Information needed before estimating.
A reliable estimate depends on having the right information. Without it, the estimator is guessing rather than calculating — and the project pays the price later.
Who this guide is for
Estimators gathering project information, contractors deciding whether to price a job, and clients who want to understand what the estimator needs from them.
Essential information sources
- Construction drawings (plans, sections, elevations, details)
- Specifications or workmanship schedules
- Site investigation reports (ground conditions, access)
- Existing services information (locations, capacities)
- Statutory requirements (planning conditions, building regulations)
- Client requirements brief (finishes, quality standards)
- Programme constraints and phasing requirements
Miniature example
An estimator reviewing a loft conversion enquiry checks: existing and proposed drawings, party wall surveyor's report, structural engineer's calcs, and a site access photo. Without the structural drawings, the estimator includes a provisional allowance for steelwork — flagged as an assumption.
Common mistakes
- Pricing from incomplete or outdated drawing sets
- Not visiting the site before estimating — missing access constraints
- Assuming standard conditions without checking ground or services information
Related guides and tools
Learn how to read drawings for estimating and about drawing registers. Use the Construction Estimator to organise your information.