As the guys have said, use stop beads on obtuse angles.
If you mechanically fix them i.e. screws or nails, go easy as they can distort easily. Otherwise use adhesive but apply the first coat of skim carefully as to not disturb the bead.
If you need to find a tradesperson to get your job done, please try our local search below,
or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Please select a service and enter a location to continue...
Are you a trade or supplier? You can create your listing free at DIYnot Local