I'm replacing the old aluminum single-glazed windows with vinyl low-E triple-glazed, hurricane-proof, high-test windows. Because of the way the original windows fit, the generic replacements end up with a 1/2" to 3/4" gap around all sides at the outside edge. It's a brick house. I'm wondering what to use to fill up the gap that will seal to both the brick and the vinyl and look good. Ideally, it would look like the mortar in the surrounding brickwork, so I'm thinking of using mortar or a modified grout or something similar. Not sure it wouldn't slump out of the vertical gaps, though. Suggestions welcome.