ECN Forum Forums General Topics of the Trade General Discussion Area Drilling beams?

In drilling standard wood beams, the rule of thumb out here has been to keep the holes within the outer 1/3 of the spans. Most inspectors like them within a foot of the supports. Drill through the center of the span, and you'll be buying somebody a new beam.
Gluelams, as used in our tilt-ups, are seldom drilled, as you can normally pass under them.(They aren't as strong as they look, they only hold up the roof)
For Engineered wood products, such as TJI joists (the waferwood or plywood jobs with a top & bottom chord) we always have to contact the manufacturer for their requirements, as they can vary.

Bill,
The beam runs from the rear of a townhouse forward. I don't know how long it is, but I drilled a 5/8" hole about 2-3" from the bottom, and about 24" from the end. I doubt that any appreciable harm was done, although during construction I'm sure that everyone can't just indiscriminately drill as they please. However, I wanted to get some opinions for future reference.
Thanks, everyone.

[This message has been edited by Redsy (edited 11-04-2001).]

Electure,

Are we talking about the same stuff?
http://www.apawood.org/glu_level_b.cfm?content=prd_glu_main

Redsy,

Yes, it looks like you really can't just drill any size hole wherever you want it.

I found some good info: (get PDF at end)
http://www.anthonyforest.com/stockfaqs.htm
(cautions to read the following before notching, drilling, etc.)
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This comes from a 6 page PDF file that looks pretty good entitled: "Field Notching and Drilling of Glued Laminated Timber Beams"

Note:
The construction of these things are not uniform, so there are zones that are definitely better than others.

Get PDF File

Bill

[This message has been edited by Bill Addiss (edited 11-04-2001).]

When requested to replace said beam, I would simply request to see my contract...

There are advantages to the "no contract" way of doing things...

I've drilled 2" holes in glue-lam... If they didn't like it they can find somebody else...


Muahahahahahaha! (Evil laugh)

Wow!

That's really different than plain old Wood!

Al,

That's a interesting PDF file. isn't it?

Bill

Bill,

THANKS!
That was EXACTLY what I needed.

Redsy,

It looks like you drilled in a good spot!

I've only done custom resi work and many times these beams are waaayyy oversized and drilling wouldn't be as critical, but it is good to know this information anyway. They probably oversize just to be sure and don't care as much about cost because they are not buying a lot of them. I'd imagine that in situations where many beans are needed (many similar structures going up, Condos, Townhouses, etc.) for economic reasons, they would be sized more closely to the load served and therefore have less tolerance to field modifications.

Bill

[This message has been edited by Bill Addiss (edited 11-04-2001).]

This is from the 1988 UBC. I do not have a later version but should be similiar.

Notching and boring for wood joists that are structural members:

Notching can't be done on middle third of the joist.
Notches on the end can't exceed 1/4 the joist depth.
Notches in the top or bottom between the end and 1/3 joist length can't exceed 1/6 the joist depth.

Bored holes can't be within 2" of the top or bottom.
Bored hole diameter can't exceed 1/3 joist depth.


Gerald Powell