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Project MgmtConstructionhard63% of exam part

A contractor needs to install a tile roof on a building with a roof slope of 3:12. What is the minimum underlayment requirement for this application in Florida?

Correct Answer

C) Double layer of #15 felt

For tile roofs with slopes between 2.5:12 and 4:12, the Florida Building Code requires double layer underlayment to provide adequate weather protection due to the lower slope.

Answer Options
A
Single layer of #15 felt
B
Single layer of #30 felt
C
Double layer of #15 felt
D
Self-adhering membrane

Why This Is the Correct Answer

CORRECT_ANSWER - For tile roofs with slopes between 2.5:12 and 4:12, the Florida Building Code requires double layer underlayment because the lower slope creates greater risk of water infiltration. A 3:12 slope falls within this range where single layer protection is insufficient. The double layer provides redundant protection against wind-driven rain that can penetrate under tiles on lower-sloped roofs.

Why the Other Options Are Wrong

Option A: Single layer of #15 felt

Single layer of #15 felt is insufficient for tile roofs at 3:12 slope. This minimal underlayment doesn't provide adequate protection against water infiltration that can occur with lower slope tile installations.

Option B: Single layer of #30 felt

While #30 felt is heavier than #15 felt, a single layer still doesn't meet the Florida Building Code requirement for tile roofs at 3:12 slope. The code specifically requires double layer protection in this slope range.

Option D: Self-adhering membrane

Self-adhering membrane is typically used for ice dam protection in cold climates or special waterproofing applications, but it's not the standard requirement for tile roofs at 3:12 slope in Florida. The code specifies double layer felt underlayment for this application.

Memory Technique

Remember '3 in the middle needs double' - a 3:12 slope is in the middle range (2.5-4) that requires double layer protection

Reference Hint

Florida Building Code Chapter 15 - Roof Assemblies and Rooftop Structures, specifically the section on underlayment requirements for tile roofing systems

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