Load-bearing walls look like other walls on the outside but have several distinctive features inside the drywall that differentiate them from other walls. The direction the wall runs, the type of wall header, and the wood framing used at the top of doorways are all features used to identify load-bearing walls.
Load-bearing walls run the same direction as the roof ridge. They also run perpendicular to the floor joists. Floor joists can easily be inspected in homes with a basement. Access to a crawl space is necessary in homes without a basement.
Load-bearing walls employ wall headers that are larger than usual, called doubled top plates. If drywall has been installed, it is necessary to remove a section of it to inspect the wall header. The wall header runs horizontally along the top of the wall. Doubled top plates give load-bearing walls more strength.
In walls that have doorways, the drywall can be removed above the door to find load-bearing walls. In load-bearing walls, doubled 2-inch-thick lumber is used with a strip of plywood between the two layers. This compensates for the loss of strength from missing studs.
All exterior walls of a home are load-bearing. Most homes generally have at least one interior load-bearing wall, and larger homes have more.