Building regs application: How much detail?

[JonHowes]

Hi, This has probably been answered before although I can't find the information:

I've gained planning permission for a large workshop in my garden. It is over 50 square metres so needs building regs approval. I want to get on with the build and am wondering how much detail normally goes into a building regs application for a project like this.

It is a timber structure skinned with trad corrugated steel. I've done structural calcs for base, wall and roof and written these up including a finite element analysis of some truss beams needed for the roof (I'm an Aero-Engineer so this is home territory).

I've prepared construction drawings of most elements such as base, frames, skinning, structural details etc and also a rough drainage scheme (sloping plot)

Although I have outlined routing of wiring I have not done anything on electrical compliance as I am hiring a specialist for this. Other than making sure that there is space for wires in the right places this aspect will not be ready until later in the build.

The building control application isn't clear about the minimum acceptable level of detail. Can anyone advise? Does it cause a major issue if the detail isn't complete on initial application?

Thanks in advance for any help.

Jon

 

[Jacob]

Do as much as you need for your own purposes, for planners and for your builder and then check it out with BC dept. They'll let you know what else they'd want to see, they tend to be very helpful.

 

[Sandyn]

You might find that building control will not be interested in any calculations. They may just need the truss's to be supplied by an accredited manufacturer.
The warrant which was done for my extension, didn't really have a great deal of detail. Wiring was just shown as single lines and squares, but it had to meet the relevant regulations. They are more interested that the finished product meets all the relevant regulations and you have some way of proving it either by inspection by an approved tester or supplied by an approved manufacturer.
They will be interested in position of the building within your boundary and height, also how you will connect to drains. You could get a copy of a similar application to see what detail it contained, but as Jacob says, speak to building control, they are normally very helpful and usually appreciate you talk to them first.

 

[JonHowes]

Thanks for this Jacob and Sandyn.

The roof truss ( a pair of parallel beams running the length of the building under a clerestory) will be built on site. They've been designed to extremely conservative stresses and bonding allowables (safety factor >5 pretty much everywhere against maximum design derived load from building regs with over-specced timber grade) so we'll see how that goes.

There is no water supply to the building so it's only surface water that is of concern (plus what lands on the roof). I'm planning a drainage gulley all around the building to soak away on the downslope. I have a drawing of that.

Thanks for the tips, looks like the best bet is to get it in and await an initial review.

 

[Jameshow]

Do you have professional indemnity insurance for the designed beams? I think the council will want calcs done by insured engineer.....

Not that you couldn't do the calcs...

 

[Jones]

You can usually do full plans or inspection for building regulations, the cost is the same here. Full plans should have all the details including calcs and theoretically the plan is passed, you build to plan and it's ok, though they'll usually inspect as well. If you go the inspection route someone will come and inspect the relevant sections as you do it and will often offer advice on what they want to see. They will always check calcs whoever has done them. Electrical work must be signed off by someone qualified though an electrician may be happy for you to run cable for them. If you're not used to doing full plans then the inspection route will be easier.

 

[Lons]

The BCO won't be too pedantic because it's a non habitable build, as long as it's for personal use and not commercial / no employees. he won't be bothered about location or roof height either as that's a planning issue. Electrics and other utilities, rainwater disposal etc. are a different matter but you have that covered and as long as your structural details are sound and within tolerance they will be happy to work along with you. The will want to see any underground work and foundations before covered up so be sure that's done correctly or you could be asked to excavate for later inspection.
The guys usually just want an easy life and are there to help you achieve what you've planned though you can come across an occasional pr+tt

 

[Lazurus]

As above, my BCO was extremely helpful, popped out to look at the footings, again for the roof his next and last visit will be to inspect drainage (not rain water) before back filling.

 

[JonHowes]

Thanks all, very helpful indeed.

As for professional indemnity insurance, yes, I run an Aerospace engineering consultancy so carry insurance for that. Since much of the work is the classical Engineer's problem of receiving modest thanks or killing hundreds of innocent people insurance isn't really optional!