Why measure at all

Walking a flooded building, surfaces can look dry long before they are. Concrete, drywall and wood each hold moisture differently, and a visual check cannot tell whether a wall is returning to normal or merely hiding wetness behind its paint. Measurements give a shared reference point for everyone: facility staff, restoration professionals, insurers and later repair contractors.

There are two broad types of reading. Material readings describe how much moisture sits in a surface or substrate. Air readings describe the temperature and relative humidity of the space. Both matter because moist air slows material drying, and wet materials push moisture back into the air.

Consistency is the part that is easiest to lose. Different people use different meters, take readings at different heights and skip the baseline. A one-page protocol, taped beside the log, that says where to measure, which tool to use and how long to wait before recording a value, keeps the data comparable. If a professional is taking the formal readings, ask for a copy of the data in a form you can store, so that the building's records and the contractor's records line up if questions arise later.

Common reading terms

Relative humidity
The amount of moisture in the air compared with the most it could hold at that temperature, shown as a percentage.
Moisture content
The share of a material's weight that is water, typically used for wood.
Baseline or dry standard
A reading from an unaffected area used as a reference point.
Reading point
A marked location measured repeatedly so trends can be compared.
Trend
The direction readings are moving over time, which matters more than any single number.

Making a log that others can read

  1. Mark the points

    Choose spots across the slab, walls, ceilings and stored goods, and mark them on a simple plan so they can be found again.

  2. Take a baseline

    Record a reading in a similar unaffected area for comparison.

  3. Repeat on schedule

    Measure the same points at similar times so changes reflect drying, not time of day.

  4. Note conditions

    Write down outdoor weather, open doors and equipment running.

  5. Share it

    Keep one log everyone can see so decisions are traced to numbers.

What good records usually include

Date and time
Each reading entry
Location
A named or numbered point
Material
Concrete, drywall, wood or air
Reading and device
Value plus instrument type
Observer
Who took the reading

Common questions

Can facility staff take readings?

They can log readings, but interpreting them and choosing equipment is usually work for trained professionals.

Is humidity the same in every part of a big building?

No. Corners, offices, docks and stacks of goods can differ notably, which is why multiple points are used.

General information for Commerce City, not a quote or professional advice. In an emergency, call 911.