• The contract should spell out work to be performed, price, and draw schedule
• A working drawing should also be provided and agreed upon
• The contract should spell out how to handle extra work that may be required

Be Aware: It is common for a builder to collect extra work payment as extra work occurs. This is a benefit to the customer as the customer knows what things cost as spent, and eliminates a big bill of extras at the end of the project (for which you may not have budgeted).