Drilling joists to get into loft

[turtlesnuts]

Good afternoon,

im putting in a concealed shower unit into a cavity wall. It’s going to need 2 x 25mm holes for hot and cold supply and a 20mm hole for the shower head feed.

every joistdrilling and notching advice I can see on the net is about drilling horizontally. But whatif you need to drill vertically into the loft?

do the same rules apply or does it not matter?

thank you if you can help

 

[exedon2]

We always space them 100mm apart in center of timber won't weaken timber and if nothing else makes lagging in loft easier.

 

[turtlesnuts]

Thanks for the reply, Is that 100mm from center of the holes or from edge to edge?

it’s a concealed shower valve so it’ll be 25mm 20mm then 25mm.

Are you allowed so many pipes going through?

 

[ShaunCorbs]

Normally go 2” between eg outside of hole to outside of others

 

[exedon2]

We go 100mm centres most of our work at first fix stage has to past pre plaster inspection , try not to give the building inspector any reason to mump.

 

[gpbeck]

The timbers you show aren’t joists, not structural, stud walling can’t be loaded.

 

[turtlesnuts]

Thanks everyone, I’ve marked where I’ll be drilling. Think it’ll be ok if none of its structural?

 

[exedon2]

All looks good just check there are no ceiling timbers in way before you drill.

 

[ShaunCorbs]

Yep fine but might be worth putting a pilot drill up first to check above like the above comment