How To Cut an External Cornice
External corners can be daunting to cut because these are the corners that people notice , the ones that stick out .
The cut is the same as an internal corner still a 45 degree angle just the mirror image . Once you have mastered the internal corner of our previous guide this one clicks into place pretty quick.
Watch the short video below to see an external corner cut from start to finish, then scroll down for the step-by-step photo breakdown.
How To Cut An External Cornice
How To Cut An External Corner
Follow these simple steps to cut a External 90 degree corner.
Place Your Cornice In The Mitre Box
Measure the wall length and mark your cornice, allowing a little extra at the corner end it's easier to trim back than to start again.
Position the cornice in the mitre box the same way it'll sit on the wall ceiling edge up, wall edge down. Getting the orientation right is half the battle.
First Cut
Place your blade in the 45 degree slot as shown.
Cut with steady, even strokes. XPS foam cuts cleanly with a fine-tooth saw, so let the blade do the work rather than forcing it.
Second Cut
Repeat the cut in the opposite direction for the matching length the two 45-degree faces meet to form your 90-degree External corner.
Dry-fit both pieces before gluing. A clean join should sit tight with no gap; a quick trim now saves mess later.
Making the external corner
The cut from the right hand side will sit on the wall at the left hand side . The cut from the left hand side will sit on the wall on the right side ,