Why bother measuring

Walk a flooded building and surfaces look dry long before they are. Concrete, drywall and wood each hold moisture differently, and your eyes can't tell a wall that's drying from one hiding water behind its paint. Readings give everyone the same reference: facility staff, restoration crews, insurers and the repair contractors who come later.

There are two kinds. Material readings say how much moisture sits in a surface or the layer beneath it. Air readings give the temperature and relative humidity of the space. You need both, because damp air slows drying and wet materials push moisture back into the air.

Consistency is the easiest thing to lose. Different people use different meters, measure at different heights and skip the baseline. Tape a one-page protocol beside the log that says where to measure, which tool to use and how long to wait before writing a number down, and the data stays comparable. If a professional takes the formal readings, ask for the data in a form you can keep, so the building's records and the contractor's line up if questions come later.

Terms on the reading sheet

Relative humidity
How much moisture the air holds compared with the most it could hold at that temperature, as a percentage.
Moisture content
The share of a material's weight that is water. Usually used for wood.
Baseline, or dry standard
A reading from an unaffected area, used as the reference point.
Reading point
A marked spot measured again and again so the trend can be compared.
Trend
The direction readings move over time. It matters more than any single number.

Building a log other people can read

  1. Mark the points

    Pick spots across the slab, walls, ceilings and stored goods, and mark them on a simple plan so anyone can find them again.

  2. Take a baseline

    Record a reading in a similar dry area to compare against.

  3. Repeat on a schedule

    Measure the same points at about the same time each day, so changes reflect drying and not the hour.

  4. Note the conditions

    Write down the outdoor weather, which doors were open and which equipment was running.

  5. Share one log

    Keep a single log everyone can see, so each decision traces back to a number.

Every entry should carry

Date and time
On every reading
Location
A named or numbered point
Material
Concrete, drywall, wood or air
Reading and device
The value and the instrument type
Observer
Who took it

Common questions

Can facility staff take the readings?

They can log them. Interpreting the readings and choosing equipment is usually work for trained professionals.

Is the humidity the same everywhere in a big building?

No. Corners, offices, docks and stacks of goods can differ a lot, which is why the log uses many points.

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