What Is Shiplap Siding?

Shiplap siding is a type of wooden siding made from board planks. It gets its name from the fact that the specific construction technique has been used for centuries to build different kinds of boats, perhaps even from the time of the Vikings in Scandinavia.

Shiplap siding differs from board and batten siding and other types of wooden siding alternatives, mainly by preparing each wooden plank or board used. Each wooden plank or board has a groove cut alongside the board during the prep process, which allows each plank to overlap slightly with the next one. The overlapping effect from one piece to the next essentially seals the siding. It makes for a solid wall face without any creases where air or moisture can enter. In contrast, board and batten siding covers the space between each plank with a separate piece of wood. With shiplap, the overlapping design of the siding allows for a smooth exterior or interior as each part fits neatly together. Most shiplap siding is designed to be installed horizontally. However, it is possible to cut the tongue and groove cuts vertically as well.

When shiplap siding is cut and installed correctly, the tongue and groove interlocking system creates a seal that protects against wind, rain, and moisture. Space where the wood connects also allows the wood to naturally expand and contract with the seasons and as the wood ages. 

This characteristic means that the lumber on your interior or exterior siding will be less susceptible to buckling and cracking. Some types of wood siding will shrink or crack over time, thus potentially allowing jeopardizing the building envelope of your home. On the other hand, Shiplap siding is generally better suited to enable the wood to settle naturally over time. This way, the energy efficiency and thermal performance of your home are not compromised.