The Strength of NLT
NLT gets its strength and durability from the nails that fasten individual dimension lumber, stacked on edge, into a single structural element. Applications for NLT include flooring, decking, roofing and walls, as well as elevator and stair shafts. Because NLT is made of wood, it offers a consistent and attractive appearance for decorative or exposed-to-view applications.
Its revival is due in large part to its domestic availability. The mass timber product does not require a dedicated manufacturing facility, compared with others like cross-laminated timber (CLT). And it can be fabricated with readily available dimension lumber, allowing project teams and manufacturers to use locally sourced materials.
How NLT Can Be Used
NLT is created by placing dimension lumber on edge and mechanically fastening the individual laminations together with nails or screws. Nominal 2x, 3x and 4x thicknesses and 4-inch to 12-inch widths are typically used to create NLT panels. The addition of plywood or oriented strand board sheathing on one face of the panel provides in-plane shear capacity, allowing NLT to be used as a shear wall or structural diaphragm.
Architects like NLT because it can be used to create monolithic slab panels that support a range of structural and design needs, including curves and cantilevers. The International Building Code (IBC) recognizes NLT as code-compliant for buildings with varying heights, areas and occupancies, allowing for Type III, Type IV or Type V construction.
NLT does not require a dedicated manufacturing facility, and it can be fabricated with readily available dimension lumber.
Prescriptive requirements for fire and life safety performance in IBC Section 101.3 are based on construction type, which depends on use and occupancy classification, as well as building height and area. NLT is listed as a prescriptive heavy timber assembly in Type IV construction. However, the IBC allows NLT in all types of construction.
Designers increasingly go beyond prescriptive parameters when specifying NLT in buildings. Section 104.11 of the IBC provides a performance-based path for code approval. For example, designers may consider enhancing certain fire safety features in order to use NLT in areas not prescribed by code in Type I or II construction.
The Hudson | Mackenzie Architects | Christian Columbres Photography
The Hudson Case Study: Nail laminated Timber in Modern Office Space
Located in the heart of historic downtown Vancouver, WA, the Hudson’s floor and roof system features 2×4 and 2×6 nail-laminated timber (NLT) decking. Its exposed wood ceilings add aesthetic warmth while absorbing noise. Floors are topped with reinforced concrete for added durability. Read more.
Download the NLT U.S. Design and Construction Guide here.
Download the NLT Canadian Design and Construction Guide here.