The issue was whether or not a suspected load-bearing wall could be removed on the first floor level. This is a question I get a lot, but the method for sorting out the load-bearing capacity of a particular studwall is far from straightforward. The short answer is that typically I figure out the load path of the structure from the roof and floor levels down to the foundation. Of course, the interior drywall or plaster covering all of the structural framing doesn’t make this easy on me! Many times, I rely on my prior knowledge of what that type of house looks like when it’s been gutted. Admittedly, I see older, pre-WW2 houses gutted more often than newer housing, and this was a 1970’s, two-story Colonial.
So what are some of the items I’m looking for? Good questions, here are the majority of them:
- Do all of the walls stack on top of each other? You would think they always do, but alas, many times this is not the case and they are offset from each other. This is something that will need to be corrected.
- Does the subject studwall have a single or double top track? This is the horizontal 2x4 at the top of the studwall that frames to the floor joists. Typically a non-load-bearing wall has a single stud track, while standard carpentry practice is that a double track is present for a load-bearing studwall. The theory behind the double top track is that the top track is always continuous, even where the stud tracks are spliced. Framing errors are common, so we can’t rely solely on this indication.
- Do the floor joists overlap at the wall? If the floor joists overlap, then the subject wall is definitely a bearing wall. If they do not overlap, it could still possibly be a load-bearing wall.
- Is the roof framing comprised of pre-engineered wood trusses or roof rafters? Trusses typically span between the exterior walls. The roof rafters typically need the ceiling joists for lateral bracing, and the subject wall may be supporting those ceiling joists.
So for this one, it turned out the subject wall was load-bearing, and the wall jogged along the central bearing support beam in the basement. The first floor joists were supporting portions of the load-bearing wall which extended up to the second floor joists. In this scenario, we provided design drawings to correct the framing errors during the initial construction. This happens every so often, but the more typical scenario is that the house is framed correctly. If the dwelling is in the City of Pittsburgh, you need structural drawings no matter what. If it’s outside of the city, usually only a letter stating that the wall is load-bearing and a header beam size is provided for straightforward header beams.
If you have a similar situation with whether a wall is load-bearing or not, or any other structural concern with their house or building, please give me a call at 412-770-7590 or email BobTheStructuralEngineer@gmail.com.