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In the process of converting underutilized space into living quarters, you often have to deal with some major roadblocks — walls, beams, and other supporting structures. Before you take a sledgehammer to that nuisance of a wall, realize that it can store many surprises — electrical wiring, plumbing, and ductwork. In addition, that wall may be supporting the second story or the roof. Knock out that wall, and the whole house may cave in . . . with you in it.
 | Before tearing out a wall, strip the drywall or plaster off the studs to see what's behind it. If you find a costly surprise, and change your mind, you're out only the cost of hanging new drywall. If you knock out the wall with a sledgehammer, you may find yourself paying for new plumbing, new electrical lines, and new ductwork, as well. |
What is a load-bearing wall?
Load-bearing walls transfer the weight of whatever is above them — the upper floor or the roof — to the foundation. Houses have three types of load bearing walls:
- The outside walls of the house are always load-bearing walls, because they support the roof.
- In a house with a conventional roof frame, interior walls that run perpendicular to the rafters support the roof. A truss roof requires no support from interior walls; it rests entirely on the outside walls of the house.
- In a house with two or more stories, interior walls or beams that are perpendicular to an upper story's floor joists bear the load of the upper story.
 | You can remove a load-bearing wall, but never without replacing it with a support that's equal or stronger than what you're taking away. |
What difference do conventional and truss roof frames make?
A conventional roof frame consists of joists that span the distance between the front and back or side walls of a house and the rafters that support the roof. A house with a conventional roof frame typically has an attic and requires an interior load-bearing wall to support the attic joists.
Truss roof frames consist of a web of sticks (typically 2 x 4s) that support the roof without the added support of an interior wall. Truss roof frames make removing interior walls much easier. The tradeoff is that truss roof frames provide little or no open space for an attic.
| To figure out the type of roof your house has, check the attic. You can usually access the attic from inside the house. Search the ceilings, especially in hallways, closets, and the attached garage, for a pull-down staircase or access door. You may also be able to sneak a peek through a cubbyhole in the upper floor. If you have plenty of open space in the attic, chances are good that a load-bearing wall on the floor below is supporting the joists. |
| If you have a conventional roof with a lot of open space in the attic that you don't want to convert into a room, consider using it to beef up the storage space. Add a pull-down staircase, lay sheets of plywood over the joists to create a floor, and add a couple of light sockets and a switch for turning the lights on and off. |
Is this wall load-bearing?
You can't tell whether a wall is load-bearing just by looking at it. You need to know what's above the wall and what's below it:
- If the house has a basement, go downstairs and find out what's below the wall. If the wall above has a wall or beam below it, the wall above is probably the load-bearing variety.
- If the wall is below an attic, go to the attic and determine whether its floor joists are running perpendicular to the wall below. If they are, the wall is supporting the attic floor.
- If the floor joists are hidden by a floor above or a ceiling below, you may need to chip away some of the ceiling to determine whether the joists run perpendicular to the wall.
 | Don't assume that all the floor joists upstairs run in the same direction. You may have a situation in which two walls that meet at right angles are both supporting walls! |
| You can really open up the interior of a house by removing unnecessary walls, but the supporting structure of the house is nothing that a weekend do-it-yourselfer should mess with. If you decide to remove a load-bearing wall, an engineer can recommend options for replacing the wall with another structure that provides equal or superior support. And always obtain a building permit from your town's building inspector and ensure that your planned changes comply with building codes in your area. |
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