Massachusetts Construction Supervisor License (CSL) Practice Test

Which statement about masonry chimneys in a one or two family dwelling is NOT true?

1. Chimneys may support additional loads

2. Must extend at least 3 feet above the highest point

3. Chimneys may be unlined

4. Walls must be at least 4 inches thick

The correct answer is: Chimneys may be unlined

The assertion that chimneys may be unlined is not true regarding masonry chimneys in one or two-family dwellings. In Massachusetts, building codes require that masonry chimneys be constructed with lining to ensure safe and efficient venting of combustion gases. An unlined chimney can pose significant risks, including smoke and gases permeating into the structure, as well as increased flammability and chimney fires. Proper lining also helps protect the masonry from the corrosive effects of flue gases and thermal expansion, thereby extending the life of the chimney. The other statements hold true in the context of masonry chimneys. For example, chimneys may support additional loads, which indicates that they can be designed to bear structural weight when accounted for in the overall design. Additionally, a chimney must extend at least three feet above any point where it passes through the roof to reduce the chances of downdrafts and ensure proper ventilation. The requirement for walls to be at least four inches thick assures that they have adequate structural integrity and thermal resistance to operate safely.