Seasoning Timber [top] Access

| Problem | Cause | Consequence | |--------|-------|--------------| | | Water loss causes cells to contract | Cracks, gaps, warped boards | | Distortion | Uneven shrinkage (tangential > radial) | Cupping, bowing, twisting, crooking | | Decay & Fungus | High MC (>20%) enables fungal growth | Rot, stain, musty smell, structural weakness | | Insect infestation | Moist wood attracts powderpost beetles & termites | Holes, dust, collapse | | Poor finishing | Trapped moisture repels paint/varnish | Peeling, blistering, cloudy finishes | | Fastener corrosion | Moisture + acids in wood rusts nails/screws | Staining, weakened joints | | Low strength | Green wood has lower stiffness & hardness | Failure under load |

Lower moisture content reduces the risk of fungal growth and decay. Better Workability: It is easier to saw, plane, and join. seasoning timber

Test MC weekly with pin meter. Record. Expect 1–2% MC loss per week initially, then 0.5% per week after 20% MC. Record

| Defect | Appearance | Cause | Prevention | |--------|------------|-------|-------------| | | Cracks at board ends | Too rapid drying of end grain | End seal, slower initial drying | | Surface checks | Fine cracks on face | Surface dried too fast (set stresses) | Higher humidity, lower temp | | Honeycombing | Internal cracks, not visible outside | Severe internal tension after surface set | Very slow drying schedule | | Collapse | Corrugated or sunken surface | Exceeding FSP too fast (especially in eucalyptus, redwood) | Low temp, high humidity first stage | | Casehardening | Internal tension; wood warps when re-sawn | Surface set before core dried | Conditioning (high RH) at end of cycle | | Bow | Lengthwise curve along face | Uneven drying across thickness | Proper stacking, even air flow | | Twist | Spiral distortion | Grain angle + uneven shrinkage | Weigh down stack; sticker alignment | redwood) | Low temp

| Feature | Air Seasoning | Kiln Seasoning | | :--- | :--- | :--- | | | Low | High | | Time Efficiency | Very Poor | Excellent | | Structural Integrity | High (Gentle) | Medium (Risk of stresses) | | Cost | Low | High | | Flooring Suitability | Poor (Won't get dry enough) | Essential | | Large Timber Beams | Preferred | Difficult (Risk of cracks) |

There are two primary methods of seasoning, each with distinct pros and cons.