Drilling in the joists

[Pottan]

I need to hole saw through some ribs in the intermediate floor (220) to get the ventilation pipe (105) in the right compartment, is it okay if I do this directly above a wall that is 120 (the core wall).

Norrl.

 

[Ola78]

Here you can read a bit about hole cutting in floor structures http://www.traguiden.se/TGtemplates/popup1spalt.aspx?id=1251

 

[Pottan]

Now I want to make a hole where the beam rests on a wall, so I'm wondering if the load-bearing capacity will be compromised by this, and if so, how I can reinforce it.

Norrl

 

[Ola78]

I don't think the load-bearing capacity will deteriorate significantly if you make the hole above the load-bearing wall. You could add some cross-bracing between the joists where the holes are to better distribute any potential load.

 

[JOW]

Well, you're not supposed to drill directly over the support. Looking at the link provided by Ola78 ("rules of thumb"), you can see that the maximum hole diameter for a 220mm joist is 110mm (h/2). The hole should be centered and at least 440mm from the support.

If you're going to reinforce it, I think the best way is to splice/reinforce the joist since it's the bending moment over the support that the joist needs to withstand, which is weakened by the hole. For example, plywood on each side of the joist, glued and screwed/nail. In a pattern like a die (5) on either side of the hole (but with more screws/nails between the two dots to the right and left of the center dot). And a splice length of about 120cm. Note that I'm just estimating above.

Maybe there is someone more knowledgeable who can confirm or correct my thinking...

 

[prototypen]

I am against having at least 440 mm from the support. It is better to make holes at the support.
However, one thing that applies to a whole floor structure is that the floor/beams on the other side of the heart wall act as a counterbalance and reduce deflection. A whole floor beam gets a "fixed clamping" over the heart wall and is negatively affected by the hole cutting.

Make holes by the wall, it holds, if you're nervous, glue-screw 45x45 on both sides at the top and bottom.

Protte

 

[JOW]

Yes, if you reinforce to replace the "hole," then you can place the hole wherever you want...

 

[prototypen]

Look what a "masonitbalk" looks like.

Protte

 

[anaitis]

If the beams continue beyond the end wall, i.e., if they extend over 2 spans, then the position at the end wall is the absolute worst point to weaken the beams. It is where the greatest stress, tension, occurs.