Preservative Treatments Approved for Trus Joist Engineered Wood Products

TECHNICAL #TJ-1020 RESOURCE SHEET

Preservative Treatments Approved for Trus Joist® Engineered Wood Products

Wood is naturally susceptible to attack by wood-destroying decay fungi and termites. Therefore, it requires preservative treatment under certain end-use conditions, including some dry-service applications where wood-destroying termites are present or where the wood comes in direct contact with concrete or masonry.

This technical resource sheet explains common applications and end-use conditions that require preservative-treated products, and describes the current preservative treatments used to protect Trus Joist® structural composite lumber products—including Parallam® PSL, TimberStrand® LSL, Microllam® LVL, and TJI® joists—against fungal decay and termites. Contact your Weyerhaeuser representative if you have any questions that are not covered by this resource sheet.

Use Categories and Service Levels AWPA categories into Service Levels (SL) The American Wood Protection Association's based on anticipated in-service moisture (AWPA) Use Category System (UCS) content ranges. A design professional characterizes the end-use conditions must determine the appropriate wet or dry that require treated wood products. service conditions for the application. The Weyerhaeuser has simplified product following table can be used to determine design and specification by grouping these the applicable Service Level.

Service Levels and AWPA Use Category Descriptions by Application AWPA Parallam® Plus PSL is the only Service Use Application Environment Products and Typical End Uses Level Category Trus Joist® product meeting Dry, aboveground; TimberStrand® LSL, TJI® joists, the requirements for exterior, continuously protected from weather Microllam® LVL, Parallam® PSL, exposed applications. or other sources of moisture and Parallam® Plus PSL products UC1 Trus Joist® products treated with TRU-CORE® I or Dry, but risk of insect TRIB II® (see compatibility table on following page); SL 1 ® ® MC ≤ 16% (termite) damage StrandGuard TimberStrand LSL, and Parallam® Plus PSL products

Damp, aboveground; protected from Trus Joist® products treated with TRU-CORE® I; weather but subject to occasional ® UC2 and StrandGuard TimberStrand® LSL, sources of moisture or direct contact ® with concrete or masonry and Parallam Plus PSL products Aboveground, exterior construction Parallam® Plus PSL beams, headers, UC3A(1) with coating or other design feature SL 2 that prevents prolonged wetting and columns MC > 16% Aboveground, exterior construction; and ≤ 28% Parallam® Plus PSL beams, headers, UC3B exposed to all weather cycles; prolonged wetting and columns Typical ground or fresh water contact; Parallam® Plus PSL beams, headers, and columns; UC4A exposed to all weather cycles in aboveground applications only SL 3 MC > 28% High decay potential, ground contact, UC4B and saltwater splash applications; Parallam® Plus PSL columns exposed to all weather cycles

(1) May be defined as Service Level 1 if dry-service conditions (16% maximum moisture content (MC)) exist. Preservative Treatments Approved for Trus Joist® Engineered Wood Products

Fungal Decay and Termite Treatments Compatible with Trus Joist® Products Based on End Use

Property Corrosion Resistant Service Product Common End Uses Approved Treaters Treatment Reduction Hardware Required Level Availability

Parallam® Plus PSL Beams and columns Culpeper Wood Preservers Copper azole or CCA Yes Yes SL 1–3 U.S.(1) Interior TRIB II® No Parallam® PSL Honolulu Wood Treating, LLC No SL 1 Hawaii beams and columns TRU-CORE® I Yes ® Interior beams, sill plate, U.S. and Canada StrandGuard Treated during manufacture Zinc borate No No SL 1 TimberStrand® LSL rim board, and wall framing including Hawaii Interior sill plate, truss chords, rim board, ® Honolulu Wood Treating, LLC ® TimberStrand LSL wall framing, columns, TRIB II Yes No SL 1 Hawaii beams, and headers TRIB II® No Microllam® LVL Interior beams and headers Honolulu Wood Treating, LLC No SL 1 Hawaii TRU-CORE® I Yes TRIB II® TJI® Joists Interior floor and roof joists Honolulu Wood Treating, LLC No No SL 1 Hawaii TRU-CORE® I (1) Limited availability in the western U.S. • Contact information for approved treating partners listed on page 4.

