I am in the process of building a stable in an old barn and have discovered that the masonry arches above the windows are very bad, see the pictures. I would appreciate if anyone could give advice on what to do with them? Is there any "material" that can be injected into the cracks? Or should I support the arch and try to insert as much new mortar as possible? Or should I demolish everything and build it up again? I feel that I have too little knowledge to attempt something that could end badly.
