LVL's

[Joshua Hardesty]

Okay, I know that you are VERY limited when boring holes into LVL's, but how about this situation:

I was building a house with two bathrooms side-by-side. There was a joist that was running across where two toilets and the center of the tub needed to go, so we asked the framers to come move the joist. So they do, but they use LVL's instead of regular lumber because they didn't have any. Framer tells me I can treat it like regular lumber because it's just being used to replace regular lumber.

What are your thoughts on this? Can I have my way with it, or is the structure of LVL's such that a 2" hole bored through it will significantly weaken the board, even if it's not being used to bridge a significan span?

[Tim Lorenson]

Joshua,
We are talking thick piece of plywood here right?
Less subject to defects in any of the veneers.
In solid lumber you must watch out for grain defects and knots as they are equivalent to a hole their size as far as weakening a framing member.
LVLs should be safer to bore than solid lumber because of the lack of other weakening defects, just keep the holes in the center, (and keep to the allowed percentages).
cutting near top or bottom will greatly reduce strength.
Also don't cut /bore where subject to compressive load as the LVL could be crushed.
How tall is the LVL? If it is 8 inches or more, then a 2 inch hole is only 25%, which I believe is cool.
If you are running 2 inch ABS, the the hole will be bigger than 2 inches.

You might want to talk to the people who will be inspecting the work as they have the final say.

I just repaired a home where the plumbers notched 2 joists 50% at the bottom side for the 3 inch toilet pipes, (made 5 inch notches), the floor was sagging a bit...

Tim Lorenson

[Markus Keller]

Easiest thing to do with LVL, microlam is go to one of the manufacturer website's and download one of their pdf's that shows how and where it is ok to cut.
Try APA - The Engineered Wood Association (http://www.apawood.org), there are also many others