When a contractor prices a job, there are two common approaches: a single lump sum, or a bill of quantities (BOQ) with a quantity and rate on every line. Lump sums are faster to prepare. But on electrical, instrumentation and other installation work, they cause problems that show up later, at claim time and when the project runs late.

The problem with lump sums

A lump sum tells the client what the whole job costs. It doesn’t say what any part of it is worth. That makes three things hard:

• Monthly claims. If the job is 40% done, which 40%? Without line items, progress becomes a percentage that someone has to estimate and someone else has to argue with.
• Variations. When scope is added or removed, there are no agreed rates to value the change, so every variation is a new negotiation.
• Delays. If the project is delayed, a contractor needs to show how much work was done and when. A lump sum gives no way to measure that, which weakens any extension of time claim.

Why the BOQ helps everyone

With a BOQ, every item has a quantity and a rate. Progress is measured, not estimated: 1,200 m of cable at the contract rate is a number both sides can check. Variations are valued at existing rates where they apply. And daily records of installed quantities show exactly what happened on site and when.

Separate supply from install

The biggest improvement is to price supply and installation separately on every line. Here’s why:

• Delivered but not installed: a switchboard on site is worth its supply value before a single cable is terminated. Separate rates let the contractor claim it fairly.
• Free-issue equipment: when the client supplies equipment such as instruments or transformers, the supply rate is simply zero and only installation is priced.
• Cleaner comparisons: at tender stage, the client can see whether one bidder is cheap on materials and expensive on labour, or the other way round.
• Better cash flow: materials are often the biggest early cost. Claiming supply separately means the contractor isn’t funding them for months.

Supply By and Install By

A good BOQ also says who supplies and who installs each item: the contractor, the client (free issue) or others. Items not in the contractor’s scope then drop out of the totals automatically, and there’s no argument later about what was included.

When a lump sum still makes sense

Small, well-defined jobs with little risk of change can be priced as a lump sum without much trouble. For anything larger, longer or likely to change, a BOQ pays for itself the first time a claim or variation is questioned.

Get started

Our Excel BOQ templates price supply and install separately on every line, with Supply By and Install By columns, pricing checks and tax for 17 countries. The rows match our Daily Progress Trackers and Payment Certificates, so the priced BOQ flows straight into each month’s claim.