You’ve Heard Me Say “The Reading Is 28%” — Here’s What That Means
During every restoration job I manage, I share moisture readings with the homeowner. It’s part of the process. But I’ve noticed that the numbers mean more when you understand what they’re actually measuring — not just that “lower is better.”
I’m Phil Sheridan. I own 4D Restoration in Edmond, Oklahoma. Here’s a quick explanation of the tools I use, what the numbers represent, and what they tell us about your house.
The Two Types of Moisture Meters
Pin-Type Meter
Two metal probes (pins) are pushed into the material surface. The meter sends a small electrical current between the pins and measures the resistance. Wet materials conduct electricity better than dry materials, so lower resistance = higher moisture content.
Best for: Precise readings in wood, drywall, and other porous materials. The reading tells you the moisture content as a percentage of the material’s dry weight.
When I say “this stud is reading 22%,” I mean: this piece of wood currently contains water equal to 22% of its dry weight.
Pinless (Radio Frequency) Meter
A sensor pad pressed against the surface sends a radio frequency signal into the material. The signal’s behavior changes when it encounters moisture. No penetration required — the reading happens through the surface.
Best for: Scanning large areas quickly without damaging surfaces. Identifying moisture behind intact drywall, under flooring, or in areas where holes aren’t practical.
Limitation: Pinless meters give a relative reading (usually 0–100 on a reference scale) rather than a true percentage. They’re excellent for mapping the extent of moisture but less precise for confirming final dryness. I typically scan with pinless first, then confirm with pin-type.
What “Normal” Looks Like
Every building material has a baseline moisture content — the level it naturally maintains in your home’s environment:
| Material | Normal Moisture Content | Drying Target |
|---|---|---|
| Softwood framing (2x4, studs) | 8–12% | Below 15% |
| Hardwood flooring | 6–9% | Match unaffected area ±2% |
| Drywall (gypsum board) | Less than 1% | Less than 1% (pin) |
| OSB subfloor | 8–12% | Below 15% |
| Plywood subfloor | 8–12% | Below 15% |
| Concrete slab | Varies | Below 75% RH (in-situ probe) |
The critical concept: “dry” is not zero. Wood always contains some moisture. Drywall always contains a small amount. The target isn’t to reach 0% — it’s to return the affected material to its normal equilibrium moisture content for the conditions in your house.
How I Determine the Target
This is the part most homeowners don’t know about:
I don’t dry your walls to a fixed number. I dry them to match the unaffected areas of your house.
On Day 1 of every job, I take readings in the affected area AND in an unaffected area of the same home — same material, same conditions. That unaffected reading becomes the target.
Example:
- Unaffected hallway wall stud: 10%
- Affected living room wall stud: 34%
- Target: Bring the living room stud down to 10% (matching the hallway)
This method accounts for Oklahoma’s ambient humidity, your home’s specific construction, and the natural variation between materials. A fixed target of “15%” might be too generous for a home where the unaffected reading is 8%, or it might be impossible to achieve in a home where the baseline is already 14% due to seasonal humidity.
Reading the Drying Curve
Every day during drying, I take readings at the same locations. This creates a drying curve — a progression that shows how quickly moisture is leaving the material.
A healthy drying curve looks like this:
| Day | Reading | Trend |
|---|---|---|
| Day 1 | 34% | — |
| Day 2 | 26% | ↓ 8 points — strong initial drop |
| Day 3 | 19% | ↓ 7 points — consistent decline |
| Day 4 | 14% | ↓ 5 points — approaching target |
| Day 5 | 11% | ↓ 3 points — at target (unaffected area = 10%) |
The curve flattens as you approach the target — this is normal. The steepest drops happen in the first 24–48 hours when surface moisture evaporates quickly. The final few percentage points take longer because the remaining moisture is deeper in the material’s cellular structure.
When the curve stalls — readings stay flat for 24+ hours — something is wrong. Either:
- There’s a secondary moisture source (continuing leak, condensation from outside)
- Moisture is trapped behind a barrier (paint film, vinyl flooring, sealed surface)
- Equipment needs repositioning to target a different area
A stall is actionable information, not a problem by itself. I investigate, identify the cause, and adjust. This is why daily monitoring matters — the curve tells us whether the drying plan is working.
What Your Restoration Company Should Be Showing You
You should see moisture readings at every monitoring visit. Specifically:
- Starting readings — documented on Day 1 with photos
- Daily progress readings — at the same measurement points, showing the drying curve
- Unaffected baseline — so you can see what the target is
- Final clearance readings — confirming the structure reached target before equipment is pulled
If your restoration company isn’t sharing readings, you have no way to verify:
- Whether the equipment is actually working
- Whether the timeline they’re quoting is accurate
- Whether pulling equipment on Day 3 is appropriate (maybe it is, maybe it isn’t)
- Whether the structure was actually dry when they declared the job complete
The readings aren’t proprietary. They’re the evidence that proves the work was done correctly. Any legitimate restoration company will share them without hesitation.
The Reading That Matters Most
Of all the readings I take, the one homeowners should pay the most attention to is the wall cavity reading.
Floors feel wet and you can see them. Baseboards swell and you can see them. But wall cavities are enclosed. The moisture hiding behind your drywall is invisible and unfelt. It’s also the moisture most likely to cause problems if it’s not addressed — because enclosed cavities have poor airflow, warm temperatures, and cellulose food sources (drywall paper, wood framing) that mold needs.
When I report that the wall cavity has dropped from 32% to 14%, that’s the reading that tells you the job is on track. The surface readings are just the visible indicator — the cavity reading is the structural truth.
Ask to See the Data
Next time a restoration company is in your home, ask: “Can I see the moisture readings?” If they say yes and show you daily progression with baseline comparisons, you’re in good hands. If they can’t produce them, ask why.
If you’re dealing with water damage and want an assessment with real data — call 405-896-9088.
Phil Sheridan. Owner, 4D Restoration. IICRC Certified. 405-896-9088.