Why are a few fans overnight not enough?
Because fans move air without removing water. A box fan in a closed room pushes the humidity up until the air can hold no more and drying stalls; open the windows on a monsoon night and you invite damp air in. Dehumidification plus directed airflow, measured daily, is what actually finishes the job.
There is also the question of where the water is. Household fans blow across a floor, not under tile, into a wall cavity or above a ceiling, and that is where a slab-level leak puts most of its water. Those places need the material opened or air pushed into them.
The honest version of the warning: a floor that feels dry on top can still hold enough water in its bed and its baseboards to feed growth, and EPA guidance is to have wet materials dry within 24 to 48 hours.
- Air movement without dehumidification raises room humidity and then stalls
- Windows open during the monsoon bring moisture in rather than letting it out
- No household fan reaches under tile, inside a wall cavity or above a ceiling
How many days does drying take in Phoenix?
Three to five days is typical for one room where water sat on the surface and came up quickly. Wet slabs, tile mortar beds, hardwood over concrete and attic insulation take longer, and a monsoon week with high dew points slows everything down. The readings decide the end date, not the calendar.
Tile over slab is the Valley's signature case. The glazed surface sheds water, so the floor looks fine while the bed underneath holds it, and the only way to know is a meter reading checked against a dry baseline in the next room.
Heat is no substitute for equipment either. A closed room here in July is hot, which does help materials release moisture, but with nothing to remove that moisture the room simply sits humid and the numbers stop falling.
What does the daily reading log show, and why keep it?
It shows the date, the temperature and humidity in the room, which equipment ran, and moisture readings on each wet material against the dry goal. It is the evidence that drying finished properly — useful to you, to your insurer and to whoever buys the building later.
Ask for it as the work goes along rather than at the end. A log where the numbers fall steadily and then flatten at the goal is what a finished job looks like; one with gaps, or with no baseline readings at the start, is worth questioning.
Insurers commonly want the readings and photographs with a claim. The crew documents them and hands them over; what gets covered is your insurer's decision under your own policy.
Does the equipment have to run while we are living here?
In most jobs yes, and continuously. Air movers and dehumidifiers only work while they are running, so switching them off overnight adds days to the job. They are loud and warm, they want their own circuits, and the drain line or collection tank has to stay clear.
Leave the doors in the drying zone set the way the technician left them, keep the windows shut, and run the air conditioning at a steady temperature instead of letting it cycle off while the house is empty.
If the noise is unbearable in a bedroom, say so on the first visit. Equipment can often be re-sited or the zone re-sealed rather than reduced, which protects the drying times.