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I know the regs for the regular notching of joists, but I can find nothing about notching up the side of a joist. I need to route my cables up past a large wooden beam 4500mm x 400mm, 115mm thick. Do the normal rules apply? 0.07-0.25 of the length and 0.125 of the depth? Or is it a no go?

Cheers
 
I'm sure the building regs only give the top of a joist as safe to notch, so I would say a no go if it's a load bearing joist. If it was a noggin in a stud wall, then I usually wouldn't have an issue with that.
 
I'm sure the building regs only give the top of a joist as safe to notch, so I would say a no go if it's a load bearing joist. If it was a noggin in a stud wall, then I usually wouldn't have an issue with that.

My thoughts exactly, but yes it is a load bearer. The builder has just told me he's oversized it by 25mm so it won't be a problem, so I've told him to notch it himself as I won't be putting my name to that!
 
I think I'd be trying to find an alternative route truth be told. Even if he notches it, all people will see is your cables running in the notch and people will naturally automatically assign that to you.
 
Agree with HT, best to find another way. Making any vertical full width cuts in a load bearing joist is just asking for trouble, probably why they don't mention it in the regs (?). The phrase "tear along the perforations" comes to mind :)
 
Murdoch - no, he did however have a structural engineer calculate it smaller than the one he's put in.

Vortigern - it's being directly overboarded.

Hightower and Wilko - completely agree.

As I said, I wasn't sure if I was missing something regs-wise on this one as I couldn't find anything about notching other than tops of joists, which, you're probably right, is because it's a no go! Cheers all
 
Watched a plumber drill an 18mm hole straight down through the middle of a floor joist to fit a rad pipe the other week! The floor is still there at the moment though.
It will be fine until they put something heavy in the room, like me and my toolbox :)
 
I'm doing my kitchen up at the moment, after removing the four layers of ceiling I found the ends of the joists in one corner have rotted away and are hardly hanging on to the brickwork. Scary stuff really, they have been holding up the bath and washing machine for years.
 
I can't see a problem with it either. Providing it's in a prescribed zone and is only deep enough for the depth of cable. I've seen so much worse than that especially on refurbs. If the beam has been designed so close to the limit that a 6-8mm notch on the side causes it to fail then you have to question the spec of the beam.
 
As the beam is a modern manufactured product - why not ring the manufacturer and see what they advise?

Are you serious?? How long do you take to complete jobs, if your going to track down manufacturers of beams and ring them uo to see if you can notch it.? They'd have a right laugh at u phoning up about that! Get on with it
 
The strength of a beam in the lateral direction is directly proportional to the width (in this case 115 mm).
In the vertical load carrying direction the strength of a beam is proportional to the depth cubed (in this case 400 mm to the power 3 ).
Therefore the vertical load bearing capacity is most sensitive to changes in the depth.
 
Taking on board Bigspark's feedback - I contacted my glulam beam supplier and proposed a 20mm wide by 10mm deep vertical notch for cables in their 115 by 400 by 4500 glulam beam. Their structural engineer approved it, as long as it was not in the middle 1/3 of the beam. I was pleasantly surprised with the 2hr response time, and by the answer. Of course, this feedback only applies to that manufacturer.
 

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