My house is a fairly typical US split-level from the mid-50s. It has a two-car garage with the master bedroom and bathroom above. The garage ceiling is simply open floor joists, with some fiberglass insulation stuffed in at random, which of course doesn't meet fire code. We've only been here about a year but it doesn't look like there was ever any more ceiling than what's there now.
The obvious solution is to put up drywall per code; however I've been spoiled by only ever living in single-level homes with crawlspace or unfinished basement access, and it pains me to seal in that convenient access to the wiring, plumbing, and HVAC that runs to the bedroom and bathroom. Ideally I'd like some kind of ceiling surface that can be taken down and replaced in a matter of hours if I want to get behind it, without replacing or patching sheetrock.
The relevant part of the IRC (which my city and state follow), R302.6, states that garage ceilings below habitable space must have "Separation" of "Not less than 5/8-inch Type X gypsum board or equivalent."
The question: is there an established "equivalent" to the 5/8" Type X gypsum board required by code for a garage ceiling, preferably one that is easier to remove and reinstall? IRC R302.11.1 includes a list of fireblocking materials that appear to be "equivalent" to 1/2" gypsum board, but I can't find anything similar for 5/8" Type X gypsum board.
Best Answer
You could add access panels in the most useful places.
Where the wall is above, anywhere a cable turns to go up the wall would be a valid spot for an access hatch.
For a run of cable across to a ceiling fixture, you could put the cable run below the ceiling, or have an access every second space/joist.
No idea if this satisfies your code requirements, sorry you'll need to check that.
Note - it doesn't need to be fancy.... no need for hinges or latches. You could simply screw a metalised/metal-backed panel of drywall to the ceiling. May need to add some wood framing around the hole to provide a lip. The edges of your hatch would probably need some metal strip protection, as would the edge of the hole.