Floor Joist reinforcement
Marc Golightly
hole in a 2x10 floor joist for a soil pipe (ie 2x4 above and
below the hole for how long?, or what?)?
David Marchand
2X4 on edge on top and especially on the bottom (which is in tension on a
floor joist) about 2' long. The idea is to strengthen the stress carrying
capability of the wood at the top (in compression, but the subflooring will
add a lot of stress loading capability) and the bottom (in tension).
Fred S
Make your holes as close to the center of the floor joist as possible.
In a joist the top edge is in compression, the bottom is is tension.
In theory, there is neither tension or compression along the vertical
center-line of a simple beam .... ever see open web trusses
... the load carrying capacity is in the top and bottom chords.
Make round holes, no larger than required, as close to the center line
as possible. If possible keep the holes in the outer third of the
joist. If you feel like it, nail and glue a 2 x 4 to each side of the
joist below the holes, 4' total length should be more than enough
.... assuming your floor joists are not over spanned to start with.
John Talucci
>hole in a 2x10 floor joist for a soil pipe (ie 2x4 above and
>below the hole for how long?, or what?)?
I would suggest strapping an additional 2x10 to the area you plan to
drill or cut through. The length should be at least 5 feet in either
direction. Fasten the 2x10 to the beam first, then cut through. Be
careful not to cut a hole to close to the bottom of the joist. It might
cause it to crack.
bay...@kali.nas.com
>Does anyone know what type of reinforcing I need to cut a 4 inch
>hole in a 2x10 floor joist for a soil pipe (ie 2x4 above and
>below the hole for how long?, or what?)?
Acording to local code maximum hole size for a 2x10 would be 3" and it
would have to be no closer than 2" to either the top or bottom edge.
I don't know the layout so its hard to say what you can do. I had to
run a 4" hole trough 3 2x10s but it was in a place where the span was
3' between loadbearings (where a 2x4 would adequate). An option may be
to cut a peice of that joist completly away and make a box by running
headers (peices of 2x10) between the joist on either side (which
become trimmers) of the one you cut nailing them to the trimmers and
the cut ends of your joists. Two things. I prefer joist hangers to
nails and would prefer to do this if it happened near a bearing
point/wall. A lot depends on you loadbearing situation. This also
applies to the posibility drilling that 4" hole anyway and scabing on
a couple of 2x4s to the bottom where the #'s might work. Talk to your
local buildings and codes people they should be able to help you out.
--
Dave
Franklin Gingrich
<mgol...@path.som.sunysb.edu> writes:
>
>Does anyone know what type of reinforcing I need to cut a 4 inch
>hole in a 2x10 floor joist for a soil pipe (ie 2x4 above and
>below the hole for how long?, or what?)?
>
make a heck of a lot of difference except not cut the hole, or add a
supporting column under it. Scabbing on a couple pieces of 2x4 isn't
much use. If you were to sandwich the joist in full-length 2x4 top and
bottom, through-bolted with 1/2" bolts 16" oc on top and 32" oc on
bottom, maybe it would help.
But then, if you have a 9-1/2" 2x10 and apply 3-1/2" 2x4 top & bottom,
there's only 2" clear in between --- how are you gonna get a 4"+ hole
in that? So, in effect, you'd be bracing the joist with 2x2.
Either don't do it or acknowledge in advance that you will be
effectively destroying the joist. If you only cut one you may get away
with it. Of course, then again, you may not.
Good luck.
Frank
TwoJean Consulting
>
> In article <4kbgea$7...@abel.cc.sunysb.edu>,
> Marc Golightly <mgol...@path.som.sunysb.edu> wrote:
> >hole in a 2x10 floor joist for a soil pipe (ie 2x4 above and
> >below the hole for how long?, or what?)?
> >
>
> In a joist the top edge is in compression, the bottom is is tension.
> In theory, there is neither tension or compression along the vertical
> center-line of a simple beam .... ever see open web trusses
> ... the load carrying capacity is in the top and bottom chords.
>
> Make round holes, no larger than required, as close to the center line
> as possible. If possible keep the holes in the outer third of the
> joist. If you feel like it, nail and glue a 2 x 4 to each side of the
> joist below the holes, 4' total length should be more than enough
thicker, three to four feet long, bolted into the bottom for insurance.
Few others do this, though, but I don't like callbacks.
Dan Wensley
> Does anyone know what type of reinforcing I need to cut a 4 inch
> hole in a 2x10 floor joist for a soil pipe (ie 2x4 above and
> below the hole for how long?, or what?)?
It says you can reinforce a hole up to 6" on a 2x10
Tekkie©
On Thu, 8 Oct 2020 16:55:22 -0700 (PDT), Dan Wensley posted for all of us to
digest...
--
Tekkie