Laminated veneer lumber
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Laminated veneer lumber (LVL) is an engineered wood product that uses multiple layers of thin wood assembled with adhesives. It is typically used for headers, beams, rimboard, and edge-forming material. LVL offers several advantages over typical milled lumber: Made in a factory under controlled specifications, it is stronger, straighter, and more uniform. Due to its composite nature, it is much less likely than conventional lumber to warp, twist, bow, or shrink.
LVL is similar in appearance to plywood without crossbands, and is typically rated by the manufacturer for elastic modulus and allowable bending stress. Common elastic moduli are 1,800,000 psi (12,000 MPa); 1,900,000 psi (13,000 MPa); and 2,000,000 psi (14,000 MPa); and common allowable bending stress values are 2,800 psi (19 MPa); and 3,000 psi (21 MPa).
A comparable material is parallel strand lumber (PSL), which is used in the same applications. Rather than being manufactured from full, parallel veneers, Parallel strand uses veneers with more defects in a more random-looking pattern. Laminated strand lumber (LSL) is another similar type that uses smaller veneers, and so is similar to oriented strand board (OSB) in appearance. Laminated veneer, parallel strand, and laminated strand all belong to the general category of structural composite lumber.
Laminated Veneer Lumber (LVL) is collectively classified as structural composite lumber. It is commonly manufactured in North America by companies that also manufacture I-joists. LVL is manufactured to sizes compatible with the depth of I-joist framing members for use as beams and headers. Additionally, some manufacturers further cut LVL into sizes for use as chord-members on I-joists. Because many LVL mills are co-located with I-joist manufacturing facilities, good jobs are being added, often to rural areas. In 2012, North American LVL manufacturers produced more than 43.4 million cubic feet (1.2 million cubic meters) of LVL in 18 different facilities, and in 2013 the production increased with more than 14%.
Because it is specifically sized to work with I-joist floor framing, residential builders and building designers like the combination of I-joist and LVL floor and roof assemblies. LVL is a highly reliable building material that provides many of the same attributes associated with large sized timbers.
Today, manufacturers are looking for ways to further improve these products, despite their already impressive environmental impacts.
- Allen, Edward and Joseph Iano. Fundamentals of Building Construction: Fourth Edition. Hoboken: John Wiley & Sons, 2004. pg. 91
- American Wood Council - http://www.awc.org/pdf/EPDs/LVL_EPD.pdf
- "North American panel output rises". Fordaq (Fordaq S.A.). 3 March 2013.
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