Lending capital to a friend, contractual obligations

[Joshua Greenberg]

A friend of mine would like to borrow 90k to do a full reno on a project he has just purchased using another 90k he was able to acquire through a conventional mortgage. We have been friends for many years and I am concerned that my personal bias may interfere with the negotiation process. What are some standard protections that I should concern myself with including in the contract? Are there any tips that may help in facilitating the deal between two friends?