In an ideal world, all darkrooms would have a hard plaster or drywall ceiling. This isn't always possible, particularly in many commercial buildings. Suspended ceilings are generally terribly dusty things-both because the tiles themselves shed and because the space above them is an ideal collecting ground for dust which will eventually work itself around the tiles.
Over the years I've worked in several photo labs with suspended ceilings. They've never been entirely satisfactory. One I've seen was so bad that the technician covered the ceiling with plastic and duct tape.
Sealing a suspended tile ceiling turns out to be pretty simple. The method outlined here is modified from something I saw used to close up a clean-room style laboratory.
When the stuff dries, clean out the entire room, and move back in.
- Step 1; Take everything out of the room-the first part of this process is going to make a lot of really nasty dust.
- Step 2; Remove all drop ceiling tiles from the grid. It's a good idea to wear a dust mask and old clothes. Some ceiling tiles contain fibers that are really annoying to skin. Number partial tiles and unusually-shaped tiles so that you can get them back where they belong.
- Step 3; Take the tiles outside, and dust them off-preferably with compressed air (though NOT at 100 psi, you'll break them in half.
- Step 4; Paint both sides with a premium gloss enamel. Spraying would work best in order to get into all the little crevices. Barring that, roll the paint on with a thick-nap roller. Let tiles dry.
- Step 5; Dust off the upper side of the drop ceiling grid with a stiff paint brush.
- Step 6; Replace all the ceiling tiles.
- Step 7; Caulk the perimeter of every tile where it is held by the metal runner, using Dap tub and tile caulk. Smooth into place with a finger-maybe even run a damp rag over them.
- Step 8; Caulk the wall/ceiling joint as well.
Dale Austin firstname.lastname@example.org
All images and text copyright 1995, 1996, 1997, 1998 Dale Austin-All Rights Reserved
Last Modified 7/21/98 http://www-personal.umich.edu/~mrwizard