ECN Forum Forums Code Related Discussion Building Codes for Electricians Drilling a floor joist?

Bill, thanks for the 'shameless plug.' I had forgotten about that gizmo - and in my upcoming job it looks to be just what I need.

In the past I have done the 'chalkline and template' method, but this tool looks to make it a lot quicker. It would also work if the joists, etc., are not all the same.

I would be curious to see a side by side test. (Chalk line/jig vs laser) Sometimes old school turns out to be the best way.

Here is the code section that applies it is from the 2006 IRC. The middle 1/3 can be drilled as long as the other rules for drilling are followed the restiction on the middle 1/3 is only for notching.As you can see I split the section in half the first half is all about notching that is where the 1/3 restiction is the second half is for drilling.

R502.8.1 Sawn lumber. Notches in solid lumber joists, rafters and beams shall not exceed one-sixth of the depth of the member, shall not be longer than one-third of the depth of the member and shall not be located in the middle one-third of the span. Notches at the ends of the member shall not exceed one-fourth the depth of the member. The tension side of members 4 inches (102 mm) or greater in nominal thickness shall not be notched except at the ends of the members.

The diameter of holes bored or cut into members shall not exceed one-third the depth of the member. Holes shall not be closer than 2 inches (51 mm) to the top or bottom of the member, or to any other hole located in the member. Where the member is also notched, the hole shall not be closer than 2 inches (51 mm) to the notch.

Welcome to ECN, Paul!
Enjoy your stay here.

All the above rules should apply to simply supported natural timber beams in which stress and deflection are maximum at center span and near enough just in shear at the wallplate. Structural timbers built up as trusses, [usually factory made, that is triangulated assemblies using fish plates, toothed connectors, bolts, etc.], should not be cut or drilled at all. That's because the stesses are about equal throughout the length and across the section, usually with minimal bending loads in addition to tensile or compression. The stresses are high and the timbers are strictly graded for purpose. "Manufactured" lumber 'I' beams also need care when drilling if hole location options not marked by the maker.

All right Mr. Belson,

I KNOW I am going to regret this, what is a "fish plate" ?

Larry C

A good point, Alan, building on my earlier comments.

Should anyone wish to drill through a manufacturered assembly (such as a TJI or glulam), they should know that the rules are different than they are for dimensional lumber. VERY different.

Most standards on this topic are found, free of charge, either at the manufacturers' web sites, or at www.apawood.org .

FWIW ... I ordered that fancy laser tool from this site, and was amazed at how quickly it arrived.

I still have not used it, though ... it does NOT include the laser! It's made to work with their laser level. Maybe I should read the descriptions better next time.

Oh well ... in for a penny, etc.

Couldn't you just use a regular $2 laser pointer clamped into a big Romex connector? Drill the first hole a little smaller than the thread of the connector. Screw the connector with the laser in the hole and drill the rest.
I am sure you could dig around in your connector and adapters to refine this idea, maybe use a RMC to RMC connector for a bushing in the first hole to make it more stable.

Greg ...not to get too faroff on a tangent,I DO plan to usethe magic gizmo, and compare it side-by-side with the traditional measure / template method. I will then post a review thread on this site, probably in the general forum.

Off the cuff,the gizmo looks to be both fairly secure and you're able to make fine adjustments. You can also set it to specific amounts of slope (though that's more useful if you're a plumber).