You can always trace the shape in front view and extrude it to a small thickness then, in plan view, drag it to be just in front of the dormer fascia. Render this shape to whatever material you wish the facsia to be
I prefer to use shaders for brickwork rendering, but those available do not show a British size brick!
Is there any way of editing shaders to change the proportion of the bricks to 215mm x 65mm ?