Preservative Treatment Descriptions applications are necessarily a wet-service (e.g., TRIB II®), allow sufficient time Wood preservative treatments commonly condition and, conversely, not all interior for the solvent to dissipate, or provide consist of a fungicide and/or insecticide that applications are a dry-service condition. adequate ventilation, before closing in is either applied during the manufacturing the structure. process, or applied later at a treater using a Considerations for Treated Applications commercial pressure-treating process. For applications with treated products Hardware Recommendations: Due several issues should be considered to help to the high moisture content typically StrandGuard® TimberStrand® LSL and ensure a structure will perform properly. present where Parallam® Plus PSL is Parallam® Plus PSL are stocked at Improperly detailed column bases and used, it is very important to use corrosion- Weyerhaeuser distributors. Other treated connections in saddles can cause water resistant fasteners and connectors for Trus Joist® products may be custom ordered to collect and may prevent members all applications. Fasteners include nails, and may require lead times. from drying out readily. The ensuing high screws, and bolts. Connectors include joist moisture content can cause degradation in hangers, post bases, and hurricane or See the compatibility table above for more these areas. mudsill anchors. information about the preservative treatments used for protecting Trus Joist® products Architectural Design and Detailing: Proper Fasteners and connectors must have a against fungal decay and termite attack. architectural design and detailing are coating that will provide the required level of critical to help ensure that treated wood corrosion resistance for the treatment types, Wet Service and Dry Service Definitions members will perform satisfactorily when retention levels and end use conditions The definitions of wet and dry service vary. exposed to moisture. These may include the for Parallam® Plus PSL. To ensure that you The NDS® defines dry service for structural following: select the appropriate code-compliant hard- composite lumber products as an in-service • Protect members with roof overhangs ware, follow the hardware manuf acturer’s moisture content of less than 16%. CSA and proper flashing. recommendation for AWPA Use Category O86 defines dry service as a climatic • Elevate column bases to keep them out UC4A for columns and beam in exposed condition in which the average equilibrium of standing water and snow. above ground applications. For columns moisture content (EMC) of sawn lumber • Avoid connections that might trap water. exposed to salt water splash follow recom- over a year’s time is 15% or less and at no • Allow water to drain off members. mendations for UC4B. time exceeds 19%. • Provide adequate airflow to help dry out members and connections. Maintenance: The building’s owner can The EMC of wood is a function of the • Prevent continuous wood framing from reduce the effects caused by exposure relative humidity and temperature of the breaching the building envelope. through regular maintenance and routine surrounding environment. Not all exterior • When using solvent-based treatments inspection of exterior components.

Preservative Treatments Approved for Trus Joist® Engineered Wood Products 2 Technical Resource Sheet TJ-1020 | June 2018 Preservative Treatments Approved for Trus Joist® Engineered Wood Products

Reduction Factors These adjustment factors combine wet- meet the intended end-use requirements for Treated material should be used in all service and treatment-process reductions, pressure-treated or in-process-treated wet-service applications and in dry-service and should be used in place of the NDS® or Trus Joist® products. applications where wood-destroying CSA O86 wet-service adjustment factors. termites are present or wood comes into In addition, low-quality, damaged, or direct contact with concrete or masonry. Surface Applied Sealers or Coatings improperly applied coatings can trap When designing with treated products, Sealers or coatings are not effective moisture and retard the drying of exposed Weyerhaeuser allowable design stresses replacements for preservative pressure timbers, especially where the coating is must be adjusted for the selected treatment, even if they contain a breached by nails, bolts, joints, etc. Trapped treatment and service level as shown preservative. Current commercially available moisture provides an ideal environment for in the Adjustment Factors table below. coatings that contain a preservative do not decay fungi and termite activity.

