Source: https://www.quantsurv.com/library/glossary/disallowed-cost
Content format: Markdown version of the public page.
Content reviewed: 2026-10-12

# Disallowed Cost

Cost excluded by the applicable NEC contract’s Disallowed Cost provisions; the definition, payment option, evidence and amendments determine the assessment.

by [Jack Butler-Kettle](<https://www.quantsurv.com/about#jack-butler-kettle>) · About 1 min readShare

## Further detail

Read this alongside [NEC guidance on Disallowed Cost](<https://www.neccontract.com/news/disallowed-costs-how-to-avoid-the-contractual-and-commercial-pitfalls>).

Disallowed Cost is a contractual category, not a general description of any cost the payer dislikes. Identify the applicable NEC form, edition, main option and amendments, then connect the proposed exclusion to the relevant wording and evidence. A cost appearing in a ledger is not enough to establish its treatment.

Keep the records needed to substantiate costs and identify disputed exclusions separately. Compare the supplier’s guidance on [Disallowed Cost under NEC contracts](<https://www.neccontract.com/news/disallowed-costs-how-to-avoid-the-contractual-and-commercial-pitfalls>) with your actual agreement, rather than importing a clause from another form or option. A [Signed contract review and action plan](<https://www.quantsurv.com/quantity-surveying?service=%2Fcontract-review%2Fservices%2Fpost-signing-contract-review#client-types>) can help identify the applicable cost provisions and the records needed to administer them.

## Sources

1.  [Disallowed costs: how to avoid the contractual and commercial pitfalls (1 October 2025)](<https://www.neccontract.com/news/disallowed-costs-how-to-avoid-the-contractual-and-commercial-pitfalls>). NEC Contracts.

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