Teak wood is classified into 3 different grades –
Grade A, Grade B and Grade C.
Grade A – the finest grade of teak wood available, and comes from the very centre of the mature teak tree, where the wood is at its hardest ( often referred to as “the heartwood” ) and combined with its natural oils and minerals ensures that the wood lasts for many years without the need for treatment.
This dense and durable wood is free from knots and has an even golden colour – changing to a beautiful silver grey colour over time – and is easily distinguishable from other teak grades.
Its close grain and density means that it is impermeable to water and resistant to insects and woodworm, and, above all is resistant to UV light and changes in climate, and, as such, free from cracking and warping.
Grade B – often used for outdoor garden furniture, Grade B teak comes from the outer centre of the teak tree and as such does not contain as much oil and natural minerals, and is not as hard and durable as Grade A teak, and permeable to water.
Grade B teak wood therefore needs treating after a few years of use to maintain its properties, and ensure that the wood does not expand, warp and crack.
Grade C – this wood comes from the outer part of the tree ( normally referred to as the sapwood ) and is much lighter in appearance than the heartwood, and is significantly less dense. It does not contain the oils and minerals that Grade A does ( and Grade B to a lesser extent ) and should not be used outdoors, even when artificially treated, due to its likelihood to warp, and disintegrate over time.