think you’ll guys might see why I’m asking.
However it does sounds like a faff which is getting away from the original ease to your point, so probably not worth the bother.
I’ll post a picture when I’m back home on Sunday and I think you’ll guys might see why I’m asking.
Equus said:
Pheo said:
This implies retaining wall is part of the foundation structure of the building, I’m building on plinths so it would not be, Being essentially the other side of the plinth.
In technical terms, we usually refer to 'substructure' (below DPC) and superstructure (above DPC), but I'm struggling to see the relevance in terms of Planning and PD?Permitted Development Technical Guide for Class E.1 (e) (iii) states "The height of the building, enclosure or container should be measured from the highest ground level immediately adjacent to the building, enclosure, or container to its highest point.".
Which means that when digging down to create a level site on sloping ground you need to have the ground touching the building, which means a tanked retaining wall adjacent to the building, something like this:
The red line indicates the "adjacent ground level" to be taken for the height calculation.
It would be easier, and make for a cheaper build, if it was possible to have a separate retaining wall, or even grade the slope so that a retaining wall wasn't necessary at all:
But I can't find any specific clarity on this. I am sure that the counter-example (of increasing the ground height by piling up new soil behind a building) wouldn't be accepted as changing the height calculation, so logically I would like to think that it was the original ground level which would be the key datum for the calculation. I am sure I found a document which stated that it was the "pre-existing ground level" but for the life of me I can't lay my hands on it now.
PhilboSE said:
...something like this:
Of course, in practical terms, it usually makes much more sense to simply build the structure on top of the retaining wall, instead of immediately in front of it, as shown on that diagram. Otherwise, apart from the fact that you're wasting space and money building two separate walls when one would do the job, you've got potential issues of damp penetration between the two.PhilboSE said:
...grade the slope so that a retaining wall wasn't necessary at all:
But I can't find any specific clarity on this. I am sure that the counter-example (of increasing the ground height by piling up new soil behind a building) wouldn't be accepted as changing the height calculation, so logically I would like to think that it was the original ground level which would be the key datum for the calculation. I am sure I found a document which stated that it was the "pre-existing ground level" but for the life of me I can't lay my hands on it now.
I'm not aware of any specific document that explicitly states "pre-existing ground level", but both common sense and the fact that shifting the soil would represent part of the 'development' as defined in Planning terms clearly suggest that this is the case.But I can't find any specific clarity on this. I am sure that the counter-example (of increasing the ground height by piling up new soil behind a building) wouldn't be accepted as changing the height calculation, so logically I would like to think that it was the original ground level which would be the key datum for the calculation. I am sure I found a document which stated that it was the "pre-existing ground level" but for the life of me I can't lay my hands on it now.
Obviously the problem is that you have no clear evidence of the pre-existing ground level after the development has taken place, but again common sense suggests that the way around this would be to seek a Certificate of Lawful Development prior to construction, providing survey details of existing ground levels along with 'proposed' drawings, including modified ground level.
But guess which is more complicated and costly... doing that (which requires and accurate topo survey related to a permanent datum) or simply applying for householder Planning Permission for a slightly taller-than-PD building?
You've also got the problem that the 'engineering work' involved with re-grading the levels as part of the 'development potentially (depending on extent) falls outside the scope of PD in itself.
I'm becoming boring by repetition, I know, but: how difficult is it worth making life for yourself for the satisfaction of having 'cheated' the system instead of submitting a straightforward householder Planning application?
Equus said:
Of course, in practical terms, it usually makes much more sense to simply build the structure on top of the retaining wall, instead of immediately in front of it, as shown on that diagram. Otherwise, apart from the fact that you're wasting space and money building two separate walls when one would do the job, you've got potential issues of damp penetration between the two.
True, but if the retaining wall forms part of the building then you have the issues of damp penetration and of course thermal bridging, lack of insulation, condensation etc anyway. For a garden room built "cheaply" it seems easier to me to keep the building and the retaining wall separate.Equus said:
Obviously the problem is that you have no clear evidence of the pre-existing ground level after the development has taken place, but again common sense suggests that the way around this would be to seek a Certificate of Lawful Development prior to construction, providing survey details of existing ground levels along with 'proposed' drawings, including modified ground level.
