How Detailed Do Builders WANT An Extension Spec / Schedule To Be?

[EzioSuffolk]

Hi,

I'm having a rear extension built (architect has drawn plans), and soon want to contact builders for quotes etc. Expecting the build alone to be ~£80k+.

Currently, I've no building details/specifications whatsoever - just drawings of the brickwork (no drawings of how existing parts of the plumbing and drainage will need to be re-routed - which they will; nor drawings for gas piping/electrical cabling).

I want to keep costs down AND TO BE AS HELPFUL TO BUILDERS (probably a main contractor) AS POSSIBLE. I recognise that their time in creating quotes is valuable etc.



My question is:
Do builders / building contractors generally want the flexibility to 'design' and 'specify' the build themselves, and then quote for that [which presumably means each quote you get is for a somewhat different quality of materials and build]
OR
Do they prefer to work to a highly detailed specification, and quote to exactly that?


As I say, I want to ATTRACT some builders to the job, so don't want to approach things in a way that will immediately put many off.

My current idea is to employ a building contractor SOLELY to create a detailed specification (knowing that I won't be using them as the actual contractor), and then to 'give it' to other contractors to quote for.
But I certainly don't want to do this if many building contractors don't want to work to building plans specified by someone else.

Thanks for any advice

 

[^woody^]

How accurate do you want the price to be? And how many variations and unknown costs do you want to pay for?

 

[EzioSuffolk]

I want the price to be very accurate - a quote not an estimate.

From what I've read online, the best way to get a fair quote from a builder is to reduce their risks and guesswork. But I can't expect them to spend ages detailing and agreeing on a specification if they are 'only' preparing a quote, with no guarantee of the work. That's why I thought paying to have a detailed specn produced (and then tendering) would be (possibly) 'good for everyone'?

 

[tony1851]

It's unreasonable to expect an 'accurate' price, for the simple reason that the work required may change during the build.

To give one example: much depends on how detailed your plans are - some architects just do basic drawings for a planning application, but not necessarily suitable for Building Control purposes, or indeed to actually build from. Acres of cut-and-pasted specs at the side of the sheets are usually of little use in helping the builder to understand what's what.

If once you have dug your foundations trenches, and the inspector asks you for piled foundations instead of conventional strip foundations due to ground conditions, bang goes your accurate price - before you have even got out of the ground.

 

[Notch7]

I want the price to be very accurate - a quote not an estimate.

From what I've read online, the best way to get a fair quote from a builder is to reduce their risks and guesswork. But I can't expect them to spend ages detailing and agreeing on a specification if they are 'only' preparing a quote, with no guarantee of the work. That's why I thought paying to have a detailed specn produced (and then tendering) would be (possibly) 'good for everyone'?

In my experience the biggest problem is that builders dont warn clients of potential extra over costs that occur due to unforseen complications.
The most obvious is foundations, drainage and underground services. If you have shrinkable clay soil, hidden services, trees or hedges with the influence zone then you need to be thinking about extra foundation costs over and above the standard builders 1 metre deep footings spec.

The next unforseen extra costs are clients making slow decisions or design changes. Or indeed adding to the spec but not wanting to pay for it.

I would suggest whoever you choose, start with an agreement that any variations that influence price are costed and agreed in writing immediately, not argued after the event.

If you want a full schedule of works prepared go to an architect or QS. They can produce a spreadsheet list, which will be broken down into the trades.

If you want to do it yourself, get a building contract template.

There are recognised building contracts like the JCT for minor works.

 

[JohnD]

Having been both a specifier and a contractor, I can tell you that change control is where skilful contractors make their money.

"I want a 4 bedroom house please"
"Certainly, that'll be £804,792.16, plus any modifications will be extra at our normal rates."
(signed)
"Oh, can I have downlighters please?"
"Certainly, that's £12,00 extra"
"We do want a double sink in the kitchen"
"Certainly, that £2,600 extra"
"porch light"
"£900.23p"
"Brass doorknobs"
"£16,200"

Any of those could have been included in the original spec and price.

nothing pleased me more than looking through a detailed design and saying "oh, and you know we want x?" and seeing the supplier's PM immediately leafing through my requirement specification, and glumy noting that "x" is what I'd said before they quoted.

