1. Why dried timber can regain moisture
Wood continues exchanging moisture with the surrounding air after drying. It can gain or lose moisture and change dimensions. “Kiln dried” describes a process, not a promise that moisture will remain unchanged in any warehouse. OSU explains the underlying relationship between wood and atmospheric moisture.[1]
MC is timber moisture content; RH is the relative humidity of the air. A warehouse RH sensor does not replace a timber moisture meter. Nor does a report of humid weather establish that every board in a pack is outside specification.
For kiln-dried acacia timber, agree the acceptable MC range, inspection point and next manufacturing operation. A below-12% target used for one stake product must not become the default requirement for every board or component.
2. Hand over the records with the timber
Identify who receives each batch from drying and where it will be stored. The handover should establish the batch, sizes, inspection status and destination. “Out of the kiln” does not automatically mean “accepted for dispatch.”
- Match batch and pack identifiers to species, dimensions and quantity.
- Label the status: accepted, awaiting inspection or requiring further assessment.
- Transfer the inspection method, instrument, sampling locations, time and operator; retain individual readings rather than just an average.
- Allocate a storage position and preserve traceability when packs are split or regrouped.
Keep wet or unverified stock identifiable separately from accepted dried stock. Kiln operation and end-of-cycle decisions belong in the timber drying procedure; this guide does not provide kiln-opening instructions or a redrying schedule.
3. Inspect the storage location before receiving a batch
The USDA Wood Handbook distinguishes storage requirements by product and intended use. It discusses supports above the floor, protection from water and controlled humidity where required. Requirements for structural stock should not be applied automatically to machined furniture components.[2]
| Area | Check | Record |
|---|---|---|
| Roof, walls and doors | Leaks, wind-driven rain and water paths | Repairs or positions temporarily excluded from use |
| Floor and supports | Standing water, damp/dirty supports and stability | Location, support arrangement and inspection owner |
| Stacks | Support, straps, labels and inspection access | Any departure from the approved stacking arrangement |
| Nearby operations | Wet stock, washing or other moisture sources | Separation measures and receiving conditions |
| Monitoring equipment | Representative sensor positions and equipment checks | Instrument identifiers and review dates |
Determine support spacing, stack height and handling routes from loading, timber stiffness and the site's safe handling plan. A roofed shed is not necessarily a humidity-controlled store. If the store cannot meet the agreed conditions, review the storage or delivery plan instead of changing the label to fit a new reading.
4. Plan moisture checks that can be compared
Define who measures, where, at which events, and who decides what to do with an abnormal result. Receiving into storage, packing, dispatch and a wetting incident are useful planning points. Routine intervals should reflect storage duration, conditions and the order requirements.
Follow the meter manufacturer's instructions, including species and temperature corrections where applicable. USDA notes that electrical measurements depend on the instrument, measuring position and moisture gradients; a surface reading does not automatically represent the core or the entire pack.[2] See the timber moisture guide.
- Keep individual readings linked to sample locations.
- Flag uncertain results and inspect further under the agreed sampling plan; do not replace unfavourable readings by choosing better-looking boards.
- Record changes in instruments or settings.
- Check the instrument and method when results conflict, and use an appropriate reference method if necessary.
Do not operate ventilation simply because outside air feels breezy. Ventilation and dehumidification serve different purposes. The operating plan must consider indoor/outdoor conditions and the installed equipment; no single RH setting or fan schedule is specified here.
5. Pack for the actual journey
Before packing, check the batch status, wrapping, supports, straps and labels against the delivery specification. Link the pre-packing inspection to its measurement record rather than using “dried” as the only release criterion.
Sealing does not remove water already present in timber or packaging. Leaving a pack open does not protect it from rain either. Define the packaging purpose, the condition of the goods before closure and the response to damage. Adding film or desiccant is not a universal solution.
Inspect the vehicle or container before loading for water, leakage, contact surfaces and consignee requirements. Retain photographs with the batch record. If droplets or damp areas are found, document and investigate them before proceeding. Agree custody, the delivery point and the process for nonconforming goods. Drying does not replace separate export or heat-treatment documentation.
