After a flood, drying out a house can take anywhere from several days to a few weeks depending on the weather, materials, and how quickly you start. Open windows and use fans and dehumidifiers to speed things up, but remember that hidden moisture in walls and floors can lead to mold if not handled properly. Some homeowners find it takes 3 to 4 weeks to fully dry wood framing and insulation. how long to dry out a house after a flood 35