In the case of 2x6 joists you can pair them up with additional 2x6 joists by nailing them together.
Loads for attic.
If your existing attic flooring isn t adequate for conversion to a living space all is not lost.
Girder load width half joist span live load on roof local requirements for wind and snow.
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.
When used for storage only dead load of attic floor not floored 10 lbs.
Live load on attic floor local requirements.
Virtually any attic floor can be brought up to code it s just a matter of how much.
Strengthening attic joists for live loads by sistering.
Sistering is the process of adding a new joist next to each existing joist.
If the attic joists are not adequate one way to strengthen the floor for live loads is to sister the old joists.
Ft dead load of roof of wood shingle construction 10 lbs.
An inaccessible attic space on the other hand might have a live load of only 20 psf.
However if the attic is intended for storage the attic live load or some portion should also be considered for the design of.