Understanding Appleton, Wisconsin’s Roofing Codes: A Guide for Home and Business Owners
In the city of Appleton, strict roofing codes have been established to ensure the safety and integrity of buildings. These codes, detailed in SPS 321.27, cover various aspects of roof design and framing.
In this article about Appleton roofing codes, we aim break down these complex regulations in a comprehensible way in an effort to help both homeowners and professional roofers understand the essential requirements.
Structural Design & Load Requirements
Under SPS 321.27(1), the structural design of roofs must support not only the dead load (weight of the roof structure itself) but also the minimum live loads (external forces like snow) as stipulated under SPS 321.02.
Importantly, the joist and rafter tables in chapter SPS 325 Appendix A are applicable only for roofs with a minimum slope of 3 in 12. Roofs with lesser slopes require a more meticulous engineering analysis or the addition of a ridge beam.
A crucial consideration is the snow load on sloped roofs. For slopes greater than 30 degrees, the snow load can be reduced by multiplying it by a coefficient, Cs, which is calculated based on the roof’s slope angle.
This reduction accounts for the decreased likelihood of snow accumulation on steeper roofs.
Lateral Restraint & Uplift Forces
Section 321.27(2) addresses the need for lateral restraint of walls to absorb the horizontal thrust produced by sloping roofs. This can be achieved through wall ties, ceiling joists, beams at the ridge or wall, or a system designed through structural analysis.
The code also mandates roofs to withstand uplift and suction forces, as detailed in subsection (3). Roofs must endure a minimum upward pressure of 20 pounds per square foot, including roof overhangs and other projections.
Additionally, specific anchorage requirements are set for roof framing members, ensuring they are securely fastened to the load-bearing walls.
Roof Rafters & Joists Specifications
The section 321.27(4) on roof rafters includes guidelines for notching, fastening to the wall, collar ties, and ridge boards. For instance, rafters must be notched to fit the exterior wall plate and fastened securely.
Collar ties are required on every third pair of abutting roof rafters or every 48 inches, whichever is less, to stabilize the roof at the ridge. The specifications for ridge boards vary depending on the positioning of the rafters.
Ceiling joists, as per section (5), must be nailed to exterior walls and rafters, with specific requirements for lapping and fastening at the ends.
They also need to be connected to parallel ceiling joists or rafters using engineered clips, straps, or hangers, or designed through structural analysis.
Valley Rafters, Hip Rafters, & Roof Trusses
Valley and hip rafters, covered in section (6), have particular requirements for bearing and support.
For instance, valley rafters must be doubled in thickness and deeper than common rafters when no bearing is provided at the intersection of two roof areas.
Hip rafters should also be deeper to permit full contact with the jack rafter.
For roof trusses, outlined in section (7), the design must comply with TPI 1 and the NDS adopted under s. SPS 320.24. Truss members should not be altered without proper authorization.
Notching and Boring Regulations
Section (8) details the permissible extent of notching and boring in beams, girders, ceiling joists, and rafters.
These rules are crucial to maintain the structural integrity of these components.
For example, notches in the top or bottom of joists and rafters are limited in depth and length and cannot be located in the middle third of the span.
Roof Sheathing, Boards, & Planking Standards
Finally, section (9) focuses on the specifics of roof sheathing, boards, and planking.
It specifies the allowable loads and spans for structural sheathing, the minimum thickness for roof boards depending on rafter spacing, and the requirements for roof planks, including their installation/replacement and fastening.
Read More: When’s the Best Time to Install a Roof?
Appleton Roofing Codes: In Conclusion
Home and business owners alike should be aware of these regulations, while certified professional roofing contractors are obligated to follow them meticulously. By doing so, they ensure that roofing structures are not only compliant but also capable of withstanding various environmental pressures.
ACS Roofing has more than twenty years installing asphalt, metal/steel, and rubber roofing in the cities of Appleton, Menasha, Neenah, Kimberly, Kaukauna, Oshkosh, and the Fox Valley area. Our roofing services include residential and commercial roofing, garages, windows, doors, gutters, siding, and more.
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