Single Storey Rear Extension on a sloping garden (w/Drawings)

As you are doing your own drawings the only cost will be the £206 planning fee which is nothing in context to the other costs of building.

While there is nothing wrong with a flat roof, there is with a needless step down and overall "fitting in" with the house.

I can't see why you would want to compromise a design that you have to live with and may be a future issue with any buyer for the sake of trying to jig the design to a restrictive PD criteria.

@Aeron Rees

If I am understanding correctly;

• Planning permission route: Householder planning permission via Planning portal online application =£206 -> Building Control application via Planning portal online application = £360. Total = £566
• Building Control route: Building Control application via Planning portal online application. Total = £360

I've read that a Lawful Development Certificate is optional so i'm not sure to include that to the costs.
And as you said, this difference is a relatively small amount in the grand scheme of things and compromises the extensions designs, so I'm swaying towards the planning permission route.

@ ^woody^

I am in agreement with you woody, however there is one thing I am wondering.
Hypothetically; if Planning Permission is denied, how much of the decision would be final i.e. how much leniency and negotiability am I potentially give. I assume the £206 if not refunded of course, but would it be back to the drawing board, reapplying and paying the £206 fee until approval?
And also I was just curious, If it is approved, why is it necessary to apply to building control if planning is already approved?

Your council will have a specific planning policy for extensions. Have a look for it. This will contain design guides of what is and is not acceptable to them. Design in accordance with the policy and the extension must be approved. Design outside the guidelines and there is some leeway for minor deviations, but not much, otherwise it must be refused. But there is always some subjectivity with what is and is not acceptable.

The most common factor for ground floor extension refusals is the so-called 45° rule relating to light to a neighbours window. Otherwise there is not much to refuse a ground floor extension on.

As part of the assessment, if there are things the planners don't like, then you will be given the chance to alter the plans or withdraw the application. If the application gets refused, then you can resubmit a revised scheme for free, and/or you can appeal the decision to the planning inspectorate if you think the council was wrong.

But the idea is that you do your homework and only submit an application that has a good chance of being approved. Unless you really want to test what you think is an unacceptable or restrictive planning policy.

Planning permission (permission to build) and building regulation approval (how to build) are two different things.

With regards to Planning, regardless of the LPA decision you get 'one-free-go', as long as the second application is within the stated timeframe and for the same kind of thing as the first.

I'll proceed with planning permission and hope everything will be approved with my current drawings.
Thanks everyone, your help has been invaluable.

P.S. For future questions, would it be appropriate to open a new thread or continue on with this one?

New thread. Every time.

It’s worth ringing the Local Planning Authority and asking if they have a home extensions guide, a lot of authorities have home extension guides that basically deal with things like the 45° rule and other factors such as the need for matching materials etc.

See link to example guidance, Gloucester City Council, an Authority I deal with a lot. See page 21 onwards with regard to the 45° rule. This is a standard rule, and will be the kind of thing your authority will apply to your extension.

http://www.gloucester.gov.uk/reside... Building Control/UrbanDesign/HEG IA 0808.pdf

If your application was refused, you could always just go down the CLD route anyway, and just get the extension that way. I have dealt with a fair few single storey extensions, and not had any refused yet. The Authority will usually ring you anyway as opposed to refusing it outright and ask for amendments, if possible.

I think most of the other stuff that you required has been covered by others, best of luck and if you need any other advice please feel free to contact me.