Floor joists are designed to carry the load above it. A notched floor joist means you are altering the structure for the home. That’s not to say you can’t do it though, but it must be done right.
When it comes to roof, floor & ceiling framing, it’s critical to know how much can be drilled out of it or notched out of it before compromising structure. Generally, holes should not be more than a ¼ the depth of the framing member and located not less than 2” from the edges. Notched floor joist must only be made at the top of framing members, with the maximum distance from the edge of the support not exceeding ½ the depth of the framing member and no deeper than a third of the depth of the framing member.
Of course, the floor joists themselves must be properly supported, for example, on foundation walls or by using metal joist hangers.
Unsure what might be going on with a notched floor joist in the home you are about to buy or the home you already own? Does the notched floor joist look like some of the handy work done by those in the pictures above? Protect yourself…get it inspected!