Safe to screw in a M10 screw hook into 30mm joist?

[Sprogginz]

As the subject line says I would like to screw a M10 hook into a 30mm thick joist in the loft.

I want to screw 2 hooks into separate joists to hang a bar for pull-ups. If I was screwing them into the first floor joists then I know that would be fine as the joist are thicker.

I believe the weight isn’t the problem but just wondering if the thickness of the screw would compromise a joist of this thickness since it leaves 10mm on either side?

Is there a general rule to follow perhaps?

Thanks very much.

 

[nickjb]

When I did similar I screwed the hooks into a bit of 2x4 then screwed that to the joists with 5x100 screws. It spread the load over an extra joist and hopefully the 5mm screws are less likely to weaken the joists

 

[Sprogginz]

When I did similar I screwed the hooks into a bit of 2x4 then screwed that to the joists with 5x100 screws. It spread the load over an extra joist and hopefully the 5mm screws are less likely to weaken the joists

Thanks, I'm toying with a similar idea of having something like 2x4 on top of the joist instead with long J bolts going through the ceiling then into it and secured with washer & nut. Just need a long enough bolt or something else that would do it.

 

[geraldthehamster]

The screw isn't going to compromise the joist, but I'd be concerned about the weight applied to the joist from the pull-up bar. How deep is the joist? Generally, ceiling joists aren't designed to have people hung from them.

cheers
Richard

 

[chappers]

That would be my concern too a 30mm joist is likely to be a manufactured truss which isn't really designed to hold much more than it's own weight and the ceiling.

 

[Sprogginz]

Thanks, it's 100mm deep. Is that not deep enough? If not, would putting 2x4 across the top of the joists and using bolts in the 2x4 instead make a difference?

 

[chappers]

spreading the load over several joists would make a difference but again ceiling ties and particularly trussed roof bottom chords aren't meant to take much more weight than the ceilings they hold, they're not designed for live loads.
However that being said you would expect either to take the weight of a person, but how they would hold up to the active load of someone doing pull-ups is another matter. What about one of those bars that fit into a doorway