Here is a picture of how I cut my bricks. You can see that the bricks protrude into the doorway opening. I haven't found that to be an issue. All of the lower bricks along the grate are notched (see lower arrow on picture). In addition the front and back bricks in the firebox have an additional notch (upper arrow) to allow the grate to be removed. I firebricked the entire inside of the arch because I bought it used and it came with bricks so I used them. All I did was add insulation underneath all of the brick. InkedIMG_1358_LI.jpg