Magilla
REGISTERED
I’m working on a multi residential project of 62 units built in 1998 - 2003. Wondering what year hurricane ties became mandatory for attaching to top plate and the trusses. The trusses on this project are at 2 feet on centre.
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Hurricane Ties for residential trusses
- Thread starter Magilla
- Start date
They are not, nor have they ever been, mandatory via the provisions of the IRC. What the IRC does require is uplift resistance, particularly where the uplift reaction exceeds 200-lbs.
This section was updated in the 2018 to 2021 code, but the sections herein are pretty similar in intent. Depending on your location, I can try to figure out what the legacy code was at the time of construction. Looks like you may be out of Canada, and things are a bit different north of the 49th.
Where the uplift force does not exceed 200 pounds (90.8 kg), rafters and trusses spaced not more than 24 inches (610 mm) on center shall be permitted to be attached to their supporting wall assemblies in accordance with Table R602.3(1).
Where the basic wind speed does not exceed 115 mph, the wind exposure category is B, the roof pitch is 5:12 (42-percent slope) or greater, and the roof span is 32 feet (9754 mm) or less, rafters and trusses spaced not more than 24 inches (610 mm) on center shall be permitted to be attached to their supporting wall assemblies in accordance with Table R602.3(1).
VS.
Roof assemblies shall have uplift resistance in accordance with Sections R802.11.1 and R802.11.2.
Exceptions: Rafters or trusses shall be permitted to be attached to their supporting wall assemblies in accordance with Table R602.3(1) where either of the following occur:
This section was updated in the 2018 to 2021 code, but the sections herein are pretty similar in intent. Depending on your location, I can try to figure out what the legacy code was at the time of construction. Looks like you may be out of Canada, and things are a bit different north of the 49th.
2018 IRC R802.11.1 Uplift Resistance
Roof assemblies shall have uplift resistance in accordance with Sections R802.11.1.1 and R802.11.1.2.Where the uplift force does not exceed 200 pounds (90.8 kg), rafters and trusses spaced not more than 24 inches (610 mm) on center shall be permitted to be attached to their supporting wall assemblies in accordance with Table R602.3(1).
Where the basic wind speed does not exceed 115 mph, the wind exposure category is B, the roof pitch is 5:12 (42-percent slope) or greater, and the roof span is 32 feet (9754 mm) or less, rafters and trusses spaced not more than 24 inches (610 mm) on center shall be permitted to be attached to their supporting wall assemblies in accordance with Table R602.3(1).
VS.
2021 IRC R802.11 Roof Tie Uplift Resistance
Roof assemblies shall have uplift resistance in accordance with Sections R802.11.1 and R802.11.2.Exceptions: Rafters or trusses shall be permitted to be attached to their supporting wall assemblies in accordance with Table R602.3(1) where either of the following occur:
- Where the uplift force per rafter or truss does not exceed 200 pounds (90.8 kg) as determined by Table R802.11.
- Where the basic wind speed does not exceed 115 miles per hour (51.4 m/s), the wind exposure category is B, the roof pitch is 5 units vertical in 12 units horizontal (42-percent slope) or greater, the roof span is 32 feet (9754 mm) or less, and rafters and trusses are spaced not more than 24 inches (610 mm) on center.
(table ommitted)
I don’t know if it matters but this is coming from Canada. In Canada Hurricane is a professional wrestler.
Last edited:
Sifu
SAWHORSE
- Joined
- Sep 3, 2011
- Messages
- 3,315
As a 62 unit MF, this might not have been administered out of a residential code. Since the IBC/IRC may not have been used, it is possible it was UBC, or based on the location in the profile, whatever commercial code would have been in use in Canada?? If codes there/then are similar to ours today it could have likely been specified by the designing engineer. But that is all speculation, as we don't know where or what codes were enforced or used, or if an engineer designed it. Either way, as stated, in ICC land they are not mandatory.
Hi Magilla, welcome.
Assuming this is a Pt3 building, there would have been a structural engineer involved. The hurricane fasteners would have been part of the engineered design, which is not prescriptive, but performance based. So the requirement is for the engineer to design the roof so that it will not fall off under load, and this could be done a variety of ways.
Hope this helps?
Assuming this is a Pt3 building, there would have been a structural engineer involved. The hurricane fasteners would have been part of the engineered design, which is not prescriptive, but performance based. So the requirement is for the engineer to design the roof so that it will not fall off under load, and this could be done a variety of ways.
Hope this helps?