A PRIMER ON LOAD BEARING WALLS...
CAUTION IS THE OPERATIVE WORD!!
Before any modifications are made to a wall in your home, it is important to
have a basic understanding of how that change could affect its structural
integrity. Here is a brief but to the point essay on this heavy subject!
There are two types of walls in a home...
load bearing and non-load bearing. Or maybe three if you count "sort of
Homes are over engineered with good reason. Do you really need 2x4 wall studs
every 16" (center to center) to prevent your house from collapsing? Under
most circumstances, the honest answer is no. Then, why is this an accepted
construction standard? Why not 18"? Or 24"?
Engineers design structures to be able to handle loads and forces greater
than what they could ever be expected to handle under real world conditions.
Based on the current sizing of lumber, and modern construction practices,
16" was determined to be the right spacing between wall studs for
residential load conditions. (There are exceptions, of course, as varying
construction materials allow for different specifications.)
This "over engineering" allows you to put a large cabinet or waterbed in your
upstairs bedroom, or a grand piano in the living room, and not having to worry
about your home collapsing on you! This margin of safety, designed into
structures via enforcement of building codes, is something for which we should be
Even so, we can't think in terms of cutting wall studs willy-nilly! If we are
engaged in a project that requires cutting of wall studs, we must try to
understand something about how weight or the structure above a wall, or load, is
distributed. Only then can we proceed safely and with the confidence that comes
with being prepared!
How do you determine whether a wall is load-bearing?
In simple homes, looking at the construction design can be a clue. For
example, in the graphic left, you can see that the wall shown is holding up an
intersection of beams holding up the upper floor. This would be considered
a load bearing wall.
However, often even an experienced carpenter will scratch his head!
Analyzing the wall loads in large, complicated homes is much more difficult to understand
than a simple, two-story colonial.
When there have been renovations, this determination
can become nearly impossible because changing one wall can make another wall
What to do? Even building inspectors rely on the "when in
When in doubt, assume the wall is load bearing and act
It is easy to understand how renovations can cause weight to be transferred
onto formerly non-load bearing partition walls. For example, the addition of
exhaust fans and attic stairways often requires cutting of ceiling joists, which
can also transfer loads from the original walls... the main (center of the
house) beam and the outside wall, onto non-load bearing walls that are in
between them. Adding a room in an attic can change the entire load bearing
status of the walls below.
To confuse matters further, some types of construction, such as post and beam
or steel girder, may not have any bearing walls at all except for the outside
walls. What's a mother to do??
Look at the structure of the house and ask the following questions:
- Is there a significant load above, such a built-up (multi-board) carrying
beam or another wall? Is there a full floor above it, or just an empty
- If you can view the joists in the attic, is the wall parallel or
perpendicular to them? Generally, load bearing walls are perpendicular to
the joists they support. If two separate floor joists or ceiling joists
intersect over a wall, that wall should be considered load bearing.
- Is it an outside wall? You should consider all outside walls load bearing.
If the house has been remodeled, a former outside wall could now be an
inside wall. Examine the foundation to find these "stealth"
- Look at the beams and posts in the basement. In multi-floor dwellings,
posts and beams in the basement indicate bearing walls above them, even up
two floors. Be aware that these multi-floor bearing walls may not be directly
above each other.
- In complex, large homes, the basement can be a jungle of carrying beams
and posts, crisscrossed and interlocked. Careful inspection is necessary to
determine how this maze of beams supports the house, and its effect on the
If you have any doubts about the strength or
loading status of the wall, GET PROFESSIONAL ASSISTANCE! You may even be
able to get your local town building inspector to stop by and take a look