Adjustment Factors for Allowable Design Stresses Preservative Treated Products Treatments Available Through Weyerhaeuser-Approved Treatments Available Through Weyerhaeuser Third-Party Treaters Copper Azole and CCA Zinc Borate TRIB® II TRU-CORE® I Design Property ® ® Microllam LVL, ® ® ® ® ® StrandGuard ® TimberStrand Microllam Parallam TJI Parallam Plus PSL ® Parallam PSL, TimberStrand LSL(1) LSL LVL PSL Joists and TJI® Joists SL 1 SL 2 SL 3 SL 1 SL 1 SL 1 SL 1 SL 1 SL 1 Joist 0.83 0.73 0.67 1.0 1.0 1.0 1.0 1.0 1.0 Shear modulus of elasticity, G Plank 0.77 0.68 0.62 1.0 1.0 1.0 1.0 1.0 1.0 Joist 0.83 0.73 0.67 1.0 1.0 1.0 1.0 1.0 1.0 Modulus of elasticity, E or Emin Plank 0.77 0.68 0.62 1.0 1.0 1.0 1.0 1.0 1.0 Joist 0.73 0.63 0.56 1.0 1.0 1.0 1.0 1.0 1.0 Flexural stress, F b Plank 0.71 0.60 0.54 1.0 1.0 1.0 1.0 1.0 1.0 Tension stress, Ft 0.75 0.69 0.66 1.0 1.0 1.0 1.0 1.0 1.0 Compression perpendicular Joist 0.64 0.45 0.34 1.0 1.0 0.89 1.0 1.0 1.0 to grain, Fc⊥ Plank 0.52 0.33 0.21 1.0 – (2) 0.75 0.95 0.85 NA Compression parallel 0.70 0.52 0.41 1.0 1.0 0.90 1.0 1.0 1.0 to grain, FcII Horizontal shear 0.83 0.68 0.59 1.0 1.0 0.90 0.95 1.0 1.0 parallel to grain, Fv (3) (3) (3) (3) (3) (3) Creep factor, CRP 0.20 0.60 0.85 – – – – – – (1) See the Trus Joist® Treated Sill Plates, Columns, and Studs Specifier's Guide (Reorder #TJ-8100) for allowable design stresses and more information. (2) Contact Weyerhaeuser for more information. (3) For more information on creep in dry service conditions, refer to the NDS® or CSA O86.

How to Use This Table General Notes 1. Select the appropriate preservative treatment. • Table is applicable for products used in beam orientation. For 2. Select the Trus Joist® product to be treated. plank orientation adjustment factors contact your Weyerhaeuser 3. Determine the appropriate Service Level from the first page. representative. 4. Multiply the allowable design stresses of the selected • The following formula approximates the total load deflection, ® Trus Joist product (as shown in current product literature), by including creep deflection (∆CD): the adjustment factors shown in the appropriate column. 5. Use the creep factor (CRP) shown in the appropriate column of Total load deflection: ∆TL = ∆LL + ∆DL + ∆CD the table and the formula under General Notes to approximate where: ∆CD ∆= [ DL + ∆LL (F)][CRP] the creep deflection under total load. F = 0.2 for floors; 0.3 for roofs

Nominal Connection Design Value Adjustment Factors for Parallam® Plus PSL Moisture Content Lateral Withdrawal Service Level at Connection Connections Connections SL1 or SL2 ≤ 28% 0.7 0.25 ≤ 28% 0.7 N.R.(1) SL3 > 28% 0.4 N.R.(1) (1) Withdrawal connections in Service Level 3 applications are not recommended (N.R.).

