Holes in Wood Joists
Holes in Wood Joists
(OP)
I have a client who is wanting to drill a hole in his floor joist. I have some concerns about the hole that I need to back up with the code. The client wants to drill this hole 13" from the support of the joist. For some reason I can't seem to find the limitation as to how far from the support you are allowed to drill holes. The only thing I can find is where the code states that you can't drill a hole larger than D/3. Is there such a limit in the code?






RE: Holes in Wood Joists
RE: Holes in Wood Joists
1) Neither the IRC or IBC has a end distance requirement for joist holes placement.
2) If you designed the joist (or the joist could be designed) per the Conventional Light-Frame Construction Section 2308 of the IBC or the IRC, then you can use the D/3 hole size.
3) If you are designing it under the NDS then the allowable hole size of D/3 is not stated any where that I can find. When I design under the NDS I use the WWPA limitations on hole sizes and spacing per grade and size of the 2x to 4x joists/beams, for the general placement of the holes. Where I know the location of the hole and whether there are no other holes/knotholes within one to twice the depth of the member to it. Then if the reduced section calculations work I will go up to the D/3 size for the hole.
4) At bearing ends the hole should be a minimum the depth of the member away from the inside face of the bearing. If not, I then to look it the hole more like a notch. And hope that the joist/beam has low enough shear to get it to work. It has been more of a problem with beams rather then joists.
Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.
RE: Holes in Wood Joists
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: Holes in Wood Joists
You might be able to extrapolate this to other types of standard wood joists too, outside of TJI's and the like.
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com