I need to mount a 2.4 meters long section of 50mm x 25mm mild steel box section into the ceilings joists where it will support about 50kg of disco/stage lights. I also can't easily get above the ceiling due to a room above.
There also needs to be about 100mm between the top of the box section and the ceiling.
The M12 x 250mm coach bolts here: http://www.tradefixdirect.com/screws-accessories/coach-screws/bzp-coach-screws would do; but are rather expensive at £20 when I only need about 4 or 5.
Any ideas; Are Rawlbolts sutiable for hanging heavy loads from the ceiling?
Edit: My joists are about 40mm wide.
There also needs to be about 100mm between the top of the box section and the ceiling.
The M12 x 250mm coach bolts here: http://www.tradefixdirect.com/screws-accessories/coach-screws/bzp-coach-screws would do; but are rather expensive at £20 when I only need about 4 or 5.
Any ideas; Are Rawlbolts sutiable for hanging heavy loads from the ceiling?
Edit: My joists are about 40mm wide.