Bill of quantites

[Thedreamer]

Anybody got any good tips/advice for drawing up a bill of quantities?

 

[nod]

14 minutes ago, Thedreamer said:

Anybody got any good tips/advice for drawing up a bill of quantities?

 

Work out how much everything will cost and add 50%

[MikeSharp01]

38 minutes ago, nod said:

Work out how much everything will cost and add 50%

50% feels a bit high but the general principle is sound - it usually cost more than you think, if it was software I would double it, but for building the key patterns are well understood and you can peel this onion from the outside in. IE cost per square meter right down to the number of nails you need. You cannot do much until you have the basic data each of which sort of builds on the former:

1. Building design including standard of insulation and basic finishes - you will need that for planning anyway.
2. Floor area - from which flows the wall area, number and area of windows.
3. Standard of finish being targetted.
4. Systems - Heating / DHW / Environmental control - MVHR / PV / ????

On top of that you have a number of fiddle factors that you need to pop into your working out of quantities and costs, not all costs have quantities - you just need it once EG services connections, and some adjust everything EG site access / remoteness might increase delivery costs.

1. Site difficulty - steep slopes - leading to more civil engineering, remoteness from services - leading to high costs to run services, difficult access to site for plant.
2. How ECO you want / can afford to be.
3. Who is project managing - are you doing it yourself, or will you employ a PM.
4. How much you want the architect to do or if you want one at all.
5. How well organised can you be - sounds odd but if you can keep ahead of the project you will never slow it down and run up extra costs and if you don't change your mind about the layouts etc once the design is complete your control over the budget is likely tighter.

Have a look through the JSHarris blogs - he has a spreadsheet with all his costs broken down and if you get the latest copy of the housebuilders bible (by Mark Brinkley) the basic costs / bills of quantities are well explained there.

[PeterW]

You can get a QS online estimate for about £150. It takes a few hours to convert it to excel so you can play with it but they are pretty good as a start. 

 

A good QS is probably more important on a self build than on a lot of other projects unless you have an infinite budget ... 

[Ferdinand]

Read this thread to help you develop the necessary scepticism muscles and sense of guesstimating reality:

 

 

Edited January 7, 2018 by Ferdinand

[nod]

8 hours ago, nod said:

Work out how much everything will cost and add 50%

It’s sounds a lot But it’s very easy but it is so easy to under estimate both labour and materials 

I know this past year insulation has rocketed by 100 % at least Slates by Half that This time last blocks had a 40% rise added without much warning 

Brexit to blame Of course

I think most are taking advantage of how busy construction is 

and labour costs are still rising

Its very easy to cost every penny and be miles out

 

ove always thought that Architechs costing were ridiculously high But maybe they are looking worst case seneryo 

[Oz07]

Spoke to a demolition and reclamation bloke yesterday. He says he sells the pir insulation out of houses he demos dead easy. Said majority were full sheets too! Must've been on about cavity sheets

1 hour ago, nod said:

It’s sounds a lot But it’s very easy but it is so easy to under estimate both labour and materials 

I know this past year insulation has rocketed by 100 % at least Slates by Half that This time last blocks had a 40% rise added without much warning 

Brexit to blame Of course

I think most are taking advantage of how busy construction is 

and labour costs are still rising

Its very easy to cost every penny and be miles out

 

ove always thought that Architechs costing were ridiculously high But maybe they are looking worst case seneryo 

Spoke to a demolition and reclamation bloke yesterday. He says he sells the pir insulation out of houses he demos dead easy. Said majority were full sheets too! Must've been on about cavity sheets

[ToughButterCup]

11 hours ago, Thedreamer said:

Anybody got any good tips/advice for drawing up a bill of quantities?

 

No matter what the results of the costing exercise  are, don't acceptable any figure as accurate. Question each and every single one.

For example from our project: 

• QS cost for piling £22k - actually paid £6.5k.
• 5 expenditure headings which were never applied to the project (Total of about £7k)
• Wrong assumptions on the part of the QS (among them Muckaway never used,  some items on site already)
• Some expenditure headings missing.

And we paid for the QS' work! Bills of Quantities are useful as a general guide.  But no more. They are a small-scale  risk-reduction exercise

 

I now use a blend of SPONS, Internet research, asking here on BH, and local networking.

[Thedreamer]

Thank you all for your helpful replies, much appreciated.

 

Has anybody used this firm before Estimators Limited?

 

I also note that Jewson offer an estimating but perhaps this incurs a charge?

 

I have the Housebuilders bible it's a very interesting read. Gave me a good understanding of the various elements of the build.

 

[PeterW]

Estimators Ltd are ok - allow you to tweak online before you produce the price but can miss things

 

Most merchants offer a QS / BoM service but that is only half the answer - unless you have a copy of SPON, how long does it take to hang a door for example ..? That then drives your labour costs. 

 

 

[Thedreamer]

Thanks @PeterW my only concern is how much the estimate can be tweaked before submission. Our joiner will be stick building our kit, I wonder if this sort of thing can be taken into  account.