# Kiln dried vs air dried: which should you specify?

> Moisture content decides how timber behaves after installation. Here is how to choose between KD and AD.

Published 14 September 2026 by Borneo Woods Indonesia. Canonical: https://borneowoodsindonesia.com/blog/kiln-dried-vs-air-dried-timber/

Freshly sawn hardwood holds a lot of water. As it dries it shrinks and can move, so the drying method and the final moisture content directly affect how your product performs on site.

## Air dried (AD)

Air drying stacks timber with spacers, called stickers, so air can circulate naturally. It is gentle and cost effective, and suits structural sections and some outdoor uses where the timber will reach balance with the local climate anyway.

## Kiln dried (KD)

Kiln drying uses controlled heat and humidity to bring timber to a target moisture content, usually between 10% and 15% for exterior products and lower for interior use. It gives more predictable dimensions, reduces the risk of movement after installation and is preferred for flooring, mouldings, doors and precision profiles.

## Our recommendation

Specify KD for anything machined to a tight profile or installed indoors. AD can work for heavy sections and general construction. Tell us your target moisture content and we will confirm what is achievable for your species and size.