CSLB Class B General Contractor's License Practice Exam

What is the purpose of cross ventilation in attics, according to building codes?

1. To allow light into the attic

2. To reduce moisture build-up

3. To improve airflow

4. To provide insulation

The correct answer is: To reduce moisture build-up

The purpose of cross ventilation in attics is primarily to reduce moisture build-up. Proper ventilation is crucial in any building, especially in attics, as it helps to manage temperature and moisture levels. Excess moisture can lead to a variety of problems, including mold growth, wood rot, and deterioration of roofing materials. By allowing air to circulate through the attic space, cross ventilation helps to evaporate any moisture that accumulates, thereby protecting the structural integrity of the building and ensuring a healthier living environment. While light, improved airflow, and insulation are all important aspects of building design, they do not address the specific issue of moisture control that cross ventilation tackles. Light may enhance the usability of an attic space, improved airflow can support overall ventilation, and insulation is crucial for energy efficiency, but none of these functions directly relate to the mitigation of moisture issues that cross ventilation is specifically designed to manage. The focus on moisture reduction underlines why this aspect of ventilation is emphasized in building codes.