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?

 

[^woody^]

Why have plans for a garage conversion? Do on a building notice, no plans, rely on builder knowing his stuff and depending on council, no calcs for opening

Or for plans £300 + £120 for the beam, so quote one is near enough

 

[jwl83]

Why have plans for a garage conversion? Do on a building notice, no plans, rely on builder knowing his stuff and depending on council, no calcs for opening

Or for plans £300 + £120 for the beam, so quote one is near enough

Thanks Woody.

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.

For reference, I've pasted an image below of existing/planned floorplans 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.

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?

 

[^woody^]

Have a search of the forum for building notice and contractors.

It does rely on the builder knowing his stuff and being trustworthy. There is an element of risk in this context, but this can be dealt with via a formal contract. Nothing fancy or wordy, just basic stuff covering who does what, when and for how much. They're are several homeowner contracts for this - not any builders own T&C's mind, but an independent standard contract.

Key thing is to have a detailed specification of the work in which you tell the builder what you want and what he needs to do, so things are clear. Even if you do have plans drawn, these will most often not have a detailed specification, just details of how to conform to building regulations - so not much use in this case.

At the least, get three quotes (not estimates) and ensure they are itemised so that you can see exactly what has and has not been priced for, and each can be compared like for like.

If you are not sure about engaging or checking builders or their work, I'd suggest that your money would be better spent not on plans, but on a surveyor advising/specifying the work, managing the work or just coming out and checking at certain times.

 

[tony1851]

I'm thinking of getting the next train out and setting up in London

 

[tony1851]

If it is a modern terrace house, are you sure you wouldn't need planning permission to convert the garage?
Some councils withdraw p.d. rights for garage conversions.

 

[^woody^]

I'm thinking of getting the next train out and setting up in London

When you get there, sub the work out to a bloke in Birmingham.

 

[blup]

The first quote seems reasonable, not just on the (comparative) price but because it breaks down the elements of the work and estimates the time spent (four hours) on the drawings.

Blup

 

[John D v2.0]

try to get an all inclusive quote with site visit and necessary inspection visits, we were advised to do that as otherwise they can string out a site visit into a full afternoon by the time they charge for travelling time. Our architect recommended getting them to include 3 site visits which were all needed in the end (initial which was already done anyway, 1 was redesign foundations as there weren't any existing, 2was inspect the lack of wall ties and other incorrect work, 3 was work out how to support the roof off existing 2 inch walls built on the floorboards + general report on the build quality of the roof)

 

[Leofric]

Even if you do have plans drawn, these will most often not have a detailed specification, just details of how to conform to building regulations - so not much use in this case.

Why would drawings showing details for bldg. regs approval not be much use in this case ? A more detailed specification based on the approved drawings would then :-

be a good way to keep the builders on the same page and get like-for-like quotes.

 

[noseall]

If it is a modern terrace house, are you sure you wouldn't need planning permission to convert the garage?
Some councils withdraw p.d. rights for garage conversions.

I was thinking the same thing. All the more contentious because of the area.

 

[Nige F]

I'm thinking of getting the next train out and setting up in London

Can you wait for HS2 ?

 

[^woody^]

Can you wait for HS2 ?

Going by the amount of work and materials on this near me, they will run out of money before they get north of Birmingham.

 

[^woody^]

Why would drawings showing details for bldg. regs approval not be much use in this case ? A more detailed specification based on the approved drawings would then :-

Because the amount of building regs design work in a conversion is .. a bit of damp proofing and a bit of insulation, and hey presto the drawings pass.

But what about the things that really matter to the homeowner ... heating, lighting, electric layouts, fixtures, fittings and finishes, layouts, best use of space etc ? None of that will go on a building regs drawing.

 

[Leofric]

Because the amount of building regs design work on the conversion is .. a bit of damp proofing and a bit of insulation, and hey presto the drawings pass.

Really , damn it , why was I doing all that work on the drawings for conversions for about 40 years . I know a more detailed specification is required when going out to tender but start off with drawings surely

layouts, best use of space etc ? None of that will go on a building regs drawing.

- bldg. regs drawings , i.e. proposed floor plans , show the layout and use of space don't they