Building Code for Posts on a Screened Porch

Building Code Basics

• State and county building codes usually make general requirements for large areas, while city codes contain information specific to a certain area. There are thousands of building codes in the United States, but there is some uniformity because most draw upon information provided by the International Code Council (ICC) and the International Building Code (IBC). The ICC creates and publishes building code guidelines, such as the IBC, for use throughout the world. You must obtain a copy of the local building code in your area to determine the exact requirements for screened-in porch posts.

Porch Posts

• Most requirements for support members for porches depend upon the size and weight of the individual porch. For example, building codes from Snohomish County, Washington and Chicago, Illinois, require a minimum post measurement of 4 inches by 4 inches for posts as tall as 8 feet. For taller posts, a minimum size of 6 inches by 6 inches is required. Nearly all other requirements for posts, such as distancing, attachment (brackets, plates, bolts, screws) and arrangement depend upon the porch.

Post Material

• Building codes may make stipulations about the type of material used in porch posts. The city of Longmont, Colorado, for instance, allows Redwood lumber in porch post construction only if the wood contains no knots or splits. Longmont requires pressure treated lumber if suitable Redwood is unavailable. In areas with high levels of moisture, such as coastal regions, building codes may stipulate certain types of moisture resistant wood for porch posts, or require the use of moisture resistant coating on wood.

Permits and Inspections

• Most building codes in the United States require an approved professional or public employee inspect building plans before a building permit is issued. The inspection process includes a look at your blue prints and, in some cases, an inspection of the building site. During the inspection process, a public official determines whether your posts meet requirements for spacing, height, thickness and all other relative measurements. Contact your local building department for rough guidelines on any requirements before you draft construction plans.