Thirty years ago, most QS practices were still producing Bills of Quantities for most major projects. However the time involved in measurement and production of this detailed document has seen increased use of simplified Schedules of Work in their stead. As Quantity Surveyors, we are big fans of detail. The more detail that can be agreed and included into a contractual agreement the better, leaving less room for disagreement later on.
This is the aim of good contractual practice - with risks identified and dealt with at the business end of the contract, leaving a simple construction process with a happy and cohesive team. This is why most of our clients stick around, and why most builders we work with would happily do so again.
The below is a brief discussion on the benefits and drawbacks of using Bills of Quantities.
Schedule of Works or Bills of Quantities?
Bills of Quantities are a painstakingly detailed measurement of the proposed building works, which becomes a fairly hefty document to be priced by the builder.
A schedule of works is a simpler, un-quantified list of composite work items that prices are recorded next to.
Below is an example of how a simple, relatively inexpensive item like a door is dealt with, to illustrate the difference in approach.
Clearly the scheme of work is a lot less bulky, and easier to read. However it leaves the following issues:
1. What happens when the architrave is changed halfway through the job? With the scheme of work, only the builder knows what he originally allowed for in his price. Where there is uncertainty, there is the chance of dispute. With the Bill of Quants, you have an accurate breakdown of what was priced, so uplifting or decreasing the price becomes very simple and fair to both sides.
2. Let's say the drawings did not state that the door was a fire rated. The schedule of works gives no clue as to what was priced for and the builder can claim these works are ‘extra to the contract’. In the case of the Bill of Quantities the Quantity Surveyor has flagged all of the fire doors during measure, included an item which is priced in the BQ. No argument and no extra cost.
Bills of Quantities
Pros: Gives better financial control during the Construction works. When there are changes on the job (changes being inevitable during building works) the QS has a detailed list of the builder’s competitive rates which can be used to value the works. Valuing using these competitive rates is always cheaper than asking the builder to price works half way through the job.
The detailed process of measurement flushes out inconsistencies or omissions in the design, as the person measuring the work has to measure the works as though he were building them. This can help flag inefficient items. With a job that is currently under construction, a detailed measurement of the basement led us to flag an unusual steel reinforcement design in the basement. As QS we raised this with the engineer and knocked £12,000 of cost out of the design.
Cons: It takes circa 4 weeks to produce a Bill of Quantities, which can delay start on site. Bills are more expensive to produce than Schedules of Work.
Schedule of Works
Quicker to produce than a BQ, much easier to thumb through and understand at a glance. Produces a fairly thorough breakdown of costs, to ensure that the different Building Contractors have all priced ‘like for like’ bids. There is sufficient detail to see where the costs lie – i.e. The roof coverings are £X, the kitchen is £Y.
The quicker pricing can lead to work items being missed. This is never normally through intentional omission (at least not with reputable contractors!), it is just that the measurement and pricing process is more cursory. This can lead to arguments down the line, with the contractor asking for extra sums for works that the client feels he should have already included for within his price.
It is harder to unpack what the contractor has allowed for within ‘combined’ items. This makes it harder for the Quantity Surveyor to challenge varied costs effectively. Where there is uncertainty there can be arguments; particularly on cost.
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