Mixed-species Cross-laminated Timber Layup Tests Using WWPA White-fir Species Group

Sep 2, 2026

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This report details mixed-species cross-laminated timber (CLT) layup tests conducted using the WWPA white-fir species group. The research involved utilizing both Melamine Formaldehyde (MF) and Polyurethane (PUR) adhesives across different panel configurations, specifically 3-ply and 5-ply lamellae. The study meticulously recorded the average moisture content (MC) of both white-fir and Douglas-fir species, along with environmental conditions such as temperature (Fahrenheit) and relative humidity (RH%) during the layup process. Panel 1, using MF adhesive, consisted of 3-ply lamellae and exhibited an average white-fir MC of 9.7% and Douglas-fir MC of 15.1% under 63°F and 32% RH. Panel 2, also with MF, used 5-ply lamellae and showed a white-fir MC of 11.0% and Douglas-fir MC of 16.5% under identical environmental conditions. The majority of the tests, however, focused on PUR adhesive. For 3-ply constructions with PUR, moisture content and environmental data varied across multiple panels, with white-fir MC ranging from 8.4% to 10.2% and Douglas-fir MC from 10.0% to 14.9%, while temperature remained around 63°F and RH fluctuated between 26% and 36%. For 5-ply constructions with PUR, white-fir MC levels were generally lower, between 8.3% and 10.1%, and Douglas-fir MC ranged from 10.7% to 14.3%, with temperatures around 61-63°F and RH between 23% and 32%. The data suggests variations in adhesive performance and wood species moisture behavior under controlled environmental settings, providing crucial insights for optimizing CLT manufacturing processes with diverse wood species.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages44

Reading Time1 h 51 min

AccessFree to download

Mixed-species Cross-laminated Timber Layup Tests

Panel Data and Environmental Conditions

Adhesives and Lamellae Configuration

Moisture Content and RH%

FAQs

What types of adhesives were used in the CLT layup tests?

The tests utilized Melamine Formaldehyde (MF) and Polyurethane (PUR) adhesives.

What were the two main types of wood species groupings tested?

The tests employed the WWPA white-fir species group, including white-fir and Douglas-fir.

What environmental factors were recorded during the layup process?

Average moisture content of the wood, temperature in Fahrenheit, and relative humidity in percentage were recorded.

What were the different ply configurations used for the lamellae?

The lamellae were tested in both 3-ply and 5-ply configurations.

Sep 2, 2026

Upload by Skyler