LVL beams have become a popular choice for structural framing due to their strength, consistency and span-capability. But when it comes to outdoor use, many ask: Can LVL beams be used outside? The answer is yes, but with important considerations. Not all LVL beams are designed for direct outdoor exposure; the material must be properly treated, installed and protected. Treated LVL products are now suitable for above-ground exterior use, provided they meet the right specifications and exposure conditions.
Using laminated LVL beams in construction brings several benefits:
High strength and stiffness: LVL is made by bonding thin wood veneers in a factory setting, resulting in beams with far more predictable strength and load capacity compared to many solid sawn timbers.
Dimensional stability: Since the veneers are controlled and defects are minimized, LVL beams resist warping, twisting, shrinking or swelling much better than typical lumber when used in framing.
Long spans and fewer supports: Because LVL can be manufactured in long continuous lengths and large cross-sections, exterior structures like decks and porches can achieve wider spans with fewer posts or beams.
Consistency and quality control: Each construction LVL beam is engineered, graded and stamped for performance, meaning fewer surprises on job-site and reliable performance for outdoor structural use. With manufacturing standards, certification, and quality control (like Fuqing lists certifications including FSC, PEFC, AS/NZS 4357) the structural performance is documented and reliable.
Material efficiency & sustainability: LVL uses veneers from smaller trees and less waste compared to large solid timbers, placing it as a more sustainable structural choice.
When properly treated for outdoor exposure, LVL beams are used in a variety of exterior structural settings:
Deck beams and joists: Many modern decks use treated LVL beams instead of traditional treated lumber for the main load-carrying member because of higher strength and span capability.
Exterior headers and lintels: Above large windows or doors on the exterior of a building, LVL beam can carry heavy loads while maintaining structural integrity.
Roof framing and overhangs: For porches, porticos or roof extensions, LVL beam exterior use offers a strong, straight member able to resist outdoor conditions.
Posts, beams and carport framing: Treated LVL beams can be used for outdoor columns or framing where exposure to elements is higher.
Semi-exposed structural elements: Where architectural design leaves some timber exposed to the elements, properly protected LVL beams can function both structurally and visually.
Even treated LVL beams require good protection and detailing when used outside. Here are key strategies to ensure durability and performance:
Choose an LVL product that is specifically treated for exterior exposure. For example, some LVL are manufactured with preservative treatments during production, like pressure-treated LVL and site-resistant overlays, that allow them to be used above ground outdoors. [1]
After installation, protect surfaces with a high quality exterior sealant, paint, or stain. Ensure that end grain and cut edges are sealed immediately to prevent moisture ingress. Many users note that LVL exposed during construction without covering may warp or swell at the ends.
Ensure the beam is installed with adequate drainage and air circulation around it, so water does not sit and cause prolonged moisture exposure. Support on properly designed bearings or posts is important.
Even treated LVL should avoid direct contact with soil and be sheltered from direct rainfall where possible. Use suitable supports, flashings and protect the top faces from pooling water.
Don’t treat a standard LVL like an exterior-rated one. Be sure the beam type is rated for exterior use, follow splice limits, fastener schedules, limiting notches and cut-outs. Some manufacturers specifically say standard LVL is not designed for un-protected outdoor use. [2]
LVL beams can absolutely be used outside, provided you choose the right product, protect it properly, and follow correct installation procedures. Their advantages in strength, stability and span make them an excellent choice for exterior structures such as decks, overhangs and exterior headers. With lifetime-tested treatment systems, engineered LVL is no longer confined to interior framing. If designed and installed correctly, exterior LVL beams deliver both performance and longevity in demanding environments.
Not inherently. LVL beams are engineered for strength and consistency, but unless they are specifically treated for exterior use (preservatives, coatings) and properly installed, they are not waterproof. Some treated LVL products include water-resistant overlays or preservative treatments designed for outdoor environments.
Fuqing product features include high-grade adhesives (phenol formaldehyde), moisture content control (8-15%), treatment to H2S pest standard, certifications (FSC, PEFC, AS/NZS 4357), long lengths up to 12 m, and manufacturing processes aimed at stability (see 5-7 day full conditioning cycle).
When correctly specified, treated LVL beams used in above ground exposure can last decades. Some treated systems come with 25-year warranties for outdoor use in decks and exterior framing. [3]
No. You must ensure the LVL is rated for exterior use. Standard interior-grade LVL is intended for dry indoor framing and may not hold up to weather, moisture and outdoor exposure.
Extra care is needed: ensure proper flashings, cover or coat promptly, protect cut ends, provide drainage and ventilation, use approved fasteners and treat certain connections to resist corrosion or moisture. Follow manufacturer’s specs for outdoor use.
Yes. Even exterior-rated LVL beams benefit from surface coatings, weatherproofing and detailing to maximize lifespan. The treatment raises durability but does not replace good design and protection.
References:
[1] https://shepleywood.com/news/pwt-treated-lvl-for-exterior-use
[2] https://www.finehomebuilding.com/forum/lvl-beam-exposed-to-the-weather
[3] https://shepleywood.com/news/pwt-treated-lvl-for-exterior-use
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