How can I accurately locate bricks covered in stucco or plaster?

Question

Where I live, most houses are old and have red brick walls. On the inside, the walls are covered by stucco or plaster and then some decorative layer. The plaster and mortar in the walls are generally very weak. So when you need to attach something to the wall, you want to drill with a hammer drill through the plaster into the middle of a brick.

The only way I know of to drill into the bricks and not into the mortar is by trial and error and by looking out the window, where the bricks are visible, to guess the middle of the row of bricks.

I am looking for a more reliable way to find the right spot where I can drill. Is there some kind of scanner or instrument that can be used for this?

Answer 1

While this doesn't answer the question directly, I question the need to know where the bricks are when hanging items indoors. Unless the load on the anchor is going to be axial rather than lateral (ie, pulling rather than hanging), the bricks above and below should still provide support for the anchor even if you are in a mortar line.

Alternate Solution

Perhaps using a different anchor style would solve your problem. One that flares more when tightened, to better embed itself in the mortar. Combine this with epoxy to further increase the strength of the anchor.