- Project plans
- Project activities
- Legislation and standards
- Industry context
Last edited 17 Jun 2013
Contra proferentem is a rule of construction applying to written documents or deeds. The rule provides that if the wording of an agreement is ambiguous or uncertain, but not otherwise, the contract should be construed more strongly against the person whose words they are rather than the other party.
In the case of John Lee & Son (Grantham) Ltd v Railway Executive (1949) it was found that:
'We are presented with two alternative readings of this document and the reading which one should adopt is to be determined, amongst other things, by a consideration of the fact that the defendants put forward the document. They have put forward a clause which is by no means free from obscurity and have contended... that it has a remarkably, if not extravagantly, wide scope and I think that the rule contra proferentem should be applied’
If a party has incorporated its own standard terms and conditions of trade into an agreement then in the event of ambiguity those terms and conditions will be construed contra proferentem that party. Where however the parties execute standard form contracts, the contra proferentem rule will only operate in respect of amendments or additions to the contract.
 Find out more
 Related articles on Designing Buildings Wiki
Featured articles and news
Cutting-edge tech pairs with building management systems.
BSRIA updates its assessment of the industry.
What happens when it all goes wrong?
Input being gathered by CIOB.
Changes proposed for MHCLG consultation on house building statistics.
Full of passion and acerbic wit. 1 min book review.
Reminding us what is possible.
Five signs you are at risk.
Biotechnology as it applies to the built environment.
Stopping sound coming through windows.
Government response to the Building a Safer Future consultation.
Energy savings quickly payback any small additional capital investment.
Overbuild and air-space developments.