When it comes to roofs always have the contractor measure. Bluebook assumptions when measuring a roof in RepairBase: We use a 5/12 pitch for moderate slope, 8/12 pitch for steep roofs, and include a 2 foot overhang. We assume a garage sf is 200 sf per car and an attached garage has no living area above it and an enclosed garage does. Covered balconies, covered porches, and roof covered patios will have an impact on the roof measurements. Roof pitch and Roof footprint variances can greatly affect the roof measurement. Dormers can impact the roof measurements.
There are many variable when it comes measuring roofs accurately. We give you an estimate based on common roof pitches and common garage sf. Roof Footprint is a calculation based on living area, # of stories, attached garage and enclosed garage. The biggest variance can happen when any one of these variables are incorrect.
To answer the question regarding the items we do not have in RepairBase. Please send the list of items to us and we will have our research department get started on them.