The three items from the new building code being addressed in this bulletin are:
- Continuity of Fire Separations
- Fasteners used with Treated Wood
- Engineer Stamped Truss Drawings for Part 9 Buildings and Single-Family Dwellings
Continuity of Fire Separations
Article 9.10.9.2. below now has new fire stopping requirements for the joints in drywall at required fire separations where the joints occur at the junction of ceiling and walls or walls and floors. Previously drywall joints in these locations were only required to be mudded and taped which lead to inconsistent and failed fire separations, to reduce these failures drywall joints occurring at these locations must now be continuously and fully supported by solid dimensional lumber or be fire-stopped with a ULC listed firestopping system. I.E. Hilti, 3M or other proprietary fire-stop system that has been tested per CAN/ULC-S115 and ASTM E2307.
9.10.9.2. Continuous Barrier
1) Except as permitted in Article 9.10.9.3., a wall or floor assembly required to be a fire separation shall be constructed as a continuous barrier against the spread of fire and retard the passage of smoke.
2) Except as permitted in Article 9.10.9.3., a wall or floor assembly required to be a smoke-tight barrier shall be constructed as a continuous barrier against the spread of smoke. (See Note A-9.10.9.2.(2) and (3).)
3) Except as provided in Sentence (6), the continuity of a fire separation where it abuts another fire separation or smoke-tight barrier, a floor, a ceiling, or a roof shall be maintained by a firestop that, when subjected to the fire test method in CAN/ULC-S115, “Standard Method of Fire Tests of Firestop Systems,” has an FT rating not less than the fire-resistance rating for the abutting fire separation. (See Note A-9.10.9.2.(2) and (3).) (See also Note A-3.1.8.3.(2).)
4) Except as provided in Sentence (6), joints located in a horizontal plane between a floor and an exterior wall shall be sealed by a firestop that, when subjected to the fire test method in ASTM E2307, “Standard Test Method for Determining Fire Resistance of Perimeter Fire Barriers Using Intermediate-Scale, Multi-storey Test Apparatus,” has an F rating not less than the fire-resistance rating for the horizontal fire separation.
5) Except as provided in Sentence (6), all gypsum board joints in the assemblies described in Sentences (1) and (2) shall conform to CSA A82.31-M, “Gypsum Board Application,” to maintain the integrity of the smoke-tight barrier over the entire surface.
6) Joints between ceilings and walls, between floors and walls, and between walls at corners need not comply with Sentences (3) to (5) where such joints consist of gypsum board that is attached to framing members and arranged so as to restrict the passage of flame and smoke through the joints. (See Note A-3.1.8.3.(5).)
Fasteners used with Treated Wood
Due to incompatible metal on metal chemical reactions between nails and screws (fasteners) and hangers (connecters) fasteners that resulted in corrosion in treated wood are now required to be hot dipped galvanized or galvannealed. It is advisable to check with the manufacturer for correct fastener selection.
9.23.2.4. Connections to Preservative-Treated Wood
1) Except as provided in Sentence (3), connectors in contact with preservative-treated wood shall be made of
a) hot-dipped, zinc-coated galvanized steel with a coating weight not less than Z550 conforming to ASTM A653/A653M, “Standard Specification for Steel Sheet, Zinc-Coated (Galvanized) or Zinc-Iron Alloy-Coated (Galvannealed) by the Hot-Dip Process,”
b) a material that provides an equivalent level of corrosion protection to that provided by the material described in Clause (a), or
c) stainless steel.
2) Fasteners used to attach the connectors referred to in Sentence (1) shall be made of
a) galvanized steel coated with zinc in accordance with ASTM A153/A153M, “Standard Specification for Zinc Coating (Hot-Dip) on Iron and Steel Hardware,” or
b) a material that provides an equivalent level of performance and is compatible with the connector.
3) Connectors and fasteners that are in contact with wood that has been treated with a disodium octaborate tetrahydrate (SBX (DOT)) or zinc borate preservative and is installed in a dry interior environment are permitted to be made of uncoated carbon steel. (See Note A-9.23.2.4.(3).)
9.23.14.11 Engineer Stamped Truss Drawings for Single Family Dwellings
In the past roof and floor truss design was typically completed at the truss plant on a computer by a technician however it was determined this type of work constituted engineering that required professional skills to design the trusses and connections in accordance with Part 4 of the code. Going forward, each individual truss drawing and the layout drawings will have to be stamped and signed by a registered professional engineer per article 9.23.14.11 and Part 4 of the National Building Code / 2023 Alberta Edition.
9.23.14.11. Roof Trusses
1) Wood roof trusses shall be designed in accordance with good engineering practice such as that described in TPIC 2019, “Truss Design Procedures and Specifications for Light Metal Plate Connected Wood Trusses.”
2) The joint connections used in trusses described in Sentence (1) shall be designed in conformance with the requirements in Subsection 4.3.1. (See Note A-9.23.14.11.(2).)
3) All member bracing shall be installed as per the truss design drawings, and continuous lateral bracing shall be adequately anchored to the roof and ceiling diaphragms at intervals no greater than 6.10 m o.c.
Note on 9.23.14.11. Wood Roof Truss Connections. Sentence 9.23.14.11.(2) requires that the connections used in wood roof trusses be designed in conformance with Subsection 4.3.1., and Sentence 2.4.1.2.(1) of Division C, which applies to all of Part 4, requires that the designer be a registered professional skilled in the work concerned. This has the effect of requiring that the trusses themselves be designed by registered professionals. Although this is a departure from the usual practice in Part 9, it is appropriate, since wood roof trusses are complex structures which depend on several components (chord members, web members, cross-bracing, connectors) working together to function safely. This complexity precludes the standardization of truss design into tables comprehensive enough to satisfy the variety of roof designs required by the housing industry.
We have very knowledgeable Safety Codes Officers that can assist in answering questions that may be relevant to the materials or projects. To speak with a Safety Codes Officer, call our office at 780-743-7813, or email inspections@rmwb.ca.
The Safety Codes Department is committed to supporting safe work across our region. If you have questions or concerns, please contact us at the phone or email address above. We are always happy to help!