6. Release the goods and records together
- Pack identifiers, species, sizes and quantities match the dispatch documents.
- MC results identify method, time, sample locations and acceptance criteria.
- Checks cover appearance, cracks, distortion and damp areas as required by the order.
- Wrapping, straps, labels and supports follow the approved packing plan.
- The vehicle and handover arrangements have been checked within the responsible party's scope.
- Open issues have an authorised decision; unaccepted goods remain distinguishable.
Assign an inspector and a conclusion to each check. A blank field means missing information, not acceptance. Review the inspection plan after extended storage, leaks, wetting, unpacking or relocation; an old record cannot establish the present state of every pack.
7. Respond to abnormal moisture without losing the evidence
LEFAMI proposes four record-management steps: identify, verify, decide and retain the result. This is not a chemical mould-treatment procedure or a redrying schedule.
- Identify the affected pack, location, time and visible signs; photograph and hold the relevant stock separately.
- Compare drying and storage history, previous readings, packaging and the current measurement method.
- Have the responsible person decide on further inspection, revised storage, reprocessing or customer consultation before release.
- Retain the original readings, decision maker, action and reassessment date.
Do not improvise chemical mixtures, increase kiln temperatures or conceal a suspect pack for dispatch. Any treatment requires an assessed procedure appropriate to the product and workplace.
8. Worked example: weight gain is not extra dry wood
On a dry basis, MC equals water mass divided by oven-dry wood mass, multiplied by 100%. In a hypothetical example with 100 kg of unchanged dry wood, 12% MC gives 112 kg total mass; 16% MC gives 116 kg. The 4 kg difference is water within that model.
A real pack also includes straps, wrapping, supports and weighing uncertainty, and its contents may change. One gross weight does not establish the MC of the whole pack. The example predicts neither a moisture uptake rate nor an acceptance limit.
9. Storage log template
Use a row for a defined inspection of a pack or sample group. Copy this table into Excel if useful; expand it without losing batch identifiers. Blank entries below are placeholders, not LEFAMI production data.
| Field | Entry | Note |
|---|---|---|
| Date/time and inspector | … | Actual inspection event |
| Batch / pack ID | … | Link drying and receiving records |
| Storage position / packaging | … | Changes since the previous check |
| Air temperature / RH | … °C / … % | Sensor ID and location |
| MC / measurement record | … % / … | Samples, instrument and settings |
| Observations / photos | … | State what was checked |
| Conclusion / decision owner | … | Accepted, pending or requiring action |
| Action / next review | … | Preserve the earlier results |
10. Frequently asked questions
Can timber dried below 12% be stored outdoors?
A single MC result does not approve outdoor storage. Review protection from rain, packaging, duration and the requirements after storage.
Should timber be sealed immediately after leaving the kiln?
Not on timing alone. Follow an assessed handover and packing procedure; investigate unverified temperature/moisture conditions or water in the wrapping first.
How often should MC be checked again?
Set intervals for the goods and storage conditions, with event-triggered reviews after leaks, wetting, unpacking, relocation or material delivery delays. There is no universal number of days.
Can the best reading release the entire pack?
No. Use the agreed sampling plan, retain the range of results and state the scope of the conclusion.
What should a buyer include in an inquiry?
Finished dimensions, end use, acceptable MC, inspection method, quantity, packaging and destination. Use the kiln-dried timber inquiry form.
Technical sources and editorial scope
- OSU Extension — Wood and Moisture Relationships.
- USDA Wood Handbook (2021), Chapter 13: moisture measurement and transit/storage control; printed pages 13–1 to 13–3 and 13–15 to 13–16.
Sources support technical concepts. Checklists, the log and record workflow are LEFAMI editorial proposals, not an acceptance standard validated for every workshop. Numerical examples are hypothetical. Confirm actual requirements for the species, equipment, store and contract.