An inaccessible attic space on the other hand might have a live load of only 20 psf.
2x12 floor joists for attic room above garage.
Joist dimensions are only part of the equation.
A room used solely for sleeping might need to carry only 30 psf whereas a garage floor over a basement would need 50 psf or higher.
If you have an attic over your garage these joists also bear the load of your attic flooring and any materials you store in the attic.
Attic joists for live loads.
But you can still double the capacity of the existing 2x6s in the attic floor so first let s make sure that s enough for your situation.
The rest of the space is situated over the laundry room to tap into existing pipe chases.
The wooden joists or beams over your garage help hold your roof in place.
Don t forget the impact on adjacent spaces.
First floor live loads have higher requirements than second floor live loads 40 pounds per square foot vs.
Standard joist spacing for the installation of attic flooring materials is 16 inches on center oc meaning the distance from the center of one joist to the center of the next joist is 16 inches.
If you need a storage area above your garage strong ceiling joists are necessary to support the added weight.
You also need to ensure that the joist spacing is adequate.