Trueline

Restoration

Keeping a moisture log that proves the building dried

A drying log is only worth keeping if it can be drawn as a falling line. Most of the ways they go wrong make that impossible.

By Sam Reviewed by Gilbert Rios, Remodeling contractor, 15 years Updated 2026-09-02 8 min

What every reading needs beside it

  • Where — an identified point, marked on the wall and named the same way every visit.
  • When — date and time.
  • What material — drywall, framing, subfloor, hardwood. They dry differently and read differently.
  • What meter and what scale — %MC, a relative scale, pin or pinless.
  • The dry standard for that material in that building.

Drop any one of those and the reading becomes a number in a notebook. Drop the scale and the whole log becomes undrawable.

The mistake that ruins a log

Switching scales partway through. A relative scale on Monday and %MC on Thursday cannot be compared, cannot be plotted, and cannot be shown to an adjuster as a drying curve — because a line drawn across a scale change is not measuring anything.

Trueline keeps the scale with each reading and will not draw a curve across a change of scale. It lists the readings instead and says why. That is deliberate: a curve that quietly spans two scales is worse than no curve, because it looks like evidence.

Why the dry standard has to be recorded first

A reading is a comparison or it is nothing. Take the dry standard from unaffected material of the same type in the same building, on the same meter, before drying starts, and write it at the top of the log. Every reading afterwards is measured against it.

evidence = affected reading vs dry standard, over time
Not "17% is wet". 17% against a dry standard of 9% on the same wall type, falling to 10% over six days.

What to do at each visit

  1. Read the same points

    The ones you marked. Not near them.

  2. Read the dry standard again

    It moves with the weather. A rising dry standard explains an affected reading that stops falling.

  3. Record ambient conditions

    Temperature and relative humidity where you are taking the readings.

  4. Note what changed

    Equipment moved, added, removed. A flat day with a reason recorded is a flat day; a flat day with nothing beside it looks like nobody attended.

When to stop

When the affected materials reach the dry standard you established — not on a fixed day and not when the equipment has been in for as long as the estimate assumed. The log is what shows they did, which is why it has to be capable of being drawn.

Free download: Water damage and moisture log — a blank PDF to print, generated by the same code that produces the app’s own documents. All the templates.

Questions people ask

What is a dry standard?
A reading taken from unaffected material of the same type, in the same building, on the same meter and scale, before drying starts. It is the target the affected readings are being compared against, and without it a moisture reading has no meaning.
Can I switch moisture meters partway through a job?
Avoid it. Different meters and different scales cannot be plotted as one curve, and a log that cannot be drawn as a falling line is much harder to defend. If you must, record the change explicitly and keep the two series separate.
How many readings should a drying log have?
Enough to show a trend at the same identified points — which in practice means every visit while equipment is in place. Consistency of point and scale matters more than the raw number of readings.

Where this fits with Trueline

Trueline is an iPhone app that measures a room, takes it off, prices it from your own rate book and turns it into a proposal — with every length carrying whether it was scanned, drawn or measured, right onto the document a client reads. See how it works, or take the free templates and use them with whatever you already have.