Why does drywall have to come down after a ceiling leak?
Wet gypsum loses strength and can sag or crumble. Once it is saturated, it does not return to its original form, and the paper facing can separate from the core. Removing the wet section lets the cavity dry and prevents the board from falling.
Gypsum board is a plaster core between two sheets of paper. When it takes on water, the core softens and the paper can lift or peel. A board that has sagged may hold its shape for a while after drying, but it has lost much of its strength and its surface may be marked. Repair is usually less reliable than replacement, so the wet section is removed.
Leaving wet board in place also keeps the cavity damp. Insulation and framing above the ceiling can hold water against the board, and drying cannot reach them through a closed surface. Opening the ceiling is the way to let the cavity breathe, and it is the step that stops the wetting from spreading into the rooms beside it.
How does a crew dry a ceiling cavity?
A crew dries the cavity by removing wet insulation, opening the board where needed and moving air through the space with drying equipment. Readings on the joists and remaining insulation decide when the cavity has reached dry levels.
Drying a ceiling cavity is harder than drying a wall, because the air moves less freely and the heat of the room rises past the work. The technician sets equipment in the room below and directs air toward the opening, so that moisture is drawn out of the cavity and into the room air, which is then dehumidified.
Insulation that has taken on water is removed, because it holds moisture and keeps the joists damp. Joists and sheathing that read dry after the water is gone are kept. The crew checks them again after a set period, since a joist that looked dry at the first visit can keep giving up moisture for some time.
Can a ceiling stain be painted over?
Not until the source is fixed and the area is dry. Painting over a stain traps moisture and hides the sign that tells the homeowner the problem is not finished. The stain is left visible until the readings confirm the ceiling is dry.
A stain is a record of where water went, and painting over it removes that record. Stains that are still growing, or that return after painting, mean that water is still reaching the ceiling. The homeowner should have the source checked before any cosmetic work starts.
A stain that has dried and stayed dry for a long time can be repaired and painted once the board has been replaced and the readings are dry. The contractor who repairs the ceiling should be told where the water came from, so the new surface is not put over an active problem.
What affects the scope of a ceiling water job?
The scope depends on the area of wet board, the amount of insulation involved, the access above the ceiling and the source of the water. No figure is given here. The technician explains the scope on site, and the price is approved before work starts.
The area of wet board is the most obvious factor. A small patch below a single leak takes a short time to open and dry. A long run of ceiling wet from a pipe or a roof valley can require several cuts and a longer drying period, and each cut has to be recorded.
Access and finishes change the work as well. A ceiling with a flat attic above is easier to reach than one with tight rafters or a finished room over it. Decorative ceilings and plaster add time, because the crew has to protect and check them before opening anything.
Does a ceiling job always need a roofer?
Not always, but the source has to be found before the ceiling is closed. A roofer is needed if the roof covering is the entry point. A plumber is needed if a pipe is leaking. The cleanup crew identifies the path and records it, and the homeowner decides who makes the repair.
A ceiling stain in a room below an attic is often a roof problem. A stain below a bathroom or a pipe run is more often a plumbing problem. The technician looks at the path of the water and says which trade is likely to be needed. That opinion is recorded as a recommendation, not a diagnosis.
The cleanup crew does not do the roof or plumbing repair. Once the source has been fixed by the right contractor, the crew can confirm that the ceiling is dry and that the cavity has no remaining moisture. The homeowner should keep the roofer's or plumber's invoice with the cleanup record for the insurer.