How to Identify a Bearing Wall (Part 2)

Tricky Bearing Walls

Fig. A shows a typical bearing wall situation: A single bearing wall runs down the center of the house and joists run across it. Most bearing walls follow this pattern, but many don’t.

The kitchen/dining room wall in Fig. B, for example, runs parallel to the joists both above and below it, so you might assume it’s not a bearing wall. But notice that the attic joists run the other direction, across the second-floor wall. Those joists are supported by the second-floor wall, which is supported by the first-floor wall directly below it. So the kitchen/ dining room wall turns out to be a bearing wall after all.

The house in Fig. C has joists running two directions. The back part of the house follows the typical scenario, with the main bearing wall running down the center. But then–in order to create a big, unobstructed living room across the front of the house–the wall stops and the joists change direction. Because the joists must be supported on both ends, the living room/dining room wall is a bearing wall.

When There Are No Sure Signs

Some homes are built in such a way that you can’t see any sure signs. If your house was built on a concrete slab (no basement or crawlspace), you obviously can’t look under the walls for extra support.

At the same time, attic trusses can eliminate sure signs above walls. (Trusses are those one-piece, factory-built rafter assemblies held together by metal plates. If your home was built within the past 30 years, you likely have them.) Most trusses don’t require mid-span support, so a typical one-story house with trusses won’t have any bearing walls. But you can’t assume this.

Because they rarely end or overlap above interior walls, trusses aren’t very helpful in identifying bearing walls. In your attic, you might be able to see markings on the trusses saying something like “bearing point,” meaning that the truss must have a wall or beam under it there. But not all trusses are marked, so just because you don’t see a label, doesn’t mean the truss is unsupported.

In cases like these, where you can’t find sure signs, it’s best to get professional advice. Begin with a call to your local building inspector (in the local government section of your phone book). It’s not the inspector’s job to help you plan projects, but many are willing to provide help like this. If not, you can hire a contractor to visit your house.

This is a new and improved version of a previously run article in The Family Handyman.

Two Traps to Watch Out for …

Distinguishing a bearing wall from a partition wall is usually a straightforward job. But houses, especially old houses, are full of surprises and it’s easy to get fooled.

Here are two situations I’ve seen again and again:

Basement Beams Removed

On one of my first wall-removal projects, I surveyed the basement, saw no beefed-up support below the wall and grabbed my sledgehammer. But as I knocked the plaster off the wall, I noticed a large header across the top of the doorway. Made from two 2 x 6s, it was much stronger than necessary-unless the wall was a bearing wall.

So I made a closer inspection of the basement. After removing a few suspended ceiling panels, I could see bent, leftover nails and nail holes in the joists below the wall. I pulled a rug back and saw the outline of a post footing in the concrete floor. It was clear that someone had simply removed a beam and posts. The wall above was a bearing wall after all. And thinking it was a partition wall, I nearly knocked it out without providing temporary support.

Partition Walls Become Bearing Walls

I consider all the wails in my old house bearing walls–not because they were originally intended to support weight, but because my joists are too small. The undersized joists flex and sag, putting downward pressure on all the walls. So if I were to remove any wall in my house, I’d have to treat it like a bearing wall. Otherwise, the ceiling above the wall would probably drop a fraction of an inch and eventually sag a lot.

You can tell whether your partition walls are playing a weight-bearing role by looking at your ceilings. If they’re sagging, you should probably treat them as bearing walls. Even if a ceiling is sagging badly, it’s often hard to tell just by looking up at the ceiling. So use a ladder to get your head right up against the ceiling and look across the ceiling just as you’d look down a board to see if it’s straight.

How to Identify a Bearing Wall (Part 1)

Advice on what to be on the look out for when removing a wall is offered. The important question is whether the wall is a bearing wall or a partition wall. A bearing wall helps to carry the house, whereas a partition wall simply divides two rooms. Removing a bearing wall is more complicated that removing a partition wall.

