Most building code provisions are “prescriptive,” meaning that they lay out a recipe for the work, with specifications for both the material and installation. For example, a prescriptive code for roof sheathing nailing states that the plywood must be secured with eight-penny ring-shank nails at a maximum spacing of six inches apart.

    Most of sections of the building codes are prescriptive, but some are performance-based. Instead of specifying a method of construction, a performance code provision allows a manufacturer to create a new building product utilizing the latest technology and materials, and then have it approved by the building code, after meeting specified safety and performance standards. 

   An example of a performance provision would be one of Miami-Dade County’s standards for approving storm shutters in the wind-blown debris zone of South Florida. The shutter must survive being struck at a test lab with a nine-pound 2x4 piece of lumber shot into it at 50 mph. Much of the HUD-code for mobile homes is also prescriptive.

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To learn more about exterior walls and structures, see these other blog posts:

• What is the average lifespan of a house foundation?

• What causes vertical cracks in fiber cement siding planks?

• What causes raised white lines of residue on a block wall that are crusty and crumbling? 

• What is the difference between soil subsidence, heave, creep, and settlement? 

• How much ventilation is required for the under-floor crawl space of a home? 

• What causes stair-step cracks in a block or brick wall?

• What causes a horizontal crack in a block or brick wall? 

• How can I tell if a diagonal crack in drywall at the corner of a window or door indicates a structural problem?

• What causes the surface of old bricks to erode away into sandy powder? 

• What are the pros and cons of concrete block versus wood frame construction?

• Should I buy a house with a crawl space? 

• Why is my stucco cracking?

• There's cracks running along the home's concrete tie beam. What's wrong? 

• What would cause long horizontal lines of brick mortar to fall out?

• How do I recognize serious structural problems in a house?

• What is engineered wood siding?

• Should I buy a house that has had foundation repair? 

• What is a "continuous load path”?

• Should I buy a house with asbestos siding?   

• How can I tell if cracks in the garage floor are a problem or not? 

• What do you look for when inspecting vinyl siding?

• Why is housewrap installed on exterior walls under the siding? 

• What causes cracks in the walls and floors of a house?

• How can I tell if the exterior walls of a house are concrete block (CBS) or wood or brick?

• What are the common problems of different types of house foundations? 

• What are the warning signs of a dangerous deck?

• How can I tell whether my house foundation problems are caused by a sinkhole or expansive clay soil?

        Visit our EXTERIOR WALLS AND STRUCTURE page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.