It is possible to have a term in the contract which excludes one of the parties from responsibility for something that may go wrong in the performance of the contract or limits that responsibility. It is called an exclusion clause or an exemption clause. For example, an exclusion from liability for damage done to the lawn by a builder's backhoe might be included in a contract between the builder and a home owner who is having an extension built to their home.
Express Terms of the Contract
The express terms of the contract, the obligations entered into by the parties, may be oral or set out in writing.
In addition, certain terms will be imposed upon the parties, most notably by statute under the Sale of Goods Act 1979 , The Sale of Goods (Implied Terms) Act 1973 and The Supply of Goods and Services Act 1982 The Sale and Supply of Goods to Consumers Regulations 2002 or by custom or by necessity. These terms are called ‘Implied Terms'.
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6.1.1 The Parol Evidence Rule
Oral evidence may not be adduced to add to, contradict or controvert a written document. The rule is part the law of evidence and applies not only to contracts but all kinds of documents. The rule grew up in the context of arguments about when parties would be allowed to place oral evidence before a jury. Much of the early case law involves wills.
Wikipedia note on Parol Evidence
Goss v Lord Nugent (1833) 5 B & Ad 58
“Verbal evidence is not allowed to be given...so as to add to or subtract from, or in any manner to vary or qualify the written contract.”
Rabin v Gerson Berger Association Ltd [1986] 1 WLR 526
The reasoning behind this is straightforward. Those who have bound themselves by a contract in writing should be bound by the written terms alone.
Hawkrish v Bank of Montreal (1969) 2 DLR (Rd) 600
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