Preliminary estimate or bill of quantities: which do I need?

Both are fully priced. The difference is when they are done, what they are built from, and what decisions they are meant to support.

Preliminary budget estimate

Done at the design and development stage, from scaled sketches or concept drawings. It is itemised per task and stage of construction in a summary you can read in a few minutes, and it exists to answer two questions early: can this project be built for the budget, and where is the money going?

Because it comes before the construction drawings, it is the cheapest point at which to change your mind. A roof form that costs more than it needs to, a footing system driven by the soil, a floor plan that wastes structure — these show up in the preliminary budget while they can still be fixed on paper. We can also suggest a more cost-effective construction method at this point, drawing on forty years of trade, manufacturing and supply experience.

Construction estimate with a bill of quantities

Done from the construction drawings, engineering and selections. Every material, labour item, good, service and percentage margin is priced, and the bill of quantities lists them per item and per task. It comes with a fully priced summary cost sheet containing all the costs required to complete the project.

It can be supplied priced, or as a non-priced bill of quantities for a contractor to price against when tendering. Either way it is the document you build, tender or borrow against. Fully priced estimates can be turned around in a few days, which gives a contractor time to adjust and submit a tender knowing every base is covered.

Which one do I need?

• Deciding whether to proceed, or comparing two designs: preliminary budget.
• Setting a budget to brief a designer or architect: preliminary budget.
• Tendering for a project, or checking tenders you have received: full construction estimate, priced or non-priced.
• Applying for construction finance: full construction estimate.
• Ordering materials, or quoting supply for a builder: a material take-off rather than either.
• A large or unusual project: both, in that order. The preliminary budget shapes the design; the full estimate prices what was drawn.

Not sure? Describe the project on the Request for Quotation form and we will recommend the right one when we quote.