My home will be getting painted in a week or two so I want to better repair a section of missing concrete/mortar above a basement sliding door so it can be painted and sealed. It appears that some chunk was broken out at some point, where a lot of (now quite old) foam was added. This is an area at the top of the sliding door along a metal plate that supports the framing above that houses the door.
Inside you do not see the foam, so it encounters some amount of concrete/rock before it reaches the interior.
My question is, after I get that foam out of there, what should I fill it with? Quick set concrete? Mortar? It really just needs to be whatever is best shaped and then can be ready for paint, that foam has obviously not been supporting anything for a long time, and that area appears to be just fine.
The foundation around it is generally old limestone and mortar, but this area also has some block and had some kind of parge applied over it, as I expect it was added later (I have no knowledge of how this basement area was built out or added). I do not intend to try to match the parge for this small of an area, and it appears to have some sort of hair or fibers in it anyway so it wouldn't be worth the effort to try.
So long as this region is paintable and reasonably flush, they should be able to scrape then caulk all around the cracked out parging and paint the slightly surface rusted metal framing and parge/cement. You can see how the parging appears intact along the vertical side.
So, mortar or quick set cement? Does it even matter?
Also, while I'd prefer they can deal with the cracked parge with paint (I still need to spend some time caulking around the bottom of this door and patching cement on the ground in this recessed entryway) would it be better to chip that out and slap some parge (type S?) alone that ridge. What is best to parge that tiny area of rock that has had a bit of parge come off in that top corner so the inside "frame" of the door can all be painted?