Water Damage Drywall Repair

The Cut Line Is the Whole Job

Everything else about a water damage drywall repair is ordinary trade work. Board is hung, screwed off, taped, coated and textured the same way it always has been. The part that decides whether you are looking at this wall again next year is where the cut goes, and that is decided before any tool touches the surface.

Drywall is a gypsum core between two sheets of paper. Water entering that core does two things. It dissolves and re-deposits the surface minerals, which is the brown ring you can see, and it breaks the bond between the paper and the rock, which you cannot see at all. The second effect travels further than the first. A stain the size of a dinner plate routinely sits in the middle of a softened area two or three times as wide.

How We Find It

A pin meter puts two probes through the paper face and reads resistance between them. A pinless meter reads a shallow depth of the field without marking the surface. We use both, starting at the obviously wet spot and working outward in a grid until the numbers settle at whatever the dry parts of that same wall read, which varies house to house and season to season.

That last point matters in Riverside. In a dry inland August a sound interior wall reads very low, and anything holding water stands out sharply. After a wet week in February the baseline shifts up, so we take reference readings from an unaffected wall in the same room rather than working to a fixed number out of a manual.

The cut then goes to the nearest framing member past the wet boundary, because new board needs half a stud to land on and the old board needs the other half. That is why a repair sometimes jumps sixteen inches wider than you expected. It is not padding. It is the nearest place a screw can go.

What Comes Out With the Board

Insulation in a soaked stud bay comes out. Wet fibreglass batt slumps, holds water against the framing and does not recover its loft, and leaving it in is the most common reason a repaired wall smells for months afterwards.

Baseboard usually comes off and often goes back on. A flood cut, which is the industry term for taking the bottom section of board across a whole wall, is normally set at two feet because that is a clean line on a four foot sheet and it puts the joint where furniture hides it.

Drying Before Boarding

We do not close a cavity that is still wet. Bottom plates sitting on a slab are the slowest part to dry, particularly on the slab-on-grade tract housing across most of Riverside, where the plate is in direct contact with concrete that has taken up water of its own. Air movement across an open bay, a few days, and a re-check with the meter is the whole method. It is not complicated and it is not optional.

If the framing will not come down to a normal reading, something is still leaking and the plumbing question has not actually been answered. We would rather stop and tell you that than board over it.

Finishing to Match

New board goes in at the same thickness as what came out. Half inch on most walls, five eighths where the original was five eighths or where the assembly is rated. Taped, then coated, then sanded to a level 4 finish for a wall that is getting texture and paint, and level 5 where a smooth wall meets strong side light.

Texture is matched by sampling. Orange peel and knockdown are both spray applied and both come in a range of coarseness that a photograph will not settle. We spray a scrap, let it flash, and hold it against your wall in daylight before anything gets sprayed on the repair.

Call (951) 675-6933 and we will read the wall first.