 

[^woody^]

I want the price to be very accurate

Then you need to give them detailed specification.

It's got noting to do with whether its a quote or an estimate.

But I can't expect them to spend ages detailing and agreeing on a specification

You dont 'agree' on anything. You tell them what you want them to to do and they tell you how much they will do it for.

 

[JohnD]

although preparing an accurate quote can be a substantial effort, and a contractor may not bother unless he believes it will be profitable and that he has at least a 1-in-3 chance of getting the contract (e.g. by early contractor pre-qualification before being given an invitation to tender)

Small builders can't be good at everything, and may decide to put their effort into something else.

 

[Notch7]

I personally wouldnt go to a main contractor for an £80k job, Id get a good one man band builder -he will an on the job tradesman and project manager.

 

[John D v2.0]

In our case we got an architect who produced a detailed 10ish page spec, and detailed drawings, all job specific and precise.
When the quotes came in they were all to differrent levels of care, but 3 were around 70k and 3 just over 100k.
We eventually went with the middle of the cheaper, but later I realised the cheaper quoted for something similar looking to the spec, and the higher 3 presumably quoted to build exactly.
It did kind of defeat the idea of a detailed spec.
There were some extras (structural issues) but we never did get to the bottom of that.
There was an issue with velux windows being missed off the quote, we paid as an extra and the builder quoted I think 350 pounds for the two, then they turned out to be the bottom end ones at 60 quid each from wickes, not the sound reducing ones specified.

My point being, yes write a detailed spec, but make sure you get the right level of detail and try to work out whether the builder really is following it. Our architect was more used to larger commercial project, so I think the level might have been higher than normal.

 

[Leofric]

Tell your architect you want to obtain quotations from builders and ask them to prepare a suitable specification and working drawings as necessary.
Depends how detailed you want the specification to be ! Don't waste a builders time asking them to prepare a specification .
Builders can quote from a building regulations approved construction specification but this leaves things open for 'variations'.
Discuss it with your architect , it shouldn't be necessary to go as far as employing a quantity surveyor for an £80,000 extension.

My current idea is to employ a building contractor SOLELY to create a detailed specification (knowing that I won't be using them as the actual contractor), and then to 'give it' to other contractors to quote for.

-NO, don't do that .

 

[JohnD]

-NO, don't do that .

He did say "employ"

So if he contracts with somebody to work as a consultant, preparing plans and documents, and to pay for that work only, with no expectation of winning a subsequent contract to build, he can.

What that cost? £500 an hour? I expect an architect's practice would be able to provide such a service. You can't expect to get it free. Some building firms might have staff experienced in the job, and available to hire.

 

[Leofric]

£500 an hour?

what is £500 an hour

So if he contracts with somebody to work as a consultant, preparing plans and documents, and to pay for that work only, with no expectation of winning a subsequent contract to build, he can.

He can do what he likes but aren't architects the people who usually prepare drawings and specifications rather than builders

 

[EzioSuffolk]

Thanks everyone for your thoughts.

My architect seems quite weak on detailing anything - perhaps a ‘Quantity Suveyor’ is the next person to help me produce a detailed spec. from which I can then get builders to quote?

My real question is, do many Building contractors LIKE to quote and work to a detailed specification like this?
How do I find those that do, as opposed those that prefer to keep things vague and ‘keep checking/refining with the client as they go along’?

 

[JP_]

I drew my own plans and happy with the result. It is the finishing bits and bobs that make the main difference.
You could ask for a building quote and electric / gas estimate, as this will possibly be outsourced anyway and will vary a lot depending on what you want.
I put all sockets, lights, rads etc on the plans I drew up, although the plumber needed glasses and had to come back to put in the rad he "didn't know was needed"...