MANUFACTURING / JAPAN SOURCING
Timber moisture content: record when, where and how it was measured
For dried sugi interior components, a dispatch moisture figure is not a guarantee of the condition after arrival. Match each reading to the lot, sampling location, method and storage history before comparing it.
Two identical percentages may describe different checks
Imagine two offers for dried sugi strips intended for interior joinery. Both say “12% moisture content”. One figure is a dispatch meter reading at an unspecified location; the other is a sample result taken after storage. These are fictional records, not a recommended target or evidence that either offer meets the buyer’s needs.
Ask what object, time and method the number describes. The US Forest Service’s Wood Handbook abstract explains the importance of drying, handling and storage as moisture moves toward equilibrium with the surrounding air.[2] “Kiln dried” does not fill in the missing inspection record.
- 1Identify each piece and its measurement locations
- 2Keep each reading with its time, method, instrument and settings
- 3Relate the dispatch and receipt records to handling and storage history
Illustrative linked records: A is the piece identifier, D the dispatch check and R the receipt check. Marks are example locations, not a sampling plan; no pin depth or moisture acceptance limit is prescribed.
Keep the measurement method with the result
Oregon State University Extension distinguishes oven-dry measurement from electrical meters, including pin and dielectric types, and describes factors affecting readings.[1] A handheld reading and an oven-dry result should not be treated as interchangeable solely because both are percentages.
Kett’s HM-540 product specification, for example, identifies high-frequency capacitance measurement and model-specific conditions.[3] Ask which meter and manual apply to your material, how the relevant species/density, thickness and temperature conditions are handled, and what instrument checks are recorded. Do not borrow accuracy claims from another model or reference sample.
Agree how the pieces and locations will be selected
Record the lot and piece identifiers, where on each piece the reading is taken, and the measurement depth or sensing arrangement where relevant. The agreed method should explain how the selected pieces and locations represent the delivery, including how variation will be retained.
For this sugi-strip enquiry, ask the supplier to propose a sampling and measurement plan appropriate to the size, material and intended use. Keep individual results and the range needed by that plan, not just an unexplained average. This article does not prescribe a sample count or a standard pin depth.
| Record | Keep with the result | Resolve before acceptance |
|---|---|---|
| Material | Keep with the resultSpecies, product, dimensions, lot and piece references | Resolve before acceptanceAre the dispatch and receipt checks about the same material? |
| Method | Keep with the resultInstrument/method, relevant settings and instrument check | Resolve before acceptanceAre methods compatible; how are differences resolved? |
| Location | Keep with the resultSelected pieces, measurement positions and sensing depth/arrangement | Resolve before acceptanceDoes the agreed plan address variation in this delivery? |
| Time and conditions | Keep with the resultDate, dispatch/receipt stage and relevant temperature/storage information | Resolve before acceptanceWas the wood exposed to different handling or storage? |
| Decision | Keep with the resultAgreed criteria, exceptions and acceptance owner | Resolve before acceptanceWhich results need investigation or a reference measurement? |
Separate dispatch, receipt and use conditions
OSU explains that dried wood can continue to gain or lose moisture and change dimensions.[1] Keep the intended indoor environment in the enquiry and agree how transport, packing and storage will protect the material and be recorded. A dispatch value alone does not predict the exact dimensions after a different storage history.
Decide when receipt inspection will occur, where the material will be stored before use, and who reviews any conditioning needed before machining or installation. Avoid inventing a universal acclimation period. If the received reading differs, check material identity, method and conditions before assigning a cause.
Define the response to a disputed reading
Set the moisture criteria and measurement plan for this product and use with the responsible technical parties. Agree what happens if results differ: retain the identified material, review the records, and use an agreed reference method or specialist assessment where needed.
Moisture content is one part of the specification. Keep dimensions, grade, defects, finishing and intended use as separate requirements. A moisture result alone does not approve structural suitability, phytosanitary conditions or import eligibility; those need the relevant product and destination evidence.
Questions to send your supplier
Open supplier questions
Product: dried sugi strips for interior joinery Dimensions, grade, quantity, destination and intended environment: Please state the proposed moisture criteria and acceptance stage. Provide the lot/piece identification, sampling locations and method/instrument with relevant settings and checks. How will individual readings and variation be recorded? Please distinguish dispatch, receipt and any pre-use conditioning checks. Confirm packing/storage responsibilities and the agreed response if results differ. Required date:
Sources
- Oregon State University Extension — Wood and moisture relationships
Public descriptions of moisture exchange and measurement methods/factors. Its example moisture targets and species tables are not adopted as this product’s requirements.
- US Forest Service — Wood Handbook chapter 13, 2021
Official chapter abstract on drying, handling, storage and moisture control; not used as a product-specific moisture acceptance limit.
- Kett — Wood Moisture Tester HM-540
Manufacturer specification identifies high-frequency capacitance measurement and model-specific qualifications. No meter is selected or calibration verified.