I am mounting a projector on the ceiling in my single story extension with a sloped roof.

My luck had it that there was a joist within range and I proceeded to drill into it from below through the plasterboard ceiling and fix the bracket as I thought this would be the best support.

Now, afterwards, I am concerned that I have weakened the joist and that it may become an issue.

I have attached a sketch that shows approximate dimensions.

The projector and mount will be approx. 13-14kg (28-31lbs) max. In weight.

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You have not weakened the joist in any meaningful way. Even if you had run half inch lag screws into it, the remaining material is more than adequate.

  • Thanks isherwood for your response. This joist is towards the centre of the extension - not sure if this makes any difference with weights etc.. The "approx. 450mm-500mm in from end" refers to the end that the 'A' frame of the roof is attached too. You most likely understood that but adding just in case 😀 Thanks. – user91821 Oct 7 '18 at 20:06
  • It's just not an issue. Lumber used for joists can have knots larger than the bolts you've described. Carry on. :) – isherwood Oct 8 '18 at 1:14
  • Many thanks again Isherwood. I'm looking forward to hooking up the Projector and enjoying some movie nights 😀 – user91821 Oct 8 '18 at 20:52

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