[Rav]

The walls in the basement in our 1930-era house are made of clay block (sample drawing below). I have two items I need to secure to the wall. One is a very small (7 inch long by 3 inch wide) shelf, which will be secured with brackets underneath the shelf. The other is a piece of wood 2-ft long, 4-in wide, 3/4-inch deep which will be secured flat directly to the wall. Are Tapcon screws and a masonry bit the correct thing to use in this case, or ... ? And will a regular drill work well, or should I get and use something like a hammer drill? Thanks.

 

[jagans]

I would use urethane sealant and forget about drilling that block. It is hard burnt, and is hell to drill, and usually just breaks apart when penetrated. Attach a galvanized flat truss plate to the back of the wood on both ends with flat washers under the plate to space it off a bit. Clean the plate with alcohol. Same with the block. Put a glob of sealant on both plates, and stick to the block where you want it. Prop it in place with a 2 x 4 on an angle. Let it set up. You will play hell getting it off. :laughing:

 

[Windows on Wash]

Glue it like James said or if you want to drill it, do not use the hammer function and use one of the plastic or epoxy anchors.

You don't want a bunch of expansion back there or it will fracture it.

 

[jagans]

Have you ever tried to drill that stuff Eric? If its the stuff Ive run into its like iron, except harder and a lot more brittle. Maybe its not like the stuff in ancient roof decks.

They might actually be better off hanging the shelves from the joists above if they have any.

 

[Windows on Wash]

James,

I think I have drilled some similar stuff before. If I recall correctly, I wound up using a glass cutting bit instead of a masonry bit.

It is rock hard but brittle.