But guess which is more complicated and costly... doing that (which requires and accurate topo survey related to a permanent datum) or simply applying for householder Planning Permission for a slightly taller-than-PD building?
As it happens, I do have an accurate topo diagram as this is part of a landscaping project, and of course there are photographs and untouched ground elevations around the site which would support any assertion of original ground level. But I take your point, and as it happens I had actually concluded that a Certificate of Lawful Development might be the way to go.But guess which is more complicated and costly... doing that (which requires and accurate topo survey related to a permanent datum) or simply applying for householder Planning Permission for a slightly taller-than-PD building?
Equus said:
I'm becoming boring by repetition, I know, but: how difficult is it worth making life for yourself for the satisfaction of having 'cheated' the system instead of submitting a straightforward householder Planning application?
Fair enough, though if I can repeat myself, for my build, everything about my building falls within PD so I'm not trying to "cheat" any aspect of the system, just trying to determine the easiest means of construction. It comes down to the fact that I could make the build easier & cheaper (& probably more attractive) by getting either a Certificate of Lawful Development, or full PP. The issue with the latter is that I know my neighbour will object - I have zero concerns that this will be upheld as it's covered by PD anyway and he couldn't see the proposed building from any part of his property (and vice versa) - but I would just prefer to not have his 2 page diatribe recorded against my development for posterity.PhilboSE said:
...if I can repeat myself, for my build, everything about my building falls within PD ...
So apply for a certificate of lawfulness? Simples. 
But I would reiterate the point I made above, that alteration of existing ground levels and/or construction of a separate retaining wall may very well put the development outside the scope of PD in and of themselves.
And I should stress something else that I regularly say on this forum: if a proposal is PD, then a Local Authority cannot lawfully determine a Planning application for it and vice versa - if it does not meet the criteria for PD, by even the most trivial degree, they cannot issue a Certificate of Lawfulness on it. The two are mutually exclusive.
You (or the LPA) need to determine which of the two your proposed development is, and act accordingly.
If there is any doubt, the correct process would be to apply for a certificate of lawful development. If that is refused, you have two options:
1) Modify the design to address the reasons for refusal, and apply again, or;
2) Apply for Planning Permission
Yeah, so I don’t want to bother with significant geo engineering!! And if the retaining wall needs to form part of the building it’s a non starter.
I’ve done a terrible diagram to show you what I’m on about:
Top is plan view, second is elevation; the reason I’m asking is one corner of the site is high, and there is a sudden drop from the adjacent path, so I was thinking if I where to drop the plinth foundation down from this height by 200mm, it’d both be easier for me, and give me 200mm of height. However if as you say the two things must be connected it doesn’t work.
And I agree I could apply for planning, but a 8 week delay means building in November and another 8 weeks of working in the utility. Also I’m meant to not be trying to build too much and over do it!
I’ve done a terrible diagram to show you what I’m on about:
Top is plan view, second is elevation; the reason I’m asking is one corner of the site is high, and there is a sudden drop from the adjacent path, so I was thinking if I where to drop the plinth foundation down from this height by 200mm, it’d both be easier for me, and give me 200mm of height. However if as you say the two things must be connected it doesn’t work.
And I agree I could apply for planning, but a 8 week delay means building in November and another 8 weeks of working in the utility. Also I’m meant to not be trying to build too much and over do it!
Pheo said:
And I agree I could apply for planning, but a 8 week delay means building in November...
Do you feel lucky?There's a box to tick on the application form that asks you whether work has already started.
There's nothing to stop you ticking that box then carrying on regardless, at your own risk. Theoretically they have the power to serve a 'stop' notice on you, but it's most unlikely that they would.
Course, if the application is then refused, you're f
ked. Gassing Station | Homes, Gardens and DIY | Top of Page | What's New | My Stuff