Back when I was a contractor, I got a lot of calls from homeowners who wanted walls removed–walls between the kitchen and dining room were the most common targets. We would discuss the project for a minute or two, then they’d ask for a “ballpark” estimate. “Somewhere between $500 and $10,000” was always my ballpark answer.

I wasn’t trying to be a wiseguy. Tearing out a wall can be a small, simple, filthy job, or a big, complex, filthy job. And it’s impossible to know which until you answer two questions: (1) Is it a bearing wall? and (2) What’s inside the wall?

This article will focus on the first question: whether a wall is a bearing wall or a partition wall. A partition wall simply divides one room from the next. A bearing wall also divides rooms but has a second, more critical, role: It holds up part of your house.

NOTE: We’re using “bearing wall” here to describe interior walls. Exterior walls almost always carry weight.

Removing a bearing wall is a lot more work than removing a partition wall. With a bearing wall, you have to provide temporary support to the joists above. Then, after you’ve knocked out the wall, you have to install a strong beam to support the joists permanently.


Bearing walls have a simple job: to transfer weight from above down to the foundation below. The weight above may be the roof, a floor or a ceiling.

The roof is usually supported only by the exterior walls, which also support joists at one end. So in a typical house, bearing walls support only joists: floor joists if there’s a floor above; or attic joists if there’s an attic above.


Just looking at a wall won’t tell you whether it’s a bearing wall or a partition wall. Covered with plaster or drywall, they look exactly the same.

Often, you can spot a bearing wall based on its orientation within a house. A bearing wall usually runs perpendicular to the joists and runs very near the center of the house. In a two-story house, you’ll find the second-floor bearing wall “stacked” over the first-floor bearing wall.

But rules of thumb like these all have exceptions, so always look for sure signs of a bearing wall. Sure signs are visible only from the attic above or the basement or crawlspace below your house. Never ever knock out a wall without looking for sure signs first.

Sure Sign No. 1: Extra support directly below the wall

If your house is built over a basement or crawlspace, look for a beam (Fig. A), doubled joist (Fig. B) or stud wall beneath the first floor. Beams or doubled joists are supported by posts that rest on footings. Extra supports like these tell you that there’s a bearing wall directly above; no extra support means no bearing wall.

Sure Sign No. 2: Joists that end over a wall

Joists have to be supported on both ends. So crawl up into your attic and look for joists that overlap (Fig. A) or end over a wall (Fig. C). In either case, the wall below is definitely a bearing wall.

A trip to the attic is helpful even if you’re wondering about a first-floor wall in a two-story house. If you find a bearing wall on the second floor, you can be sure that the first-floor wall below is also a bearing wall.

But remember this: The lack of overlapping joists doesn’t mean that the wall below isn’t a bearing wall. The attic joists in Fig. B, for example, are long enough to span from one side of the house to the other (no overlap in the middle). But they still need support in the middle, so the wall under them is a bearing wall.

Connect Wire Right

Done right, electrical connections will provide safe, trouble-free service forever. Done wrong, they can loosen as wires expand and contract with changes in temperature. At best, these loose connections are annoying: They interrupt power to lights or outlets and can cost you hours of troubleshooting. At worst, they can overheat and burn down your house.

Making good connections doesn’t take any more time or effort than making bad ones. But it does take know-how …

Stripping Wire

The first step in connecting any wire is to remove insulation. The cable used to wire most homes has two layers of plastic: You have to slit and cut away the sheath that contains the bundle of wires. Then you strip off the insulation that covers individual wires.

For slicing the sheath, use the cheap and simple “cable ripper” (less than $2 at home centers and hardware stores). The ripper’s tooth is dull enough so it cuts sheathing without damaging wire insulation. But to make that dull tooth cut, you have to squeeze and pull hard.

The best tool for stripping the insulation is a wire stripper ($4 to $12). There are a few types available, but I like the one shown here because it works well for other wiring tasks too. Strippers have several pairs of notches marked according to the wire size or “gauge” they’re intended for. (Remember, the smaller the number, the thicker the wire.)

