Engineered Lumber #3: LVL

LVL or laminated veneer lumber is an engineering solution to span large distances without the need for large pieces of timber. This technology is similar to plywood in that is utilizes several thin pieces of wood glued together in various directions to create one solid and very strong beam. Unlike timber, LVL can be pieced together easily and can even be bent and formed in while making the product to conform to specific architectural applications. Although LVL was designed to be an alternative to using large and costly pieces of wood and thus often hidden within the structure of a building or house, architects have found new ways of exposing this material to express the structure and load capacity of a building.

The flexibility of LVL can be seen in the interesting spiral curvature of the Waitomo Caves Visitor Center by Architecture Workshop. The visitor center wanted an expansive structure to cover the entrance of the cave while heightening the experience of its entrance. This large-spanning wood and plastic structures was the architectural solution. These prefabricated LVL pine beams were built in a nearby factory, designed to interlock on-site to create a grid-like structure. The beams weave together making the structure of the large canopy, which was then covered by inflated ETFE pillows. LVL allows the building to be somewhat inexpensive with the ability to span a great distance and house several hundred people.

LVL is used in a very innovative way in the Metropol Parasol by ARUP in Seville, Spain. This massive mushroom-like structure is composed of more than 3000 polyurethane-covered LVL panels and houses a variety of programmatic functions including restaurants, bars, and an archaeological museum. The panels are arranged on an orthogonal grid and their individual heights are determined by how they are loaded. Diagonal steel bars reinforce the panels and help with lateral stability. Although there is no roof on the structure, the deep grid creates adequate shade and is occupied continuously throughout the year.