Badgley

—Defendant Arden Van Upp (Van Upp) appeals from the trial court’s judgment in favor of plaintiff Laurence E. Badgley (Badgley). Van Upp raises several contentions on appeal, including the following: (1) the trial court should have sustained her demurrers to Badgley’s complaints on the grounds the subject matter of the complaints was subject to contractual arbitration and (2) the trial court’s reference of this case to a court commissioner to take all of the evidence was improper. We agree with the second contention and, accordingly, reverse the judgment and remand this case to the trial court for further consideration.

I. Factual and Procedural Background

The events leading up to this litigation began over 20 years ago. On July 10, 1973, Van Upp and Badgley entered into an agreement (the Agreement) to purchase residential property located at 2550 Webster Street in San Francisco (the Property) as tenants in common. According to the Agreement, the parties intended “to permit the use of certain rooms in the house by employees, long-term guests, or tenants” and “to use the house (and to permit the use of the house) for parties, gatherings, creative seminars, doctors’…