Start from the building, not from a surface

Begin with the building use and plan, then divide the building into wall areas, roof areas and junctions. Each area gets its own description, because a wall question and a roof question rarely have the same answer.

Then list the openings: doors, windows, service penetrations and large equipment openings. Openings decide much of the envelope detailing, and they are the details most often missing from a first inquiry.

Then describe the services the envelope must support

Say whether the roof or wall must carry photovoltaic equipment, whether any interior needs a controlled environment, and how the building will be maintained. Each of these answers changes the envelope discussion, and each belongs in the first inquiry rather than in a later correction.

Finally, use the checklist below as the inquiry itself. Every item on it is a question to confirm, not a published figure, and the answers you receive are the basis for comparing suppliers.