Drilling joists vertically

[penguinlicker]

I don’t know if you would be able to help me. I want to drill 2 x 25mm and a 20mm hole through these joists to get into the loft.


Is drilling vertically through joists allowed? It’s a bungalow so there’s only the loft above but the only info I can find is about drilling horizontally rather than drilling inside a cavity wall up into the loft. Is there anywhere that advises on such things?


thank you if you can help

 

[Spoon]

There are called 'top plates' or 'head plate' and are not joists.
Not sure about the rules of drilling through these... I'm presuming it's allowed but I think there may be something that states what max size hole you can drill in a certain size of plate.
What is the width of the plate? The face that has '825' on it...

 

[littlespark]

Its a bungalow.... just drill what you need.

Non load bearing, you could take the wall down without it causing a problem.... no dont do that..

 

[Dartlec]

I don’t know if you would be able to help me. I want to drill 2 x 25mm and a 20mm hole through these joists to get into the loft.


Is drilling vertically through joists allowed? It’s a bungalow so there’s only the loft above but the only info I can find is about drilling horizontally rather than drilling inside a cavity wall up into the loft. Is there anywhere that advises on such things?


thank you if you can help


View attachment 62021

Guidance for that sort of thing is probably in Approved Document A - one of the documents that is actually available free of charge online to anyone...

But as mentioned this isn't a joist, so there should be no problem drilling through it - though it appears to be double thickness so you'll need a fairly good bit and drill

With joists the usual rule is a hole no more than 0.25 x the depth of the joist, between 0.25 and 0.4 of the length of the span, but for some reason this doesn't seem to apply to plumbers

If it's wiring that's going up, you should probably keep the holes as near the centre line as possible, to ensure the cables are as far as possible away from the stud wall either side. Looking at it they will be less than 50mm from the wall in any case, so will need RCD protection if they aren't already.

 

[hasel5]

Look to the right in the photo

 

[Spoon]

Look to the right in the photo

Yep, but we don't know the hole size, that is why I questioned the dimension of the plate.
I wouldn't want someone drilling two 25mm holes through both plates and only leaving 3mm of wood either side.

 

[Dave OCD]

Just be careful that the wall isn't directly under a roof truss, you dont want to be drilling through that, looking from above the existing cable hole in the loft will tell you whether it's fine to drill straight up through.

 

[Vortigern]

Go through the existing hole. If you are running cables up there they would need to comply with safe zone requirements. i.e. you cant just put them in the middle of the wall unless there are accessories going on the new wall.

 

[penguinlicker]

?Thanks everyone, that’s cleared it up

 

[Rockingit]

Experience has taught me that the further back you go the more likely you are to snooker yourself with whatever construction is above it (especially if it's an exterior wall and the roof plate is nearby) - so I quite often just 'half drill' a hole in the side, more of a notch, so that you can find the cable above OK.

 

[Dave OCD]

Go through the existing hole. If you are running cables up there they would need to comply with safe zone requirements. i.e. you cant just put them in the middle of the wall unless there are accessories going on the new wall.

Just thinking about that, if you were to drill exactly in the centre of a 100mm studwork top timber you'd achieve 50mm clearance on both sides within reason once the plasterboard was fixed. I've only ever treated wiring in solid walls which is never far below the surface as the real intention behind safe zones. But having said that you can generally get a socket/switch or even consumer unit in alignment with the hole/s.

 

[pirate]

It's not a problem to drill that, and as you have a pull-cord switch there already, that will be easy to identify from above, so easy to measure from that, to the left, and avoid any joist above. Use a pilot drill before attacking it with a spade/forstner/holesaw...easy does it!