All,
How should I go about repairing a long (5 feet) hairline crack in a plaster ceiling? Please be specific, as I have never dealt with plaster walls and ceilings before.

check your local hardware store like home depot or loews, they have products there located at the paint departement section, that repairs cracks in plaster walls, i know cuz i had to do the same thing..

Plaster repair:

Open the crack with a painter's 5-in-one tool or a "church key" can opener.....down to the wood lath........clean all dust debris and loose plaster and flat ceiling surface.........paint all surfaces including the wood lath and plaster edges with a LATEX AD-MIX(liquid at home center)........Mix the plaster patching(powder) mix with the ad-mix instead of water to a thick, stiff peanut butter consistancy..........apply with a putty/broad knife to fill the void and match the surrounding surface.........usually two coats...........force into the crack to "key" to the wood lath.........Use a large damp sponge to blend the surface to match the surrounding finish......doug

[This message has been edited by doug seibert (edited October 16, 2002).]

If you have a recurring ceiling crack on a plaster ceiling, you may have an undersupported plaster-over-gypsum lathe ceiling system.

If that is the case, your ceiling cannot be fixed with mesh tape and any type of compound or plaster alone.
It needs to be re-secured to the joists first.

This type of ceiling ( I have coined the term 'transitional ceilings')has been known to collapse unexpectedly.

I would direct you the the proper page on my website for more information:


http://estateplaster.com/TransitionalCeilings.aspx

Philip LaMachio
Estate Plaster, Inc.
Greensboro, N.C. 27403