Safe to drill hold in Wall Stud?
Foo-San Chan
Is it safe to drill 1.5-2 inch holes in the stud (2x4) of a load bearing wall.
The holes are for running a washing machine drain pipe. Currently there
are wall cabinets hanging there. I might have to run the pipe through a
couple of studs. The house is on a slab so I can't run them anywhere else
without making them visible. If unsafe, will adding another 2x4 to double
the studs be acceptable ?
Thanks,
Foo-San
Doug Miller
fc...@cps.udayton.edu (Foo-San Chan) wrote:
+Is it safe to drill 1.5-2 inch holes in the stud (2x4) of a load bearing wall.
No. This will weaken the studs too much.
+The holes are for running a washing machine drain pipe. Currently there
+are wall cabinets hanging there. I might have to run the pipe through a
+couple of studs. The house is on a slab so I can't run them anywhere else
+without making them visible. If unsafe, will adding another 2x4 to double
+the studs be acceptable ?
No.
+
+Thanks,
+Foo-San
----------
Doug Miller
dlmiller'at'inetdirect'dot'net
Casey
Foo-San,
I have often seen heating and plumbing contractors make holes as you
described. They install a special piece of steel angle to bridge over the
weakened areas. Ask about it at plumbing supply houses. It just gets bolted
screwed or nailed on.
An alternative would be sandwiching the stud with 3 1/2 inch wide strips of
plywood glued and screwed to both sides.
Another alternative is to frame in a header of double 2x12 above the area
"undermined" by the drilling, making that space non-load-bearing.
The easiest alternative is to frame this wall in 2x6 instead.
Some ideas.
Casey
Foo-San Chan <fc...@cps.udayton.edu> wrote in article
<5gkg2a$1...@news.cps.udayton.edu>...
> Is it safe to drill 1.5-2 inch holes in the stud (2x4) of a load bearing
wall.
> The holes are for running a washing machine drain pipe. Currently there
> are wall cabinets hanging there. I might have to run the pipe through a
> couple of studs. The house is on a slab so I can't run them anywhere
else
> without making them visible. If unsafe, will adding another 2x4 to
double
George Jefferson
:+Is it safe to drill 1.5-2 inch holes in the stud (2x4) of a load bearing wall.
:
:No. This will weaken the studs too much.
:
:If unsafe, will adding another 2x4 to double
:+the studs be acceptable ?
:
:No.
can you elaborate? You are removing about half the material, so doubling
the stud should make up for it. It makes a big difference if you
are drilling 1.5 or 2"..it also makes a difference (it seems) if
you are talking about 1 or 2 studs, or are you going the whole
length of the wall..
Casey
Foo-San,
I have often seen heating and plumbing contractors make holes as you
described. They install a special piece of steel angle to bridge over the
weakened areas. Ask about it at plumbing supply houses. It just gets bolted
screwed or nailed on.
An alternative would be sandwiching the stud with 3 1/2 inch wide strips of
plywood glued and screwed to both sides.
Another alternative is to frame in a header of double 2x12 above the area
"undermined" by the drilling, making that space non-load-bearing.
The easiest alternative is to frame this wall in 2x6 instead.
Some ideas.
Casey
Foo-San Chan <fc...@cps.udayton.edu> wrote in article
<5gkg2a$1...@news.cps.udayton.edu>...
> Is it safe to drill 1.5-2 inch holes in the stud (2x4) of a load bearing
wall.
> The holes are for running a washing machine drain pipe. Currently there
> are wall cabinets hanging there. I might have to run the pipe through a
> couple of studs. The house is on a slab so I can't run them anywhere
else
> without making them visible. If unsafe, will adding another 2x4 to
double
eugene kulinek
On the similar note: in the new houses they drill tousands of holes in
joists, etc. which I do not like. The holes look very unprofessionally (to
a carpenter at least). These holes supposed to be in the middle of the
width but they never are.
My preference is to lay cables under the joists and install hanging
ceiling, but some builders tell me it is not possible because of the
electic code (I will have to check this as I am getting different answers).
The only code that deal with holes is electrical and they do not worry
about load bearing.
George Jefferson <geo...@mech.seas.upenn.edu> wrote in article
<5gpdef$m...@netnews.upenn.edu>...
> :+Is it safe to drill 1.5-2 inch holes in the stud (2x4) of a load
bearing wall.
Peter Bucy
>
>On the similar note: in the new houses they drill tousands of holes in
>joists, etc. which I do not like. The holes look very unprofessionally (to
>a carpenter at least). These holes supposed to be in the middle of the
>width but they never are.
>
>My preference is to lay cables under the joists and install hanging
>ceiling, but some builders tell me it is not possible because of the
>electic code (I will have to check this as I am getting different answers).
>The only code that deal with holes is electrical and they do not worry
>about load bearing.
Generally, drilling holes in joists for electrical conductors is not
a serious matter. Building code and good practice will keep you out of
trouble in most situations. The majority of problems arise when the
home was not designed for plumbing drain lines and HVAC duct work.
