I need to secure a shelf to an old cinder-block wall. My experience with these walls is the anchors frequently work loose due to the low density of the block.

I want the shelf to be able to hold 100 pounds, so I need a strong, reliable anchor.

Any suggestions?

Thanks!

 

If the walls are hollow, use toggle bolts.

 

Thanks, but I doubt toggle bolts will do the job. They may not pull out, but they will likely get loose.

 

Always anchor in the mortar joints of cinder block walls.Most anchors will function well.

 

I don't know why toggle bolts would come loose. I have used them several times to hang cabinets on and never had a problem. I went directly into the block and not the mortar.

 

Toggle bolts would not work in the mortar,they need open space to function therefore you'd have to drill into the open part of the cinder blocks.

Using a VSR drill with a masonry bit going slow might get you a hole that wouldn't be oversized and lower any risk of breaking the block sidewall.

 

Red Heads Concrete Anchors are the way to go I never use anything else. Go right into the block not the mortar.

 

I use the WallDog sold in Lowe's. They DO work. It's a Screw and Anchor all in one for drywall, brick, metal, concrete. I work for the company...LOL.
In my demonstrations I hang a 50 lb. box of nails from one in a cinder block. I think they'll hold up to 500 lbs. in concrete.
In sheet rock they'll hold up to 50 lbs. I use them to hang my medicine cabinet, mirrors, towel bar and toilet paper holders instead of the anchors they send with it. I recently put up shelving into sheet rock with them and also hung my curtain rods with them.
They even make ones to hold 250 lbs. in sheet rock.