2 IRC Questions 1

[WARose]

2 International Residential Code questions (the 2015 version)......and I'm sorry if they seem silly but I am not someone who spends a lot of time in the IRC:

1. As far as I can tell, structural steel is completely excluded from this code correct? If you start putting steel on a house plan, you are then in the territory of needing to seal it right?

2. They have a header table for allowable (for flexural) loads [R602.7(1)], but does anyone know where/if they have that for top plates (single or doubled up)? It may be buried in code somewhere.

Thanks.

 

[EngineeringEric]

I think steel is considered an engineered element and therefore is required to be sealed. but you can just seal the beam's design in a letter and the plans not sealed. Some BCO accept just calcs without a seal (don't shoot the messenger!!). i'd say steel is excluded from the perspective limits of the IRC

The tables usually are for simple perspective cases. They do have tables for wall assembly, i want to say R6. that outlines top plate construction and splicing and so forth. they probably have limits on when it is applicable. They do allow single plates because they provide details on how to splice singles and what to do at the corner (if memory serves me). The between question is why are you looking to do a single top plate? that is a bad way to save 50$ per floor.

 

[WARose]

The between question is why are you looking to do a single top plate? that is a bad way to save 50$ per floor.

That's a good point......but, sometimes you get openings where you know it will work.....just wanted to locate in code where it actually says that.

 

[EngineeringEric]

How is this for explicit!

R602.3.2 Top plate.
Wood stud walls shall be capped with a double top plate installed to provide overlapping at corners and intersections with bearing partitions. End joints in top plates shall be offset at least 24 inches (610 mm). Joints in plates need not occur over studs. Plates shall be not less than 2-inches (51 mm) nominal thickness and have a width at least equal to the width of the studs.

Exception: A single top plate may be installed in stud walls, provided the plate is adequately tied at joints, corners and intersecting walls by a minimum 3-inch by 6-inch by a 0.036-inch-thick (76 mm by 152 mm by 0.914 mm) galvanized steel plate that is nailed to each wall or segment of wall by six 8d nails on each side, provided the rafters or joists are centered over the studs with a tolerance of no more than 1 inch (25 mm). The top plate may be omitted over lintels that are adequately tied to adjacent wall sections with steel plates or equivalent as previously described.

Thanks for quoting my typo there

 

[WARose]

Thanks EE.

 

[XR250]

I would not use a single top plate for the following reasons.... (the first 2 reflect single story structures)

1) A double plate provides more resistance to stop a tree from knifing thru the structure

2) A double top plate provides more horizontal spanning capabilities which helps with out-of-plane loads on a gable end

3) A double plate is a better intentional or unintentional shearwall collector.

4) A double plate is more forgiving to framing alignment problems or if a post is missed.