ceiling covered with cement?

[EricU]

I took out an island cabinet, and there was a big, blocky soffet over it.  Unfortunately, the guys that built my house took advantage of these soffets and were really sloppy with the plumbing and wiring, so I couldn't take them all out, just the one over the cabinet. Anyway, I need to chip the ceiling back from the hole in order to tape the seams, and it's like cement.  It chipped in places, so it's not cement board.  When it chipped, I was hopeful I could chip it out, but now it looks like I'm going to have to use a grinder on it. It's over 1/4" thick.  The guys who drywalled put a really thick skim coat everywhere, so it wasn't unexpected, but having it be rock hard was.  Anyone ever seen anything like this? 

The surface of the ceiling is sanded.  Not sure how I'm going to simulate it, I would have to float a lot of ceiling to get rid of it.  It's impossible to flatten, and now I know why, the sand goes all the way through.

[mike4244]

If the finish is gray in color and hard it probably is plaster. Not the white gauging you usually associate with plaster but the first and second coats.
Instead of drywall cement you can have a plaster ( assuming you can find one under 90 years old) coat it with white gauging.I would not try this myself,plastering is not my expertise.Sometimes a taper may be able to do a serviceable job.
mike

[EricU]

It is gray.  I did a little plastering when I was getting my mom's house ready to sell, but it wasn't like this.  Actually had horse hair in it, but it did have similar consistency except it was based on clay.  Not up for this much plastering.  It's on a drywall backer. The seams were done with fiberglass repair tape.

Central PA is no longer the place to find skilled craftsmen like a plasterer. Can't even find a mason

[Phil Thien]

A competent drywall guy can do it.

Tell him you want the ceiling patched, primed w/ sand texture, and ready for paint.

[mike4244]

The drywall backing is actually a lath in 2' x 3' panels. I forgot the term used for this backing,it is similar to wall board.Originally wood slats were used for lath,later steel lath was used in high end installations.The backer board was used in homes with 3 coats of plaster .Scratch coat,brown coat and white gauging.Today " blue board " is installed and white gauging.
I believe your ceiling may be a single " brown" coat.
Usually the gray color is seen on homes 100 + years old. Is it feasible to remove a portion of both the lath and plaster?
Replace with drywall. I have removed plaster by sawing along each side of studs or joists with a Sawzall.Then sawing behind the lath to cut the nails free.If you do this,make sure every thing is covered,falling debris will destroy floors and any thing else it hits.You need a helper,dust masks,heavy gloves etc.Vacuum the dust as soon as possible.
mike

[bgosh]

The backing you referred to is called rock lath if I remember correctly.

[Estrogen Hostage]

The backing you referred  to is called rock lath if I remember correctly.

yes. rock lath. Skim coat of plaster over the top.

[EricU]

I'm pretty sure the top layer is just plain old drywall. 

Another issue I failed to mention is we have ceiling cable heat, and I'm trying to figure out where the heating panel is.  Getting rid of the cable heat is one of my near-term goals, but I'd rather not expand this project

on edit:
Found the heater coils, plenty of clearance. Maybe that's why it's cement?

I am just going to fill in the hole with 1/4" drywall and try to match the sand.