People often use utility or pocket, knives for both slicing the sheath and stripping the wire. But a knife is hard to control; it’s easy to slice into insulation when cutting a sheath, or damage the wire when you’re stripping insulation.

Twist-on Connectors

Wire connectors, usually referred to by the brand name Wire-Nut, come in several color-coded sizes. You can tackle just about any household wiring job with the yellow and red sizes. Connector packages list the connectors’ capacities. You can connect up to three 14-gauge wires with a yellow connector, for example, but if you want to connect four 14-gauge wires, you’ll need the larger red connector.

A pack of 50 connectors sells for about $3. Make sure the ones you buy are UL-listed. There’s not much difference between one brand of connector and the next, but you’ll find that connectors with wings are easier to grip and twist on.

Screw Terminals

The screw terminals found on light switches and outlets are nearly foolproof. Just be sure to hook the wire around the screw clockwise; if you run the wire counterclockwise, the hook will open as you tighten the screw. To prevent contact with the bare ground wire inside the electrical box, it’s a good idea to cover the screws by wrapping electrical tape around the body of the switch or outlet a couple of times.

NOTE: “Stranded” wire, which consists of dozens of tiny wires, is slightly thicker than solid wire of the same gauge. To avoid cutting into stranded wire, jump up one notch on the stripper. (To strip 18-gauge stranded wire, for example, use the 16-gauge notch.)

WARNING: Many outlets and switches have screw terminals and holes in the back. These “stab-in” holes make for quick, easy connections: You just push the wire into the hole. But since they don’t lock firmly onto the wire the way screw terminals do, stab-ins can be unreliable, even dangerous. So always use the screw terminals.

  1. CUT a slit in the cable’s plastic sheath with a cable ripper. Just place the ripper about 10 in. from the end of the cable, squeeze the jaws together and pull hard; the tooth inside the ripper slices the sheath.
  2. PULL the cable’s sheath and paper insulation to one side and cut them off. You can use wire strippers, wire cutters or a knife to cut away the sheath–just be sure not to damage the plastic insulation on the individual wires.
  3. STRIP about 5/8 in. of insulation off the end of each wire. Be sure to match the gauge of the wire (it’s stamped on the cable’s sheath) with the right pair of notches; if you use a smaller pair, you’ll damage the wire.
  4. HOLD the wires tightly with the ends even and insert them into the connector. If you’re connecting more than two wires, hold them in a tight bundle, not all side by side. You don’t have to twist the wires together before inserting them.
  5. TWIST the connector clockwise until you’ve screwed the wires as far into the connector as they can go (you’ll feel them hit a dead end). Then give the connector a few more turns to twist the wires together outside the connector.
  6. Connecting stranded wire to solid wire

If you’ve ever installed a light fixture, you’ve probably experienced this: You hold the stranded wire coming from the fixture against the solid wire coming out of the wall or ceiling and twist on the connector. But something doesn’t feel right. So you give the wires a gentle tug and–just as you suspected–the stranded wire pulls right out of the connector.

This happens for two reasons: First, the stranded wire, made up of tiny individual wires, is flexible and gets pushed out of place as you twist the connector. Second, most of the connectors that come with light fixtures have soft plastic threads; they just don’t bite into the wire like the metal-threaded connectors that you buy separately.

Here’s how to make the connection work:

  1. Twist the tiny wires of the stranded wire tightly together.
  2. Toss the light-manufacturer’s connectors in the trash.
  3. Hold the wires so that the tip of the stranded wire is about 1/8 in. beyond the tip of the solid wire.
  4. Twist on a yellow connector.
  5. BEND the exposed wire into a U-shaped hook using wire strippers or needle-nose pliers. Then loop the wire over the screw so that it runs clockwise around the screw.
  6. PINCH the hook tightly around the screw. The hook doesn’t have to completely encircle the screw, but it must run at least two-thirds of the way around.

