Getting the Cost Plan Right Before You Start Pricing

A cost plan isn't a one-off number

A cost plan isn't something you write once at tender stage and file away. It's a working document that follows the job from the first drawings through to the final account, and it only earns its keep if it's kept up to date as the job changes.

Building it in stages

Early on, when drawings are thin, the plan is broad: a figure per element based on what you know so far. As drawings develop and quantities firm up, that broad figure gets replaced with a proper elemental breakdown measured against NRM2, priced line by line rather than as a lump. By the time the job's on site, the plan should be detailed enough that a variation or a specification change can be slotted straight into the right element without reworking the whole thing.

Keeping it live once work starts

Once the job's running, the cost plan has to be checked against what's actually happening on site, not what was assumed at tender. Actual labour output, actual material costs, actual subcontractor prices. Where the numbers drift, you want to know in week three, not at the final account, when there's nothing left to do about it.

Where cost plans usually go wrong

The most common failure isn't bad arithmetic, it's a scope that was never properly nailed down. If nobody agreed exactly what's included and what isn't, the cost plan is built on sand no matter how carefully the sums are done. The second most common failure is poor communication between whoever built the plan and whoever's running the job, so the two drift apart without either side noticing until it's too late to fix cheaply.

Why it's worth the time

A cost plan that's actually maintained gives you an early warning system rather than a nasty surprise at the end. It tells you where the job is heading while there's still time to do something about it, rather than confirming what went wrong after the fact.

If you're putting a cost plan together and want it built properly from the start, send your drawings and we'll show you how it's structured.

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