Modified bitumen describes a family of roof systems, not one universal installation. Layer configuration, attachment, surface treatment, and substrate conditions can vary. The proposal should identify the complete system being priced.
What to do next
Ask which products and installation method are included and how transitions will be handled. Compare removal, substrate repair, and perimeter details across bids. Keep any limitations on occupied-building operations visible before approving the work.
Related Perkins guidance
Contact Perkins Roofing to discuss your roof and the appropriate next step.