I'm attempting to hang window flower boxes (a metal frame with a moss/fabric insert, filled with dirt/flowers/water for a total weight of about 15 lbs) on a brick wall.
An example of a similar metal frame can be seen below (found at http://www.vintagetub.com/asp/product_detail.asp?item_no=B-30&utm_id=IDK14&cvsfa=1353&cvsfe=2&cvsfhu=3439353934): Flower Box http://www.vintagetub.com/images/medium/m_B-30.jpg
The specific box I have has two vertical support beams towards each end with a common vertical set of holes on a each of these that will slip over the head of screws that are firmly anchored into a wall.
I've got two concerns:
Can I support this load via screws only in the mortar or do I need to drill the brick? (A mortar repair is easier and more sightly than holes in brick if I ever take this down, since it's on the side of a garage - i.e. a large uniform brick surface - instead of directly under a window where the holes might go unnoticed.)
If mortar alone will support the expected load, would using only the top two screws suffice? (I'd suspect not.) The distance between the holes in the box is not the same as the height of the brick, so at best I could only get 3 of the holes (two in a horizontal line of mortar, and one in a vertical line) used without drilling brick or coming up with some other way to fasten the box to the wall.
I'd appreciate any thoughts at all on the matter!