This is coving tips from Plaster Ceiling Roses I'm just going to talk you through how to cut an internal mitre. Okay so the first thing we need to do is make sure we have the cornice the right way up. We need the the ceiling closest to you and the wall edge furthest away. Then we square up a line on the cornice. using the saw. Make sure we can see them marks. Then from the top edge we take away the projection of the cornice. Make a mark so you can see them again. And then to cut the actual mitre we're going to need another pair of hands. So with the other pair of hands we lift the back up and hold it at the correct depth. OK. Have you got it? Then we need to make a saw cut from, this is the bottom edge of the cornice to the top edge. So we're taking away to create the internal. Let the saw do the work. And we now have a 45 internal mitre. So we've done one internal this is the opposite internal. We have our square end ceiling and wall edges of cornice. Taking off the projection. Again the other pair of hands will hold the cornice at the correct depth. And then we cut, yep, we cut straight through our marks. Okay so now we have their first piece we cut, this being the wall edge this being the ceiling edge. The second piece fits perfect and we now have a perfect 45 internal mitre.