International Compliance Association (ICA) Home Inspector Practice Exam

Which type of shingles has the longest expected service life?

1. Wood

2. Asphalt

3. Slate

4. Fiberglass

The correct answer is: Slate

Slate shingles are known for their impressive longevity, often lasting over a century when properly maintained. One key factor contributing to their extended service life is their natural composition; slate is a dense, metamorphic rock that resists weathering, meaning it can withstand harsh environmental conditions better than the alternatives. Additionally, because slate is not susceptible to rot, mold, or insect damage, it further extends the lifespan of the roof. In contrast, wood shingles and asphalt shingles typically have a shorter lifespan due to their organic materials. Wood can be prone to decay, and while it can last for decades with proper treatment, it generally does not match the longevity of slate. Asphalt shingles usually last around 20-30 years, largely due to wear and tear from weather exposure, ultraviolet light degradation, and potential damage from moss or algae. Fiberglass shingles, a type of asphalt shingle, do offer some improvements in durability but still do not approach the longevity that slate provides. Overall, when considering longevity and service life, slate shingles stand out as the most durable choice, due to their inherent properties and resistance to various forms of deterioration.