Massachusetts Construction Supervisor License (CSL) Practice Test

Is a vapor retarder necessary in a heated accessory garage of a single family dwelling?

1. Yes

2. No

3. Only in colder climates

4. Only if the garage is underground

The correct answer is: Yes

A vapor retarder is indeed necessary in a heated accessory garage of a single-family dwelling. The purpose of a vapor retarder is to minimize moisture movement from the living spaces into the garage, where it can condense and create issues like mold growth, structural wood decay, and damage to stored items. In a heated garage, the difference in temperature between the interior air and the cooler surfaces can lead to moisture condensation, making the presence of a vapor retarder a critical component to help control moisture migration. In contrast to the other options, which either limit the requirement to specific conditions or entirely dismiss it, recognizing the need for a vapor retarder in a heated environment supports building practices aimed at ensuring long-term durability and a healthy indoor environment. It is a proactive measure that aligns with good construction practice, particularly in climates that experience variations in temperature and humidity.