Which Way Do Rafters Run?

An important thing to know about joists is that they usually run in the same direction throughout a house. If the visible joists in a basement or attic run east to west, for example, you can be fairly certain the invisible joists under the bedroom floor also run east to west.

How do you know which way joists run?

In most homes, floor joists will run the shortest length across a room. For instance, if you have a room that is 12 feet by 24 feet, the joists are going to run across the 12-foot dimension. Besides taking up the flooring, one way to tell is to determine where squeaks are on the floor.

Do joists and trusses run same direction?

When building a house, it is actually quite the opposite and most floor joists and floor trusses are laid perpendicular to each other. ... If the joists and trusses are running in the same direction, this means that they will all be attached to the same wall, increasing the load that the wall is carrying.