What are residential construction specifications? Construction drawings focus on a building's shape, appearance, and dimensions, while the written construction specifications, or specs, focus on what materials will be used and how they should be installed. In general, the more detail in the written specifications, the better.

At a minimum, building specifications list what materials to use, and call out any special installation requirements. Specs are much more valuable if they go further and provide detailed installation requirements and establish quality standards for the materials and the workmanship.