Building regs drawings for internal garage conversion - reasonable costs for London?

jwl83

I'm arranging structural calculations and building regs drawings for an internal garage conversion (including knocking through an internal structural wall to provide an open plan area). I've contacted several structural engineers and I'm getting drastically different estimates. The lowest is £590, the highest is £2,500 (all prices ex-VAT). What's a reasonable price for this kind of work? It's for a terraced house in outer London - the ground floor (including the space currently used by the garage) that'll be covered by the plans is 35m2.

I've had 4 estimates so far, here are the breakdowns I've been given:

£200 site visit +
£110 per beam/column calculation +
£70/hr drawing (4 hours expected)
£590 OVERALL

£1,500 OVERALL (no breakdown, but includes site visit, calculations and building regs drawings)

£300 initial inspection +
£450 the calculations and drawings for building regs
£750 OVERALL

£500 2 hour site visit (£250/hr)
£2,000 calculations & drawings
£2,500 OVERALL

What are people's experiences of prices for this kind of work in London?

Doozergirl

Do you have a builder?

Whilst the structural calcs are important for building regs, doing full drawings for a good builder is teaching granny to suck eggs.

It would form part of the contract if you don't know who you are employing, so helpful in that respect if you wnd up in court, but full drawings are likely to end up decorating the floor of the van after being looked at once.

We bring our SE from Bromsgrove to London and he's around your cheapest quote, if that, if we can tie him up while he's on another job.

jwl83

Thanks Doozergirl.

We haven't decided on a builder yet. We originally asked for estimates to renovate across the house, but what we got back proposed quite different approaches and were way over our budget (quotes were from £55k to £105k!). We decided to scale-back the scope of our work, to focus on the ground floor. We thought getting building regs drawings done would be a good way to keep the builders on the same page and get like-for-like quotes.

To give an idea of the scale of the work: Many of the internal walls are being removed (with steel to replace load bearing), french windows to back garden, new window and front door. I've drawn up a floor plan but I can't include it here due to forum rules.

Is this kind of work feasible on a building notice? Does anyone suggest good ways to review the prospective builders approaches without going for building regs drawings?