I don't undestand why you can't answer most questions when the lights are removed. It's going to require drywall repair either way.

Sorry if it wasn't clear, I'd only remove the lights if it would actually add ceiling height, and I'm trying to figure out if it would. The drywall ceiling in a 100 year old house makes me think they might have dropped the ceiling, but I don't know. I don't love the recessed lights, but I wouldn't go through the hassle/expense of removing them unless it resulted in additional ceiling height.

There are some pros here who will be more useful than me, but until they get here I would suggest that it is certainly possible that you could gain some or even a lot of height. Of course, you might also find the only rafters right there with the can lights sitting in between. The obvious reason for two ceiling potentials is old houses often had high ceilings and heat loss was sometimes an issue.

I was surprised to see how solid the can light connections are. I don't believe you can remove one from inside of one. That would be a simple way to check, but.... Instead, you will have to remove a rectangle of sheet rock between two rafters (or what ever is up there) so that you can look up and around to see what's going on. You can always just smack out a small hole and then enlarge it so that the hole extends to adjacent rafters and exposes half of each so that a replacement scrap of sheet rock can be nailed back in the spot. Then of course there is taping, mudding, sanding and painting. All assuming you don't find a new better solution.

pelpram,my experince can't make you experienced,all I can do is give you tips here and there. Common sense tell's us someone had access to the vacant space above your ceiling while they installed recessed lights. All you have to do is remove bulbs from a light fixture and figure out what the last step was to install fixture then reverse the process until you are looking at a hole in ceiling. There are dozens of ways lights are assembled in a ceiling and if I were looking at yours I could tell you which was used in your home.. Bottom line,gearheads can just figure it out by looking but an engineer can't tell you unless he see's it. Does that make sense or do you feel there's a one size fit's all silver bullit answer? What I'm trying to tell you is it's not nessary to poke holes in the ceiling,there's already holes there with lights in them. Just remove one or more lights and you have holes to peer into. If all this is greek, just do as most people do and pay someone to do it for you.

Here is the way to tell your true possible ceiling height. First go to a corner of the ceiling away from the can lights, at least a foot in any direction from the visible can. Then tap on the ceiling, if it isn't hollow at any point the sheetrock is directly over the plaster. If you find a hollow area drill a hole large enough to insert a long screwdriver, I use a 24" long. Mark with tape on the screwdriver how far it goes and you will have your true possible ceiling height.

Poke a hole in it and look. Not worth the time it takes to discuss it. Use a hole saw to make a big enough hole that you can see what is going on. Save the cut-out piece to patch the hole if you decide to leave it alone.

If the cans are remodel versions they are easy to take out, if they are nailed to the joists, not so easy.

Thank you all, very helpful. Fingers crossed there's some room up there.

If for some reason you cannot disassemble a can light to see if you have a dropped ceiling, you could get one of those inexpensive inspection cameras that plug into your phone.

Then you only have to drill a small hole, which is really easy to patch up. Plus the camera could come in useful for other things.

sam I saw on the evening news where some feller got into a mess of trouble over one of those cameras. (:

Straighten a wire coat hanger and push it thru the ceiling sheet rock.

Everyone has their favorite tool. lol

(Some people will not drive in a Thunder Storm out of a fear of being struck by lightning.)

I'll stand with my proven wire coat hanger. YMMV

Coat hanger or screw driver will work in telling you height.

But an inspection camera will be better able to tell you what is up there.

For example there could theoretically be a bunch of plumbing venting up there. And for some reason this is the only place it could go which is why the ceiling was dropped. That example is unlikely unless its a kitchen or a bathroom.

Another more likely possibility is the walls were re-plastered as part of the same project that lowered the ceiling. And the portion of the walls above the false ceiling are a level 0 plaster finish.

If the wire coat hanger tells you that there is, say, 18" more headroom, either an inspection camera or a mirror thru a larger hole would seem a logical second step. ( A 4" X 4" hole would allow you to put a mirror and flashlight above the sheet rock.)

Rehabbers in my town drywall over plaster ceilings and walls. I guess it is easier than fixing the plaster or removing it.

There might be clues in the house. Does any room have a higher ceiling? How high is the dining room ceiling? Does the room above the living room have any openings that you could look down into? For example, my bedroom, which is over the dining room, has holes in the floor in the corner and a floor vent.

To answer your question, you could take a hole saw and drill out a small hole. If you decide not to proceed with tearing down the ceiling, you put a piece of drywall back in, mud, sand, and prime and then paint the entire ceiling. (I would try at least one of the suggestions above first.)