Before you remove a wall (Part 2)


The only way to know for certain what’s inside a wall is to remove the drywall or plaster. But most things are obvious if you know where to look, and you can make a good guess about the others with some careful thought and investigation:

  • First, take a quick stroll through your house and make a mental note of the location of light fixtures and outlets, sinks and toilets, hot water radiators or hot air registers. If you’re familiar with the general plumbing, heating and electrical layout of your house, you can make better predictions about what might be inside any given wall.
  • An unfinished basement or crawlspace is an information gold mine. From there, you can see all the cobweb-covered pipes, wires and ducts that enter a first-floor wall from below.
  • Attics are revealing too. It’s easy to see where plumbing vent pipes exit walls. Pull back insulation and you’ll find electrical lines. And in some houses, ductwork runs through the attic.
  • Plumbing lines make noise. If you think there might be plumbing inside a wall, turn on a tap, fill and drain a sink, or flush a toilet. Hold a cup to the wall and listen.
  • By removing the grille, you can look inside a duct to see which way it runs. If the duct takes a turn near the opening, you can use a flashlight and a small hand mirror to see around corners.
  • A small mirror can let you see inside a wall, too–if you’re willing to make a small hole in the wall. Cut a hole just large enough for the mirror and a small flashlight and you’ll see everything that’s between two studs.

AIR DUCTS are the biggest lines in walss. They’re also the most predictable because they almost always run straight and vertically. (Horizontal runs are made in attics, basements or between ceiling joists.) Some ducts are made from fiberglass, but the vast majority are metal.

There are two kinds of heating/air conditioning lines: delivery ducts and cold-air returns, which carry cool air back to the furnace. Delivery ducts in walls are usually made of sheet metal, are usually rectangular and fit between studs. Return lines often run through walls with no ductwork at all: A cavity between two studs simply serves as a duct. The only sign that a stud cavity serves as a return is a grille that allows for airflow.

Exhaust ducts (for dryers, and for bath and cooking fans) are smaller than heat ducts. Because they’re usually too large to fit in walls, however, they typically run through ceilings.

TRIMMERS are the shorter studs nailed to “king studs” on both sides of a door or window opening. Trimmers support headers in bearing walls. But just like headers, they’re found in non-bearing walls too, because they make nailing on trim easier.

HEADERS are the horizontal beams above doors and windows. in a bearing wall, headers have to be strong enough to support the weight of the roof or floors above. The size of these structural headers depends on the length they span. Above a narrow doorway, you might find a header made from two 2x4s. Above a wide window, you’ll probably find doubled 2x8s or 2x10s.

There’s no structural need for a strong header in a non-bearing wall. However, builders usually install a double 2×4 header anyway, because it provides backing for nailing on door trim.

GAS LINES run to gas furnaces, water heaters, stoves and dryers. They’re typically made from black metal pipe with threaded ends. Silvery galvanized pipe and flexible copper tubing also sometimes carry gas.

STUDS are spaced 16 in. or 24 in, “on center.” That means the centers of the studs are 16 or 24 in. apart; the spaces between the studs will measure 14-1/2 or 22-1/2 in.

BOTTOM PLATES are simply 2x4s or 2x6s that form the base of any stud wall.

PHONE LINES and other small wires–for cable TV, stereo speakers or intercom systems–snake their way through walls much like electrical lines. But because they can’t electrocute you, they’re not always buried deep within walls. You might find them hidden behind baseboards, for example.

TOP PLATES are doubled 2x4s or 2x6s that top off stud walls.

PLUMBING LINES come as a threesome: hot and cold water supply lines that are less than 1 in. in diameter, and a DWV (drain, waste and vent) line that can be up to 4-1/2 in. in outside diameter. The supply lines almost always travel as a pair, but the DWV line may or may not travel with them. DWV lines are large and drain by gravity, so they usually travel vertically through walls; any horizontal runs aren’t likely to be more than a few feet long. And don’t forget that DWV lines run up as well as down. If you cut into a second-floor wall, for example, you might find a “vent” line coming from the kitchen or bath below.

Because supply lines are and can work regardless of gravity, they can run horizontally through studs as well as up along them. The supply lines for a half bath, for example, might extend horizontally from the lines that serve the kitchen, while the DWV line runs straight down to a basement or crawlspace below.

