All Industry Standard Sizes All commercial doors come at a thickness of 1-3/4”.

Besides color, you can use the wood grain to identify which type of wood species you have. Some types of wood, such as alder and birch, are known for the knots in their grain. On the other hand, woods like poplar and cherry have few knots. Besides knots, you'll also want to look at the lines or rings in the grain.

Commercial Door Core Types Structural Composite Lumber (SCL) Core: Strands of different types of small-diameter hardwood trees combined with special resins. It is more durable and heavier than particleboard. Particleboard Core: Ground-up raw wood glued together. It is durable, low cost, and widely available.

MDF. Manufactured using recycled wood fibers, MDF is an extremely common, widely available, and relatively affordable option for interior door materials compared to solid wood. These doors won't warp like solid wood and will not have a wood grain-style finish. They are also very easy to paint and maintain.