The document that I need has 'important' written at the top. The purpose of a defining relative clause is to clearly define who or what we are talking about. Without this information, it would be difficult to know who or what is meant. In this case it is not necessarily clear which house is being renovated. Mrs. Jackson, who is very intelligent, lives on the corner.
Correct punctuation is essential in non-defining relative clauses.
If the non-defining relative clause occurs in the middle of a sentence, a comma is put before the relative pronoun and at the end of the clause. If the non-defining relative clause occurs at the end of a sentence, a comma is put before the relative pronoun. In defining relative clauses there are no commas. PDP, Massachusetts Dept.of Ed. College credit avail.