Owool12

Makes sense, I’ve also seen some people online suggesting leaving a 10mm gap for the backer block (the ply against the OSB) either at the top (so between the ply & top flange), or at the bottom (between the ply & bottom flange). Others have said just to fill the entire gap between the flanges with ply (no gap whatsoever). Any ideas why people suggest these gaps and which would be most appropriate? I assume it’s related to where the tension is being applied on the joist?

Cheers for the diagram, I agree I probably would get away with screwing into the bottom flange but I’m reluctant to do so just on the basis that it’s strongly advised against… ultimately damaging/splitting/cracking a joist is a huge problem I don’t want to encounter. I like both those ideas, keeps it relatively simple. Another approach I was considering was screwing some plywood to the inside of the OSB and then using a face fix joist hanger to run a 2x3 joist between:

Thanks! How would you recommend fixing a batten to the top and bottom flange/cord? Would I be better screwing into the OSB web to attach the batten?

Thanks everyone for the insights. The extractor is 30kg so with the frame and other plasterboard it’s probably about 60kg at most. The load will only be spread across two joists, so that’s why I’m concerned at fixing directly to the bottom flange. I’m happy cutting out the ceiling plasterboard to access the web, but accessing it on both sides is a bit of a pain. Am I able to attach a wooden batten between the top and bottom flange then screw horizontally into the web perhaps?

Sure that’s doable, but a dropped ceiling made of wooden studs, a 30kg extractor fan & plasterboard weighs a lot more than just ordinary plasterboard. I’ve heard about padding the OSB web with some plywoood & screwing through that with a joist hanger to hold a perpendicular joist… anyone any experience with doing that?

Hi everyone! I’m wanting to build a dropped ceiling out of a wooden frame and attach to existing ceiling joists. However the ceiling joists are engineered I joists (with OSB web) and I’m struggling to identify the best way to hang the dropped ceiling from these. I understand attaching directly to the bottom flange is a big NO when it comes to I joists, does anyone have any suggestions of how to hang from these joists? Cheers

Thanks for the advice everyone. Turns out I have engineered i joists… rather than traditional wooden ceiling joists. How can I safely attach a dropped ceiling frame (with ~30kg extractor fan) to I joists?

Nice kitchen, something like that dropped ceiling is what I’m aiming for. In my opinion I feel that wood will be cheaper than MF & easier to work with so am wanting to work with wood for this

Thanks for the idea! How would you recommend attaching 2x2 noggins to the existing joists? In addition, how would I attach the downward timbers (going to the floating frame) to the noggins? Would I be best butting them up side by side and screwing them in horizontally to the noggins?

Thanks for the response. The extractor unit is 20kg so I’m thinking 2x1 won’t be strong enough… especially if the entire dropped part of the ceiling is attached to just two noggings between the ceiling joists?

Hi there, I’m replacing my kitchen cooker extractor with one that’s built into the ceiling (similar to https://www.myappliances.co.uk/cata-art10238-stellar-90cm-ceiling-cooker-hood?gclid=CjwKCAjw44mlBhAQEiwAqP3eVogVcIy2T-b4yxnC7H6Hq3hzB5YCzx9jYEhfcVTumARa45z15gxF5xoCLXUQAvD_BwE). To achieve this I’m planning to build a dropped ceiling with a wooden frame. The ceiling joists are 24" apart and run parallel to the way that the ceiling extractor will be fitted. As such, I’m planning on installing some noggings between the joists so that I can then attach a wooden frame beneath (the dropped ceiling), and then clad with 12mm MDF. I’m thinking of using 95mm x 45mm C16 timbers for the noggings and for the wooden frame. However, I’m unsure of the best way to fix to the existing ceiling joists… should I use a metal joist hanger? If anyone has any advice or suggestions of how best to construct please let me know! Thanks in advance!