Understanding Kiln Dried After Treatment (KDAT) Lumber

Understanding Kiln Dried After Treatment (KDAT) Lumber

BarrierBoss is excited to announce we have made the switch to KDAT lumber. Customers can still expect the same beautiful honey-brown colour our treated lumber has always had, as well as celebrate a wood whose processing allows it to withstand weather even better.

The Process Behind the Product

Traditional pressure-treated lumber follows a straightforward path: wood gets immersed in liquid preservatives within a pressure chamber, forcing chemicals deep into the wood fibers. But KDAT lumber takes this process one crucial step further.

After pressure treatment with chemicals, KDAT lumber enters a controlled kiln environment. Here, carefully managed temperatures and strategic stacking create optimal airflow between boards, ensuring uniform drying throughout. This additional step removes up to 80% of the moisture content—a dramatic reduction that transforms the lumber's performance characteristics.

While conventional "green" or "wet" treated lumber can take 8 months to a year to naturally dry (often causing significant problems during this extended period), KDAT lumber emerges from the kiln already stabilized and ready for immediate use.

Why KDAT Outperforms Traditional Treated Lumber

The benefits of this enhanced drying process extend far beyond simple moisture reduction:

Immediate Application Readiness: Paint, stain, or seal your project right away—no waiting periods required.

Dimensional Stability: The controlled drying process dramatically reduces cupping, warping, checking, and shrinking that plague traditional treated lumber.

Superior Workability: Handling, cutting, and planing become significantly easier compared to waterlogged alternatives.

Reduced Weight: Without excess moisture, KDAT lumber weighs considerably less than its "wet" counterparts.

Enhanced Fastener Performance: Both nails and screws achieve superior holding power in the drier wood.

Tool-Friendly Properties: Drilling and sawing operations proceed smoothly without the resistance common in green lumber.

Critical Applications Where KDAT Excels

Decking Solutions

Perhaps nowhere is KDAT lumber more valuable than in composite decking applications. Traditional pressure-treated substructure creates ongoing problems as joists shrink, cup, and warp during their natural 8-month drying period. This movement causes deck boards to twist and warp, leading to customer complaints and expensive callbacks.

KDAT lumber eliminates these issues by arriving already stabilised, with minimal tendency toward shrinking, warping, or cupping.

Versatile Project Applications

KD Lumber can be used comprehensively in a wide variety of cases:

• Deck construction (boards, rails, joists, posts)
• Pergola frames
• Fencing systems
• Marine construction and boardwalks
• Flatbed trailer construction
• Storage shed framing

Chemical Treatment Overview

Micronized Copper Azole (MCA): The current preferred treatment, offering versatility across above-ground, ground contact, and freshwater applications while providing a more environmentally conscious copper-based preservation system.

Maintenance Considerations

Both KDAT and traditional treated lumber require periodic maintenance—typically sanding, cleaning, and re-staining every two to five years, depending on climate exposure and stain quality. However, KDAT's superior dimensional stability means fewer structural issues and repairs over time.

Economic Analysis

KDAT lumber can go for 15-25% over traditional wet treated lumber, reflecting its specialty processing requirements. This pricing is extremely favourable due to its delivery of significantly better performance than commodity green lumber.

The investment pays dividends through reduced callbacks, fewer structural problems, and immediate project completion capabilities—factors that often justify the initial cost difference for both contractors and property owners.