In regions where the average January temperature is 25°F or less, what is required for wood shingles?

In regions where the average January temperature is 25°F or less, solid sheathing is required for wood shingles primarily due to the need for improved insulation and moisture control. In colder climates, solid sheathing gives a more continuous and uniform support for shingles, which helps to prevent drafts and air leakage that can occur with spaced boards or other less solid structures.

Additionally, solid sheathing can help manage ice dam formation, which is a common issue in colder temperatures. Ice dams can cause significant water damage; therefore, a solid surface under the shingles aids in preventing water from infiltrating through gaps. This requirement ensures that the shingles are properly installed in a manner that allows them to perform effectively and last longer despite the adverse weather conditions characteristic of colder regions.

Wood framing, metal sheathing, and composite materials may not provide the same level of insulation or moisture management needed in these specific low-temperature environments, which is why they are not the appropriate choices.