Planning a self build rear extension - guidance

[macadonald]

Hi Guys,

I know there have been many similar questions about rear extensions, but I was hoping for some general guidance with regard to planning a self build or project managed single storey rear extension to a 3 bed end of terraced 1930's house in SW London.

We are thinking about knocking down our old lean to rear extension, which is only half the width of the house and very old and replacing it with a new rear extension. From research, it would appear that I can build up to 3m out without needing planning permission and assuming all other requirements are met regarding neighbours right to light etc. Having read a couple of case studies, it sounds like the boundary line with the neighbour can cause some issues, which I'll need to talk to them about.

I like to think that I am a competent DIYer, so to save as much cost as possible, plan to get as hands on as I can with regard to labour and will probably dig the foundations, demolish the old and generally get as stuck in as I can..

Am I right in thinking the following are the correct steps with regard to planning this project:

1. Get the architect in to draw up the plans and give general guidance.
2. Structural engineer for the steel on the existing back wall (not spanning the entire width of the house, but will be supported half way). Or can the architect do this?
3. Notify council so they can inspect for building regs
4. Build over sewer license? This is a tricky one as we have sewers running along the back porches of the houses. I have the plans for the existing half rear extension, which show that there was a manhole cover, which has been properly replaced with a dual sealed cover etc and built over. When we bought the house the HIP showed plans from Thames Water with no manhole on our property. Stops at the neighbours, so not sure if the original alterations indicate this is no longer an issue.
5. Start building?

Is any one aware of any good books or sites for guidance on a similar project?
Could anyone perhaps breakdown the approx costs of the above planning stages?

Thanks in advance

 

[freddiemercurystwin]

If you build to within the Permitted Development rules then forget the 'Right to Light' issues you may have read about, same applies to 'boundary issues (obviously you cannot build over it). If it is Permitted Development then you can build it and nobody can stop you End of! http://www.planningportal.gov.uk/permission/commonprojects/extensions/

Worth a quick call to the planning department to check 'you have still got full permitted development rights on your property'.

Do not necessarily ignore making a planning application if you need more space and want to do something outside of Permitted development. Daft to go through all of this for the sake of a (comparatively) small amount of extra cash and time spent now on a planning application if the end result is better.

1) Unless you want something really mad there is no need to employ an architect. Use an architectural technician instead (usually cheaper for the same result).
2) Assuming an engineer is required, you can employ a structural engineer direct or preferably get the technician to appoint and liaise with him. Fees including structural engineer should be around £500-£1000 assuming the extension and engineering works are not a bit wacky or complicated. To get you a set of building regs drawings. Get a fixed fee and make sure you're gonna get more than just a rudimentary plan and a set of notes ie make sure its gonna be a decent set of drawings you end up with not just something that scrapes through the regs.
3) Building regs fees are typically around £400-600. This includes a fee to check the drawings and approve them and all of the inspections they need to make. You or the builder can call Building Control to make the inspections at the key stages.
4) If you need to get a Build Over agreement it can be a walkover or a nightmare. You can do this yourself or ask your technician to handle it. Having been stung once before on a job myself I only ever handle these on an hourly rate due to the unpredictable nature of them. You need to get the ball rolling on this early as you won't be able to do anything until its been approved although you'll need at least a rudimentary drawing to get the ball rolling. Costs vary depending on the Water Company.

If you're going to sell your house anytime soon consider a Certificate of Lawful Development as these are proof that the development did not require a full planning application. Without one and a nervous buyer/solicitor sometimes a house sale can be slowed up. http://www.planningportal.gov.uk/permission/next/lawfuldevelopmentcertificate

As well as the planning Portal, Local Authority Building Control and Planning websites have plenty of information about the procedures and the like.

 

[macadonald]

Thanks Freddy, a very good explanation.

I came accross this site earlier and have been reading through for a while. Looks very useful from a self build point of view. He takes you through every step of his build.

Possibly of interest to you and anyone else reading.

http://www.myhouseextension.com

 

[str]

macdonald, just had a read over your website - very good - very impressive finish on your extension.

just had an extension built last year, whic hwas phase 1 and am contenplating getting more involved in phase 2, which will be a single storey extension to the small kitchen we presently have.

Was thinking that I could definitely get involved in the foundations and the heavy work - not sure my block laying skills are up to par though.

 

[macadonald]

I wish that was my project, but was just pointing it out as being a useful and interesting read..

Managed to free up some cash on a remortgage, so hopign to get the abll rollign in the next month. Can anyone suggest an architectural technician in the SW london area who could possibly help draw up plans? Really trying to save as much money as I can on this job by planning it myslef.

Thanks