← Estimating fundamentals

Estimating fundamentals

Estimate assumptions, exclusions, and qualifications.

A well-prepared estimate includes not only costs but a clear statement of what has been assumed, what has been excluded, and any qualifications that affect the figures.

Who this guide is for

Every contractor producing estimates, particularly for clients who may not be familiar with construction scope boundaries. Essential for anyone who has experienced disputes over what was included.

Assumptions

Assumptions fill gaps where information was unavailable at estimating time. Examples: assumed cavity wall insulation specification, assumed foundation depth based on trial holes, assumed good ground conditions. Each assumption should be stated clearly so the client knows what has been priced.

Exclusions

Exclusions list what the estimate does not include. Common exclusions: VAT, planning fees, structural engineer fees, party wall agreements, utility connections, decoration beyond standard, and landscaping. An exclusion list protects both parties from misunderstanding.

Miniature example

"This estimate of £45,200 is based on the drawings dated 15/06/2026. Assumes existing services can be diverted without additional cost. Excludes: VAT, kitchen appliances, bathroom sanitaryware, and any unforeseen ground conditions. Valid for 30 days."

Common mistakes

• Omitting assumptions and leaving the client to guess what was priced
• Burying exclusions in small print rather than stating them upfront
• Not updating assumptions when new information becomes available