Carcassing timbers are those used in structural applications, such as roof joists or floor joists, framing, studwork and wall partitions. There are a range of strengths, sizes and lengths of timber available depending on your project. Carassing timber is widely available from imported or homegrown sources and is offered treated with a preservative or untreated. CLS, Canadian Lumber Standard timber is also available. This kiln-dried timber is planed and finished for more precise dimensions.