Rear extension design & Plan

[plumbamateur]

Hi

I have been quoted £450 by a surveyor to draw up a design for a single storey, sloping roof rear kitchen extension for my mid-terrace house. The price includes calculations for the dimensions/specs of an RSJ to support the existing back wall. I've been told no planning permission will need to be sought, as it is permitted development.

I was wondering if the price sounds a little steep, given planning permission isn't required. Basically all I want is a plan to use to instruct a builder with; is this something that I could draw up myself? (No previous building experience, but I'd be confident doing a scale drawing). Do I really need a surveyor's plan?

Thanks.

 

[noseall]

£450 sounds ok to me. just let the builder and your designer get on with it. an accurate detailed drawing is essential for a good build, especially for accurate pricing. even on small jobs.

yes some of the stuff is copied from text, but do you want the responsibility?

don't try and do a structural engineers job though, this is very tricky stuff. not even architects mess with structural engineers.

 

[plumbamateur]

many thanks noseall

 

[Fluffster]

Am I right in thinking you will still need a detailed set of drawings for building control?
Pete

 

[^woody^]

Of course anyone can draw a scaled drawing, but do you know the specifications and requirements of the building regs?

Can you draw detailed sections and 1:10 details so that the plans get passed and your builder knows what to build without having to guess?

Is your builder going to quote you £28k in guesswork or £18k in precise knowledge of what needs to be done?

£450 is not at all bad - considering beam calcs are normally £100 each, and a site plan is £25

Many people begrudge £500 for some proper plans and then go on to pay a few £000 extra on the build price due to poor detailing and specification.

It's your money, but the good advice is to spend it where it matters

 

[plumbamateur]

Fluffster - yes, I believe so

woody - Good points well made - thanks. I think I was just a bit taken aback initially with the quotation, but when you start to think about it in these terms then it starts to make sense...

Thanks again.

 

[Willa]

How big is the extension? The reason I am asking is that BC would not ask for any calcs for an opening less than 2.0m and would accept standard lintels especially as if it is single storey, ie; catnics or similar. For £450 you should expect at least 3 A1 size drawings showing ground & rafter/joist plans with loads of sections and details complete with lintel and door schedules. This would take your designer at least one working week to do - don't be fobbed off with a couple of A3 size sheets.

 

[^woody^]

The sheet size is immaterial and not related to what is on them. The OP is not paying per sheet, and it is wrong to try and relate more sheets = more work done for the money

What is important is that the necessary information is on the plans.

From a practical point of view it is better for both building control and the builder to have all (or as much as possible) of the information on one sheet.

Its no good having one sheet with floor plans, another with elevations, another with sections, a handfull of detail sheets, and then a separate specification. It just causes major problems in finding information, cross referencing and spotting problems.

The only time I would produce more sheets, is for specialist trades (heating, electrics, kitchen fit etc) which can normally be left off the main build drawings. Everything else can fit on an A1 sheet