What are the code requirements for an attic catwalk/walkway?
Tuesday, November 24, 2020
A walkway is not required in an attic unless there is an appliance installed in it, such as a water heater or air handler. You can read about all the code requirements for safe walkway access to an appliance in the attic at our blog post What are the building code requirements for installing an appliance (furnace, air handler, water heater) in the attic?
If you just want a way to safely move around in the attic, or have a platform for storage, here’s our recommendations:
•• Use a minimum of 1/2” plywood, but preferably 5/8”, for the catwalk and any storage area.
•• Secure the plywood at two opposite ends to the bottom chords of trusses or ceiling rafters, with screws or nails, and across at least two spans with no wood overhanging the bearing.
•• Do not install any plywood over electrical cables. This would end up compressing the cable between the plywood and wood below it, which can cause an electrical short over time.
•• And, finally, don’t cut away any truss chords or webs to make more room. This may significantly weaken a truss, because each one is designed to transfer the roof load to others and end up at the bearing point at the end of the truss. Removing a chord or web is like taking a link out of a chain. See our blog post How much of a roof truss can I cut out to make a storage platform in the attic?
But the biggest hazard we have come across, after exploring thousands of attics during home inspections, is loose sheets of plywood laid around as a walking surface, especially ones with an edge cantilevered past a bearing point. Step on it at the wrong place and the plywood slides and flips up, and you go down, possibly through the ceiling. Also, a catwalk with a gap to step over, like in the photo at the top of the page, is not acceptable. Go to our article What are the hazards to avoid when going into an attic? for more on how to safely maneuver around in an attic.
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