If your home has hot-water you may also find pairs of heating pipes running through walls, usually vertically

ELECTRICAL LINES can run diagonally through a wall, but that’s rare. Instead, they usually follow vertical or horizontal paths. Horizontal lines run through holes in studs, usually a few inches above the outlets in the wall. To get around doorways, horizontal lines take a vertical turn so they can run up and over the header. But sometimes, lines pass over doorways through the attic, or under doorways through a basement or crawlspace. Vertical lines may run only partway up the stud or from the bottom plate all the way up through the top plate.

Before you remove a wall (Part 1)

Determining whether a wall contains wires, pipes or ducts is an important preliminary step in wall removal. Becoming familiar with a house’s plumbing, heating and electrical layout is the best way to predict the interior of a given wall. Tips on rerouting wires, pipes and ducts are included.

You have to know two things before tearing out a wall: First, you need to know whether it’s a bearing wall, and second, what’s inside it. In the April ’99 a House Works,” we explained how to recognize a bearing wall. This month, we’ll help you determine whether electrical, plumbing or heating lines are likely to complicate your wall-removal project. And since these lines follow paths determined by the wall’s framing, we’ll also outline the basic structure of a typical wall.

With most wall-removal projects, tearing out the wall is the simple part–you just rip off the plaster or drywall and knock out the studs. What can make the job time-consuming, complex and expensive are the wires, pipes and ducts inside the wall. Rerouting these lines often means cutting into other walls, messing up other parts of the house and hiring professional help.


  • Predicting the position of studs, headers and the other parts that form a wall’s skeleton is fairly easy. Framing practices are pretty standard across North America and haven’t changed much over the past half-century. Most stud walls closely resemble the one shown on pp. 96 and 97.
  • Interior walls are almost always made from 2x4s, usually centered 16 in. apart. The exception to this rule is bathrooms, where one wall (the one the toilet sits against) is likely to be 2×6 so it’s thick enough to contain the large waste pipe.
  • Most exterior walls also were made from 2x4s until the late 1970s, when some builders began using 2x6s so walls could hold thicker insulation. The studs in a 2×6 exterior wall are likely to be centered 24 in. apart.


It’s easier to predict the framing of a wall than it is to know what runs through it. The lines running through walls are less predictable than the wall’s framing. The walls near kitchens and bathrooms usually contain the most lines. The walls of a living room or bedroom in a one-story house may be nearly empty, except for electrical lines. But in a two-story house, those walls might contain plumbing and heating lines that serve the upper floor. Exterior walls, especially in cold climates, aren’t likely to hold anything but electrical, phone or cable TV lines and insulation.

Because they’re small and flexible, wires follow the least predictable paths within walls. Electricians and phone or cable TV installers can freely bend the wire around lots of corners, so they usually take the route that requires the least drilling through framing. As a result, wiring might take a dozen twists and turns as it runs through a wall.

Pipes that supply water or gas can also follow winding paths. But running pipe around corners takes extra work, so although supply pipes can zigzag through walls, they usually take a fairly direct route. Pipes that carry waste water are more direct, since they’re larger and depend on gravity. A waste pipe with a lot of turns would be likely to clog.

Heating ducts are so big that turning corners often means cutting away entire sections of a wall’s framing. So they usually go straight through walls.


Rerouting wires, pipes and ducts always takes some know-how and usually means tearing into other walls. Electrical lines are generally the easiest to reroute. When a wall is removed, it leaves a gap in the ceiling. And often, that gap lets you reroute wires through the ceiling without cutting into other walls. Remember, you can’t just splice wires together and bury the splices behind drywall; they must be contained in a junction box that has an accessible junction box cover. Plumbing lines and ducts are more troublesome. Electrical lines can zigzag through walls and slip through little holes, but pipes and ducts require straighter paths, more cutting and, often, professional know-how. If you think you might need help rerouting any type of line, get a professional estimate before you tear into the wall.