Preservative Treatments Approved for Trus Joist® Engineered Wood Products 3 Technical Resource Sheet TJ-1020 | June 2018 Preservative Treatments Approved for Trus Joist® Engineered Wood Products

Field-Applied Surface Treatments For Trus Joist® products treated with light- degradation from either the preservative Field-applied preservative treatment products organic solvent preservatives (LOSP), such as chemicals or their carriers. are intended for re-treating (coating) the TRIB II® (used in Hawaii), oil-based stains or surfaces of previously pressure-treated paints have been used successfully to Weyerhaeuser-Approved Treaters wood that has been cut, drilled or otherwise achieve a uniform appearance. Weyerhaeuser works with specific, approved machined in the field. The use of field-applied treating par tners to ensure a high-quality end preservative products as a substitute for Both untreated and treated wood products product. This process helps ensure that the properly pressure-treated Parallam® Plus PSL may exhibit discoloration, checking, warping, type of treatment used and how it is applied will not provide similar long term protection or splitting when exposed to the weather. are compatible with the wood product. and is not covered by the Weyerhaeuser and Appropriate maintenance, such as the Koppers Performance Chemicals, Inc. 30-year application of quality exterior stains and Warranties limited warranties. paints, will help reduce the extent of these The Weyerhaeuser Trus Joist® limited weathering effects. Commercial paints and product warranties are void if product Painting or Staining Treated Products finishes that are compatible with is treated at an unapproved facility. Customers may choose to paint or stain preservative-treated products do exist; Weyerhaeuser warranties are available at treated wood to even out the color variations however, finishes that seal in or trap moisture weyerhaeuser.com/woodproducts. of the treatment process. Products protected should not be used. with water-based treatments, such as Strandguard® TimberStrand® LSL, Preservative Treatments and Adhesives Parallam® Plus PSL, or TRU-CORE® I can be in Engineered Wood Products painted or stained with either oil- or water- The adhesives used in Trus Joist® engineered based finishes. However, these finishes may wood products have been qualified in not hide inherent surface irregularities, and accordance with ASTM 2559 for wet-use the final color may be affected by the tint of conditions by the adhesive manufacturer. the treatment. These adhesives are not su sceptible to

Additional Information About Preservative Treatments StrandGuard® TimberStrand® LSL: WARNING: This product can expose you to chemicals including wood dust which are known • Treated Sill Plates, Columns, and Studs Specifier's Guide (Reorder #TJ-8100) to the State of California to cause cancer, and available at weyerhaeuser.com/woodproducts/document-library/TJ-8100 methanol, which are known to the State of • SDS available at California to cause birth defects or other reproductive harm. Drilling, sawing, sanding or weyerhaeuser.com/application/files/7615/1311/1746/Zinc_Borate-treated_TimberStrand_LSL.pdf machining wood products can expose you to wood dust. Avoid inhaling wood dust or use a Parallam® Plus PSL: dust mask or other safeguards for personal • Parallam ® Plus PSL Specifier's Guide (Reorder #TJ-7102) protection. For more information go to www.P65Warnings.ca.gov and available at weyerhaeuser.com/woodproducts/document-library/TJ-7102 www.P65Warnings.ca.gov/wood. • Consumer Safety Sheet for Parallam® Plus PSL (Reorder #TJ-1021) available at weyerhaeuser.com/woodproducts/document-library/TJ-1021 • SDS for columns available at weyerhaeuser.com/application/files/6615/1311/1309/Parallam_Plus_PSL_CCA.pdf • SDS for beams and headers available at weyerhaeuser.com/application/files/6215/1311/1309/Parallam_Plus_PSL_CA-C.pdf

TRIB II® and TRU-CORE® I: Available from Honolulu Wood Treating, LLC, hwthawaii.com • SDS for TRIB II® and TRU-CORE® I are available through Honolulu Wood Treating or at hwthawaii.com

June 2018 • Reorder TJ-1020 CONTACT US 1.888.453.8358 • weyerhaeuser.com/woodproducts/contact

This document supersedes all previous versions. , Weyerhaeuser, Trus Joist, Microllam, Parallam, StrandGuard, TimberStrand, TJI, and Trus Joist are If this is more than one year old, contact your registered trademarks of Weyerhaeuser NR. © 2018 Weyerhaeuser NR Company. All rights reserved. dealer or Weyerhaeuser rep. TRIB II and TRU-CORE are registered trademarks of Kop-Coat, Inc.