Painting in a flood zone

[pcmeiners]

My home was hit by Sandy, had 30" of water on the 1st floor for 24 hours, in the un-finshed basement for 3 weeks. We had no power for 18 humid days, so no ability to dry out the house what so ever. When I rebuilt the house due to a fire in 1996 I used 5/8" Sheetrock and oil base primer with a latex top coat. I had the only house on the block primed with oil base, also the only house which did not have to re-do the Sheetrock. Any home which used lighter Sheetrock and latex primer lost the walls completely. The only damaged I received were two 3' seems which had a foam board against the wall for a month and a half, and a small few spots which were touched up with joint compound with no oil base primer before the top coat; since the flood I have repainted, and you would never know it was hit by salt water. Mind you the walls had a couple negatives going for them, I have cellulose in the walls and the siding had a tight Tyvex covering, both did not help with the internal moisture losses for drying. As far as mold, there my be some mold in the stud interior but I was not going to spend $30,000, ripping out walls with (possible) encapsulated mold, besides I had enough pool chlorine in the basement water to stop the mold growth in the open areas, the chlorine gas of which had to go up the studs (balloon frame).
If I were to do the Sheetrock over again in a flood prone area, I would hang the Sheetrock, prime coated it with a light oil base coat before I taped, then hit it with another coat of oil primer after the taping, before top coating with latex paint. If only I had oil base primed the tools in the basement.

 

[theoldwizard1]

Regular sheetrock (paper faced) and cellulose insulation ?

Sounds like mold city to me ! At least on the inside.

 

[Engineer61]

30" of water inside the house - I can see how an oil base primer could form a water-tight coating on the paper surface of the drywall, but unless you also primed the inside surface your drywall still absorbed a lot of water and turned to mush, now that it is dried it is crumbled inside the paper coatings and gone very soft. It will stay on the wall, but when impacted by rowdy kids or moving furniture etc you are going to start getting depressed patches and holes.
I am not going to address the mold issues you have in your cellulose insulation as it obviously is a waste of time.

 

[Kevin54]

There's no way that you can't have mold between the walls. No matter what type of insulation, no matter what type of primer, no matter what type of paint, water will gain access into the wall cavities.. Whether the water was that high 1 hour, one day or one week, you still had moisture in the wall cavity. And it doesn't matter whether it's salt water or not, any insulation in the wall cavities are going to hold moisture.. Just because you don't see black mold on the outside, doesn't mean it's not on the inside.