ECN Forum Forums Code Related Discussion Building Codes for Electricians Floor Joists

The International Residential Code, section R502.8.2 forbids such acts:

"Cuts, notches and holes bored in trusses, laminated veneer lumber, glue-laminated members or I-joists are not permitted unless the effects of such penetrations are specifically considered in the design of the lumber."

To me this would mean engineering approval. Many I-joists have K-Os in the approved areas. All engineered lumber comes with literature that should be consulted when cuts are considered.

A general rule of thumb out here for cutting holes in joists is that they must not be cut in the center 1/3 of the member, but in the outer 1/3, the closer to the point of support the better.
I think that I'd want engineering. At least if they "crunch" the numbers, I'd not be accountable if the joist "crunched"

Electure: Your description is great, if you are dealing with sawn lumber (2X10, 2X8, 2x12, etc.), if you are dealing with engineered lumber, such as I-joists, it is exactly the opposite. As strange as it sounds, it is much better to drill an 8" hole right in the middle than to drill a three inch hole a foot away from th ebearing support. I know it sounds strange, but thats what the guidelines that come with the products state. It is also waht the engineer's will tell you.

Ryan,
Thanks.
I didn't know this.
We've been doing the TJI joists, apparently, incorrectly.
(best laid plans of mice & men)
I'll want a cut sheet before I do another.

[This message has been edited by electure (edited 01-16-2004).]

On the topic of being a pseudo engineer, I agree that the libility can be severe if one takes it upon themselves to "engineer" a portion or all of a project without the appropriate credentials.

Not withstanding, it is important to know where to get the best engineering possible. Go to the manufacturer to get the best possible data on questions and/or products that present a solution to an engineering problem at hand.

With that in mind, engineered floor and roof joists are becoming the replacement for dimensional wood products.

The question of "holes" and where can they be cut is not frivolous. The structural integrity of a floor or roof can be destroyed with the inappropriate installation of air ducts, plumbing and electrical lines.

I have found the folowing information re: holes, on page 24 and 25 of the JAGER US Residential manual very informative.
http://www.jagerbuildingsystems.com/pdfs/guides/USA/us_residential.pdf

For the ultimate flexability the "Space Joist" design with open web integral with an upper and lower Chord is the best system that I have found to date. There is a premium to pay for the joist but when the trades are considered, the overall capital costs are lower.

For anyone interested, JAGER also provide software to assist the project manager or residential contractor test various products and their design capabilities. I have had great success in knowing what I want before I contact the truss manufaturer. Good to be aware of the alternates for competitive quotations as well.

Doug.....et al (who is this al anyway?)


[This message has been edited by DGT (edited 01-16-2004).]

Not to be a pain about this but here is the site for the "Space Joist"
http://www.jagerbuildingsystems.com/english/products.htm

Up, up and away......

Doug......et al