Floor Joists

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A/A Fuel GTX

A/A Fuel GTX

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I'm pretty sure the NEC doesn't address this but maybe someone knows the answer to this question. When a structure uses the wooden " I Beam " type of floor joists, is there any limitation on what size hole can be bored through the joist? These are the type that are made out of particle board and have pre punched ko's every so often along the span.
 
You need to get this info direct from the manufacturer.

If you can get the name off the side of the beam you can than usually get that info from the companies web site.
 
Also check your building code. For example, Section R602.6 of the IRC covers the provisions for Drilling and Notching certain wood members.
 
Typically, the the middle third of the height, in the middle third of the span, is free. The closer you get to the bearing points, the more stringent the limitations on penetrations.
 
m73214 said:
I'm pretty sure the NEC doesn't address this but maybe someone knows the answer to this question. When a structure uses the wooden " I Beam " type of floor joists, is there any limitation on what size hole can be bored through the joist? These are the type that are made out of particle board and have pre punched ko's every so often along the span.
Click to expand...

If you need a different hole than the pre-punched KO's, you should seek guidance from the manufacturer.
 
Look around on the I-joists. There will be a packet with istallation instructions fastened to a few of the joists. Around here, the framers usually just leave them hanging there. The instructions will include a chart telling you where and what size hole you can bore.
 
I agree with all that's been said so far. Out here on the left coast we use a lot of these products; the most popular is the TJI (truss joist I-beam). With these you can cut out almost the entire web with no problems (just watch the plumber!!). It is always wise to check with the structural engineer or product manufacturer before you cut or drill. Also watch for the new engineered beams that look like OSB only thicker, they usually cannot be drilled or notched without engineering approval.

Bob on the left coast.
 
LarryFine said:
Typically, the the middle third of the height, in the middle third of the span, is free. The closer you get to the bearing points, the more stringent the limitations on penetrations.
Click to expand...

Larry is right. In the first third of the spans you can make an 1 1/4' hole. As you get to the center, you can take out more wood.

Ask the framing foreman for more info.
 
Yes. Hi Tom, Drilling Larger holes through "I" Joists are dependent upon the joist span, and web depth. Some times a larger raceway needs a direct path through the web and It is critical to know hole diameters and the allowable region in the joist. Drilling through any of the two flanges will be an expensive repair lesson red tag from the framing AHJ. (Especially midspan) The best bet is to Google up TJI TRUSJOIST MACMILLAN for their online catalog that illustrates the drilling areas and size allowances for data using OSB particle board. There are also joist webs manufactured with plywood in the industry that have different span deflection requirements affected by drilling. Best to check with the GC also. rbj, Seattle
 
As far as these trusses go I only use the pre punched holes that the manufacturere provides.I was on a town house job a couple of years ago in which the mechanical contrator wanted to know how does he get his return to the area on the print.The truss manufacturer was contacted and an engineer came and said,well take out the entire web of the truss in the middle not in the 1/3 area I was inclined to believe was the safe area but they took out the entire web in a 12 in truss ,dead in the middle of a 20 ft span.Installed the duct work and it passed the mechanical and framing inspections.Not my home and well I`m not an engineer but this is what the manufacturer`s engineer said was OK so they did it.
 
The manufacturer?s specs supersede.
Some of the above answers are less than accurate.

Talking about structural issues here is like when the homeowner asks a question in this forum!
 
As others have mentioned, the joist manufacturer will have catalogs or pamphlets detailing exactly what size holes can be cut and the locations where they can be cut, along with the minimum distance between holes. One manufacturer told us at a seminar that they staple a pamphlet on every 3rd joist for use in the field. I've yet to see these in the field, though. Must not be a manufacturer that's popular in this area.
 
I-joists have a much better tolerance for drilling than dimensional joists. You are allowed to make a larger hole in the center span of an I-joist than towards the bearing points. An inch & half hole is aloowed any where in the span. That is the size of the KO'S in the joist. When you need a larger hole, it needs to be twice the diameter of the larger hole to the next hole. A 4" hole will need to be 8" from the next hole, etc. Just be careful when you get close to the bearing points. The install guides will give the all the specs you need & are readily available, as others have said. You can also drill multiply LVL beams if you know where to drill. Again, the specs will tell you. Ron
 
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