Is it okay to put plywood flooring in an attic?

Friday, February 28, 2020

Installing plywood flooring in the attic is an easy homeowner upgrade that allows for more attic storage without the possibility of heavier items damaging the ceiling below. We recommend using 1/2” CDX plywood. There are, however, three potential problems to avoid when placing the plywood panels:

1) Don’t remove any truss chords, like in the example of how not to do it shown above, to open up the area for more storage. it weakens the roof structure, will be called out by a home inspector when you sell the house, and is expensive to repair correctly.

2) The plywood should be nailed or screwed in place, with no ends cantilevered past the bearing. Loose plywood pieces laid over the ceiling rafters or bottom chord of the trusses can slide off their bearing as you crawl over them, tip, and send you and your storage boxes through the ceiling. Also, it’s best for the plywood to span over three or more trusses for stability.

3) Don’t sandwich any electrical cables between the plywood and the ceiling rafters or truss bottom chord. This can damage the cable sheathing and cause a short.

    Also, see our blog post What are the hazards to avoid when going into an attic?

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Here’s links to a collection of our blog posts about ATTICS:

What is the most common type of roof-to-wall attachment? What are the building code requirements for installing an appliance (furnace, air handler, water heater) in the attic?

How do I safely remove a dead rodent (rat, mouse or squirrel) from the attic?

What are the common problems with attic insulation? 

Why is there no attic access hatch in the house?

How do I safely clean up rodent (rat, mouse or squirrel) urine or droppings the attic?

Why is there no attic access hatch in the house?

 Is an attic required to have a light by the building code? 

What is the building code requirement for an attic access hatch, scuttle, or door?

Why is vermiculite attic insulation a problem for both buyers and sellers of a home? 

What are the code requirements for NM-cable (nonmetallic-sheathed cable or Romex®) in an attic? 

What are the warning signs of a dangerous attic pull-down ladder?

Do home inspectors go on the roof? Do they get in the attic?

How much of a roof truss can I cut out to make a storage platform in the attic? 

• When was a fire separation in the attic first required between sides of a duplex? 

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