A 2x6 for an uninhabited attic with no storage and a dead load of 5psf ceiling drywall if you have it and incidental hanging stuff etc is prescribed per code.
Reinforce 2x6 attic joists to handle live loads.
In this example the table for a 40 psf live load 10 psf dead load floor shows that the joist in the example have a required fb value of 1 644 and an e value of at least 2 400 000.
This is a great answer.
Discussion on the integrity of 2x6 ceiling joists holding up heavy loads.
The wooden joists or beams over your garage help hold your roof in place.
Attic office attic playroom attic closet attic library attic doors attic window barn doors attic renovation attic remodel.
Positioning the new joist adjacent to the existing preserves precious ceiling but it does come with some potential complications.
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.
Often existing joist bays are filled with electrical and heating ducts that will need to be relocated.
Discussion on the integrity of 2x6 ceiling joists holding up heavy loads.
Use span tables for progressively heavier loads until you find the limits of your floor.
There are code reguired design loads for various types of spaces usually an allocation for dead load the building and fixed things and live load people and furniture things that can move around design loads will be significantly less than the load that will cause unacceptable bending or failure which is nearly impossible to know given all the variables and unknowns involved.
Strengthening attic joists for live loads by sistering.
How to reinforce 2 6 ceiling joists to handle heavy loads.
Sistering is the process of adding a new joist next to each existing joist.
I went to get a permit from the city to finish the attic and they said i needed to reinforce the floor since for a live load it was not strong enough for our span below about 12.
Also says leom the load rating for an i joist is 100 psf live load 20 psf for a dead load.
Sistering installing new larger joists next to the existing ones is one way to bring your attic floor up to code.
In the case of 2x6 joists you can pair them up with additional 2x6 joists by nailing them together.
In my 80 year old house the attic had 2x6 floor joists about 16 oc.
If the attic joists are not adequate one way to strengthen the floor for live loads is to sister the old joists.
A 2x8 2 grade or better in common framing species will meet code for limited storage and is defined as 10psf dead load and 20psf live load.
Where they connect to both the top and bottom joists each gusset pair will transfer approximately 100 pounds that s 50 psf of floor load times the 3 foot gusset spacing times the 16 inch joist spacing divided by the two joists.
In this case your joists are adequate to support a 30 psf live load and 10 psf dead load.
How to reinforce 2x6 ceiling joists to handle heavy loads fine homebuilding.
