What is a girder
In our quest to cover all the major framing members under the house, we have come to the girder.
In wooden framing, the girders are larger framing members that support the joists. Masonry piers, steel columns, or the foundation wall will support the girder. The girder should have a sill between it and any supporting masonry. The girders support the weight of the flooring or walls and transfer it to the ground using piers/columns. A girder is usually made of several boards or an engineered product for longer spans or heavier loads.
The girder works in conjunction with the band to support the floor or ceiling joists. The joists can connect girder to girder or girder to the band. The floor joists can sit on top of the girder or tie directly to the girder. In more modern construction, that connection will be made with a piece of metal called a joist hanger. In older homes that connection tends to happen using a ledger board.
A girder with the joists sitting on top of it is sometimes referred to as a drop sill or a sill beam. Girders themselves are often referred to as beams or girder beams. With so many things in framing fitting the description of a beam we like to use a more specific term for the girder.
Girders often seem to be one the first things damaged by termites or dry rot. This seems to be entierly an issue of proximity to the ground. We’ll talk more about these wood-destroying pests at a later date.