EWP - Frequently Asked Questions

Can I mix different EWP manufacturers of a product technology on a project?
This is not recommended as product design values can vary between manufacturers. In addition, manufacturers’ warranties might be affected by mixing products on a project. However, there may be certain situations and conditions where it could be acceptable. Check with your lumber dealer or supplier, and the product manufacturer prior to installing products.
Do all manufacturers of SCL, ie. Laminated Veneer Lumber, Glu-Laminated Timber, Laminated Strand Lumber, etc. allow drilling of holes through their products. Where and what size can I drill?
Generally, holes can be drilled through SCL products. But limitations and restrictions are usually enforced. Product Design Values between various manufacturers and various product technologies can differ. Some technologies of SCL are very restrictive on size and location of holes. Check the manufacturers specifications and design guides for reference. It’s always good practice to confirm with the manufacturer or the manufacturer’s distributor/dealer prior to cutting or drilling holes.
Are all engineered wood manufacturers required to have CCMC reports and approvals for their products?
As per, NBCC,, Evaluation reports issued by the Canadian Construction Materials Centre, National Research Council of Canada, or an organization approved by the Provincial Building Administrator may be used in determining compliance with the requirements of this Code.
Most provinces, territories and municipalities use CCMC's evaluation reports as a basis for determining compliance of new products to codes.
Are there any differences between approved fire assemblies such as APA, PFS, Intertek, or NBCC?
No…Fire tests should be tested in accordance with the CAN/ULC S101 Standard. In addition, the testing agency is required to be qualified / approved under the Standards Council of Canada.
My supplier never shipped OSB Rimboard for my floor system. Can I substitute ripped plywood panels, ripped OSB panels, or conventional lumber in its place?
No…Rimboard must be an approved product manufactured for this specific purpose. OSB/ LSL Rimboard is typically manufactured in 1 1/8” thickness, with depths that match I-Joist depths. OSB/LSL Rimboard has compressive values that are published by each manufacturer. It is the designers responsibility to ensure the Rimboard specified is capable of transferring the design load to the wall or foundation it is bearing on. Check with manufacturer for more detail.
Do manufacturers carry warranties for their proprietary engineered wood products and systems?
Yes…every EWP manufacturer warrants their products with a manufacturers’ warranty. Most warranties protect the homeowner against any manufacturing / workmanship defects. Most warranties do not cover improper installation, poor workmanship or inadequate handling and storage. Check with the manufacturer for more detail.
What is dry service condition?
• Wood is a hygroscopic material; the ability to gain and lose moisture from the surrounding environment. Moisture exchange between wood and air depends on the relative humidity and temperature of the air and the current amount of water in the wood. Specified strengths of wood structural elements are based on test results for dry service.
• The following definition of dry service can be found in all engineered wood manufacturers CCMC evaluation reports in Section 3: Conditions and Limitations.
All lumber, wood-based panels and proprietary engineered wood products are intended for “dry service conditions.” “Dry service” is defined as the in-service environment under which the equilibrium moisture content (MC) of lumber is 15% or less over a year and does not exceed 19% at any time. Wood contained within the interior of dry, heated or unheated buildings has generally been found to have a MC between 6% and 14% according to season and location. During construction, all wood-based products should be protected from the weather to ensure that the 19% MC is not exceeded in accordance with the NBC 2010, Division B, Article
Can a dimensional lumber structural member be substituted with SCL?
• Yes, the product category of SCL (structural composite lumber) can be substituted for dimensional lumber. The strength characteristics of SCL products provide “equivalent or superior strength compared to dimensional lumber” (CMHC-Canadian Wood-Frame House Construction). A design analysis is always appropriate.
• The following statement can be found in all SCL manufacturers CCMC evaluation reports in Section 3: Conditions and Limitations.
The product is intended for use in construction as an alternative material to lumber. Proprietary design values presented for the product are to be used by professional engineers for design in accordance with CSA O86 for structural applications such as beams, headers, joists, rafters, and columns as intended by the product manufacturer.
• For more information, see the CCMC website.
Are there any differences between proprietary and generic EWP Design Software?
Whether the software is provided by the manufacturer or an independent third-party firm, they all are written in accordance with accepted engineering design procedures stipulated in CSA O86, NBCC, and OBC. EWP design software, single member component design or whole house design, is a critical tool used in every EWP design office. EWP design software is used to design for strength and serviceability where input loads, bracing, and deflection limits presented on the layout placement plan and/or component design report are entered by the user. As is the case with any construction document, the output from software programs shall be reviewed by the project’s design professional of record to assure its adequacy for the intended application.