Back extension - looking at inital budget

BobQ

What can you find out by other means. Your Land Registry might tell you the original builder. Are they still in existence? Do they have plans?

Does the local authority/water company have any plans of the sewers? Do your sewers connect directly to the street? Do your neighbours?

You could ask a neighbour about the drains in the immediate area?

Do you have an open drain and a stack pipe in the area you want to build? Or any manholes

Maybe there is no problem and the drainage is at the side of the house direct to the sewer? Have a look around.

rosie383

The only thing that I can add OP is that you need to contact the water company to find out if you need a build over agreement. It could be that whatever architect you are using will do that for you but we are doing it ourselves as it is very straightforward. If you are building within 2 (or 3 metres, I forget which) of a public sewer you need to apply for this. Even though the sewer doesn't run across the area where our extension is, it is just within the boundary for needing the agreement. Costs £636 where we are.
The architect technician has quoted us for detailed plans, and for putting in applications to the council and water company. In our area these applications are all very straightforward so we are doing those ourselves.

mishkanorman

Just wanted to return to this post as my builders have now completed their side of the build, as above we were quoted just shy of 40k and we've come in at exactly that. The finish and whole experience was exactly as we've hoped, the kitchen goes in at the start of next month and with that and plumbers/flooring we've spent an additional £12k.

Hopefully you can see the pictures here,

teneighty

Well it certainly looks big.

And at £1000/m2 (from dimensions given previously and total spend of £52,000) price seems about right.

rosie383

Thanks for the update!

iharding

Single storey extension, recently completed in Surrey. 5x6m external dimensions, flat roof with two large velux windows, including kitchen fitting (but not supply), power and lighting. Finished to unpainted plaster and bare screed floor. No interior doors or walls (open plan to existing ground floor). The price also included demolition of a small existing extension.

Price inc. VAT worked out at just over £2000/m2. We had one slightly lower quote and two significantly higher.