A carpenter is preparing to install a large, heavy appliance (e.g., a commercial-grade refrigerator) directly above a section of floor system. The current joist span allows for standard floor loads. To adequately support the concentrated load, what is the most effective modification to the floor framing?

Question: A carpenter is preparing to install a large, heavy appliance (e.g., a commercial-grade refrigerator) directly above a section of floor system. The current joist span allows for standard floor loads. To adequately support the concentrated load, what is the most effective modification to the floor framing?

Answer options:

• Increase the subfloor thickness in that area to 25 mm.
• Add cross-bridging between the joists in the affected bay. ✅ Install additional joists (doublers) directly under the anticipated load area.
• Reduce the joist spacing for a small section around the appliance.

Correct answer: Install additional joists (doublers) directly under the anticipated load area.

Explanation: For concentrated loads like heavy appliances, the most effective method to increase the load-bearing capacity of the floor is to add additional joists (doublers) directly beneath the load. This effectively reduces the span for that specific area and distributes the weight over more framing members, significantly strengthening the system.