Residential Building Inspector B1Building Planning and Life SafetyMedium
A residential building inspector is reviewing plans for a new single-family dwelling that includes a fireplace. The plans indicate the fireplace will have a masonry hearth. What is the minimum required thickness for this masonry hearth?
- A2 inches
- B8 inches
- C4 inches
- D6 inches
Show answer & explanationAnswer & explanation
Correct answer: C. 4 inches
To provide adequate protection from embers and heat, masonry fireplace hearths must meet a minimum thickness requirement. The IRC specifies a minimum thickness of 4 inches for such hearths.
Why the other options are wrong
- A. 2 inches is typically too thin for a masonry fireplace hearth to provide sufficient protection.
- B. 8 inches is significantly thicker than required for a standard masonry hearth.
- D. 6 inches exceeds the minimum requirement, but 4 inches is the specified minimum.
Fireplace Hearth Thickness
The minimum vertical dimension of a masonry fireplace hearth, designed to protect combustible floor coverings and structural elements from heat and embers.
- Protects from heat and sparks.
- Minimum thickness specified by code.
- Essential for fire safety around fireplaces.
Memory trick: Hearth's 'H' is 'Four' (4 inches) for safety's score.