Material for door frame/arch?

[calle_d]

I have just cut out a large hole for an arch at home and am going to put up some wood material to cover the arch. First, you need to put a board to cover the cut surface, then you put up trim.

My question is, what materials can you use to cover the saw cut?
The wall is about 15 cm thick and it will be filled and painted with white lacquer paint afterwards.

 

[chris47]

There are ready-made modules where arches and casings are included that can be bought expensively. The economical version is to use something flexible such as masonite, thin plywood, or sheet metal.
/CC

 

[greenbay]

If the vault is straight, you can use MDF, it comes in different widths and thicknesses, white-painted and clear, except for the length. After cutting, you can glue it with adhesive onto the studs.
Regards
greenbay