How can I drill into cinder blocks and attack brackets?

Question

I want to affix some shelves to some cinder block walls. The shelves would be 3000 x 400mm. I have been eyeing up these brackets as supports. The shelves will be to hold power tools and toolboxes and will need to support a decent weight.

I'm completely in the dark about how to fasten the brackets to the cinder block walls. I'm eyeing up these fasteners but I feel like something that long would just be hanging loosely in the hollow cavity of the cinder blocks. Likewise I don't know if a shorter screw would support the weight involved and I don't know if the width of the screw holes in the brackets is big enough for these screws.

Normally I would just ask someone at the hardware store but quarantine means I need to pre-order and then go collect it.

Any advice would be gratefully received.

Answer 1

Those masonry screws work best in brick. The long ones are for attaching timber to masonry walls. but you can get short ones. eg: https://www.bunnings.com.au/ramset-6-x-50mm-zinc-ankascrew-masonry-anchor-50-pack_p2260248

Or you can use expanding bolts (sleeve anchors) https://www.bunnings.com.au/ramset-6-x-26mm-dynabolt-plus-hex-nut-bolt_p2263002, these take a 6mm hole but the shank is only 4mm. do not over-tighten - they snap real easy. the 8mm ones have a 6mm shank and are harder to bust accidentally.

Either way you'll have to drill carefully, too much pressure will blow out the inside wall of the block and reduce the amount of concrete for the fastener to grip to.

Your other option is to drill though with a large hole and use a toggle bolt.

https://www.bunnings.com.au/ramset-3-16-x-100mm-countersunk-head-spring-toggle-2-pack_p2260436

These want a 14mm hole, unless you have a rotary hammer drill you'll probably need to drill that in stages, eg first 10mm then 14mm. This one will fit a 12mm drill chuck https://www.bunnings.com.au/kango-14-x-150mm-straight-shank-masonry-bit_p6350319

Answer 2

In my humble opinion, you've got two choices using those brackets in cinder block. You can use 1/4" toggle bolts if you drill in the hollow section of the block or 1/4 or 5/16" lag bolts with lead shields for the solid area of the block. These are common items at your home store. Lag shields need a 1/2" hole drilled in the block and the toggle bolts need a 5/8" hole. A regular masonry bit will do the trick. Don't use a hammer drill. Good luck and stay safe out there.