Birch Plywood

Plywood made from birch is split into 4 grades depending on the smoothness and the quality of the wood:

Grade S is the highest quality, and is naturally free from knots and blemishes. While imperfections in plywood can be repaired, this grade is altogether free from knots and damage. This makes S grade birch plywood most suitable for applications where a uniform surface is required. It is also most suitable for high-quality paints and varnishes, as there is no trapped sap or imperfections to ruin the final finish.

Grade BB is the medium grade, and whilst the wood surface has imperfections present, the wood has been refinished to give a more uniform surface. In many cases, open knots in the wood have been removed and a suitably shaped section of birch spliced into the hole. This means that the major knots (which contain sap) have been removed, reducing the incidence of sap bleed once the paint or varnish finish has been applied.

The lower WG grade allows for smaller knots in the wood to be present. However, larger knots will have been repaired, and the overall finish of the wood will have been improved to remove major imperfections. This wood is ideal for applications requiring a more 'natural' finish.

Grade C is the lowest grade for birch plywood and allows open defects and knots in the wood, without any repairs or refinishing being necessary. This is used where the strength of wood is required without the appearance being a factor. However some people value this wood for its 'rustic' appearance, choosing it specifically to give a less refined look.