Is My Attic 2x4s Or 2x6s

If you do this you can plan what size 2x4s you want to purchase then see if there s a good combination so you are left with the least amount of scrap.

Is my attic 2x4s or 2x6s.

For example if you need 4 5 cuts of 2 4 you want to buy 2 10 2x4s instead of 4 8 2x4s. A lot depends on how much height you have available in this attic. The attic joists are only 2x4s and are 27 inch on center i double checked. But if you only have 3 4 ft.

If you have room to stand up then the strongbacks look like a good idea. Should i do 12 ft 2x4s across as roof supports between the 4x4s or something bigger like 2x6s. My ultimate plan is to sister the joists to make a sturdier attic ceiling blow in insulation on the roof and put plywood across the joists for a storage platform for my boxes christmas decorations etc. But i want to do it right and if 2x6 would be way better i ll do them.

If the joists are larger they might. 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. To the ridge simple sistering with 2x6 s should be strong enough for the amount of weight you d ever be likely to put up there. Many older homes have actual 2x4s not the 1 1 2 x 3 1 2 that we call 2x4s today.

The building inspector should be able to check things outs. Jumping up and down may reveal little or no bounce in attic floor but it s not the same as when furniture and books are added. Because 2x6s are 2 inches deeper than 2x4s a house built with 2x4 vs 2x6 walls will be a total of 4 inches wider and deeper inside than the same house built with 2x6s. If joists are only 2x6 they may need reinforcement.

My calculations tell me assuming 2 southern yellow pine joists which are common in my area that 2x6s 16 inches on center will span 9 feet 9 inches with allowable deflection being the governing factor. That means that for a 2 400 square foot house the interior of a 2x6 built house will be about 33 5 square feet smaller overall than that of a 2x4 built house. If the answer is to get a structural engineer then that s out of their budget so we ll just probably be forced to put in the 2x6s though i bet the 2x4s or sistered 2x4s would actually be enough for such a low attic space. I talked to a structural engineer and he advised to sister the existing 2 4 joists.

Only reason for not choosing something bigger than 2x4 would be that they will be significantly cheaper if i can get away with them.