If you are reading this, you are probably considering remodeling your home. Load-bearing walls always run perpendicular to the ceiling joists of your home. Ceiling joist can be easily identified as what your sheetrock is nailed to. Take a look up in your attic and see for yourself. Insulation will be between them. A joist rarely runs more than about 10 feet without extra support. The length depends on the type of joist. An exterior wall is always a load bearing wall. Do not attempt to compromise the structural integrity of these walls if you don’t know what you are doing. If your known bearing walls (exterior) are more than 10 feet apart (and they almost always are), there’s almost certainly a bearing wall in there somewhere, probably close to the center, unless the span is extremely long. Study the picture on the left and see how a load bearing wall works.
For most houses, you can just figure out which way the joists run, then look for the wall that runs halfway through. If there’s a gap in the wall, it won’t go all the way up to the ceiling, but instead come down a foot or so where the header is. The header or top plate is an extra-thick piece or pieces of wood (often 2x4s nailed together) that distribute the weight of the joist above and help support the roof. Don’t forget to check with your city government to see if you will need a building permit for this kind of work. If you live in San Antonio, the answer is YES, you need a building permit.
Cut up roofs often have complex joist patterns, and you can’t always assume that a bearing wall will run straight across the house. If you are fortunate to have a set of floor plans, study the roof plan and framing plan closely. This will give you a better idea of how the house was framed. Big open spaces will sometimes have support posts, or complex diagonal bracing. If you are a do it yourselfer and doing a home remodeling project yourself, it is worth money to hire an expert to tell you which walls are load bearing and which ones can be removed safely. Trust me, you don’t want your house to come crashing down because you removed a wall that was one of the main supports of the house.