Actually, I prefer floor trusses and wood-I's. Both are engineered
to allow mechanical systems to pass through them without any
structural risk. Of the two, floor trusses are my choice.
Peter A. Bucy - Home Builder
email pe...@ix.netcom.co
homepage http://www.netcom.com/~petex
Richard F. Gillette
George Jefferson wrote:
>
> :+Is it safe to drill 1.5-2 inch holes in the stud (2x4) of a load bearing wall.
> :
> :No. This will weaken the studs too much.
> :
> :If unsafe, will adding another 2x4 to double
> :+the studs be acceptable ?
> :
> :No.
>
> can you elaborate? You are removing about half the material, so doubling
> the stud should make up for it. It makes a big difference if you
> are drilling 1.5 or 2"..it also makes a difference (it seems) if
> you are talking about 1 or 2 studs, or are you going the whole
> length of the wall..
the diameter of the hole is no greater than 40% of the stud width, and
no closer than 5/8" to the edge, also no notch or cut in section, if you
double the studs you can go to 60%, but only for 2 successive studs.
--
Richard F. Gillette PE, W9PE, Board Member, Harper CC \\////
RF gillette inc. PO Box 1605, Palatine, IL 60078-1605 ( oo )
r.f.gi...@ieee.org, v)847-526-2626, f)847-526-2944 ooOO=={}==OOoo=
Doug Miller
geo...@mech.seas.upenn.edu ( George Jefferson ) wrote:
+:+Is it safe to drill 1.5-2 inch holes in the stud (2x4) of a load bearing wall.
+:
+:No. This will weaken the studs too much.
+:
+:If unsafe, will adding another 2x4 to double
+:+the studs be acceptable ?
+:
+:No.
+
+can you elaborate? You are removing about half the material, so doubling
+the stud should make up for it.
No, this is wrong. The strength of a structural member is proportional
to the *square* of its dimension, so notching a stud to one-half its depth
reduces its strength by 75%, requiring that it be quadrupled, not doubled,
to achieve the original strength. Boring a 2-inch hole through the center of
a stud doesn't reduce the strength as much, but it's still a bad idea.
+ It makes a big difference if you
+are drilling 1.5 or 2"..
Yes, it does -- for the reason I cited above, that the strength is
proportional to the square of the thickness.
+it also makes a difference (it seems) if
+you are talking about 1 or 2 studs, or are you going the whole
+length of the wall..
+
Well, he said he was going to install a drain -- in most cases, I think
that would imply drilling through more than 1 or 2 studs.
Doug Miller
red...@tulsa.oklahoma.net (Kirk Kerekes) wrote:
+In article <5gve2r$l...@news.inetdirect.net>, dlmiller_at_inetdirect.net
+(Doug Miller) wrote:
+
+.. geo...@mech.seas.upenn.edu ( George Jefferson ) wrote:
+.. +:+Is it safe to drill 1.5-2 inch holes in the stud (2x4) of a load
+bearing wall.
+.. +:
+.. +:No. This will weaken the studs too much.
+.. +:
+.. +:If unsafe, will adding another 2x4 to double
+.. +:+the studs be acceptable ?
+.. +:
+.. +:No.
+.. +
+.. +can you elaborate? You are removing about half the material, so doubling
+.. +the stud should make up for it.
+..
+.. No, this is wrong. The strength of a structural member is proportional
+.. to the *square* of its dimension,
+
+Actually, I believe that it is proportional to the cross-sectional area,
Really?? This would imply that a wall built with the studs oriented so:
--- --- --- --- ---
is just as strong as one built with the studs oriented so:
| | | | |
After all, the cross-sectional areas are the same.
+which does _not_ imply that notching a stud to half-width requires
I didn't say "half-width" -- I said half its *depth* which is not the same.
+quadrupling it in order to match the strength. You might get different
+results if you specified _stiffness_ instead of strength, however.
+
The strength of a beam, column, joist, or whatever, is directly proportional
to its thickness (the direction *perpendicular* to the stress imposed on
it -- e.g. the '2' dimension of a 2x8 floor joist or a 2x4 wall stud) and to the
*square* of its depth (the direction *parallel to the stress imposed on it --
e.g. the '8' dimension of a 2x8 joist, or the '4' dimension of a 2x4 stud).
Thus -- assuming actual, not nominal, dimensions -- a 4x4 is twice as
strong as a 2x4, but a 2x8 is four times as strong, when oriented properly.
And if you notch out half the depth of a 2x4 wall stud, you have reduced
its strength to 1/4 of its previous value -- requiring that it be quadrupled
to achieve the original strength.
----------
Jeanne Petrangelo
Foo-San Chan (fc...@cps.udayton.edu) wrote:
: Is it safe to drill 1.5-2 inch holes in the stud (2x4) of a load bearing wall.
: The holes are for running a washing machine drain pipe.
Ignoring the debate about what sizes of holes are okay...
I saw this on a cable home show... don't laugh yet: it looked like a
good idea. They drilled a hole in a stud for a drain pipe, and before
putting up the drywall they fastened a metal plate on the wall side of the
stud, over the section with the drainpipe. The metal plate is to protect
the pipe in case anyone forgets and tries to drive a nail into the stud
(for hanging a picture or whatever).
