Costs & quotations

What does ‘provisional sum’ mean in a roofing quotation?

Short answer: It is an allowance for work or quantity that cannot yet be confirmed, such as hidden timber repairs. The method for approval and pricing should be stated.

What this means in practice

Compare quotations line by line, including VAT, scaffold, waste, exact products, insulation, ventilation, leadwork, timber allowances, Building Control, payment terms and guarantees. A low total created by missing essential work is not a saving—it is an unpriced variation waiting to happen.

What to check next

  • Ask what evidence triggers the allowance
  • Agree rates where practical
  • Require approval before exceeding it

When should you ask a roofer to inspect it?

Get a measured, written quotation before committing to substantial work. Ask questions wherever wording is vague, and insist that hidden defects are photographed and priced for approval before extra work proceeds, except where immediate safety action is unavoidable.

Safety first: do not climb onto a roof without suitable access, training and protection. Keep clear of loose coverings, unstable ceilings and water near electrical fittings.

Technical content reviewJ & L Welch Roofing & Paving Services Ltd · Over 20 years of combined roofing experienceReviewed 28 August 2026 · How our answers are produced

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