Jeanne
Doug Miller
"Richard F. Gillette" <r.f.gi...@ieee.org> wrote:
+George Jefferson wrote:
+>
+> :+Is it safe to drill 1.5-2 inch holes in the stud (2x4) of a load bearing wall.
+> :
+> :No. This will weaken the studs too much.
+> :If unsafe, will adding another 2x4 to double
+> :No.
+>
+> can you elaborate? You are removing about half the material, so doubling
+> the stud should make up for it. It makes a big difference if you
+> are drilling 1.5 or 2"..it also makes a difference (it seems) if
+> you are talking about 1 or 2 studs, or are you going the whole
+> length of the wall..
+the diameter of the hole is no greater than 40% of the stud width, and
+no closer than 5/8" to the edge, also no notch or cut in section, if you
+double the studs you can go to 60%, but only for 2 successive studs.
+--
+Richard F. Gillette PE, W9PE, Board Member, Harper CC \\////
+RF gillette inc. PO Box 1605, Palatine, IL 60078-1605 ( oo )
+r.f.gi...@ieee.org, v)847-526-2626, f)847-526-2944 ooOO=={}==OOoo=
Thank you! I didn't have the reference handy...but now let's do some
figuring.
40% of 3.5" = 1.4" or slightly more than 1-3/8".
Obviously a hole for a 1-1/2" drain pipe is too large -- as I said.
George Jefferson
:No, this is wrong. The strength of a structural member is proportional
:to the *square* of its dimension
thats an interesting statement...the only way I can see the strength
related to the square of one side dimension (therefore the square
of the area) is if we think limit load is the buckling load.
which could well be..I just like to know the reasons
for rules of thumb...
If buckling is the concern then when you double the stud,
so long as you secure the two together well I'll still argue
that the pair with a 50% hole is better than an uncut single.
I wouldn't want to argue the point with a building inspector
though :-)
George Jefferson
:. +Actually, I believe that it is proportional to the cross-sectional area,
:.
:. Really?? This would imply that a wall built with the studs oriented so:
:. --- --- --- --- ---
:. is just as strong as one built with the studs oriented so:
:. | | | | |
:. After all, the cross-sectional areas are the same.
sure, but a real bitch to hang drywall.
:. The strength of a beam, column, joist, or whatever, is directly proportional
:. to its thickness (the direction *perpendicular* to the stress imposed on
:. it -- e.g. the '2' dimension of a 2x8 floor joist or a 2x4 wall stud)
on the right track, except how do you figure the stress on a wall stud
is perpendicular to the "2" direction?
I'll step out of this thread with the observation that the half
dozen vastly different but seemingly reasonable theories proposed
are a good example of why we have building codes...
Paul
Doug,
> Thus -- assuming actual, not nominal, dimensions -- a 4x4 is twice as
> strong as a 2x4, but a 2x8 is four times as strong, when oriented
properly.
> And if you notch out half the depth of a 2x4 wall stud, you have reduced
> its strength to 1/4 of its previous value -- requiring that it be
quadrupled
> to achieve the original strength.
There's a logical slip here. The 2x8 here is being stressed in its
transverse direction, as the live load on a floor beam: deflection. But the
2x4 in question is being loaded in its longitudinal direction, as with a
stud. In such a case, there is no deflection, but there might be
considerations of the load bearing capacity per unit area of the stud
material.
In other words, once the hole is made, is there enough material left at
that point of the stud to bear the weight above it?
The other consideration is the deflection of the stud. If the wall is hit,
or if weight is hung assymetrically on it, as with shelves, is the stud
strong enough at the point in question not to break? Here the analogy of
the I-beam applies. As long as the hole is centered in the width (4"
dimension), the compression/tension strength of the two opposing edges
should remain quite high. This of course depends on the size of the hole
relative to the size of the stud.
Paul
"Unless the Lord builds the house, the laborers labor in vain." Ps.127
Chris Lawson
dlmiller_at_inetdirect.net (Doug Miller) wrote:
>No, this is wrong. The strength of a structural member is proportional
>reduces its strength by 75%, requiring that it be quadrupled, not doubled,
>to achieve the original strength. Boring a 2-inch hole through the center of
>a stud doesn't reduce the strength as much, but it's still a bad idea.
Ok, time to throw in a dose of reality.
For compression along the axis of the board (ie a standing wall
member), the strength is proportional to the cross-sectional area.
Holes in the board simply reduce the strength proportional to the
reduction in cross section area. (This is not true if the board is in
tension, but wood is lousy in tension anyway)
For long lengths and thin boards in axial compression, buckling may be
a factor. The buckling point depends on the shape mostly.
For bending (horizontal beam supported at ends), the strength depends
again on the shape and cross sectional area. For retangular cross
sections it is proportional to the height^2 x width. For roof trusses
and floor joints doubling the height from a 2x4 to a 2x8 quadruples
the strength. (This ignores the extra weight of the beam and the fact
that a 2x4 isn't truly 4", etc).
Chris Lawson
law...@micron.net