Is My Attic 2x4s Or 2x6s

When you start a 2 4 project you can figure out all of your measurements in advance.

Is my attic 2x4s or 2x6s.

Should i do 12 ft 2x4s across as roof supports between the 4x4s or something bigger like 2x6s. 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. 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.

But if you only have 3 4 ft. The attic joists are only 2x4s and are 27 inch on center i double checked. Only reason for not choosing something bigger than 2x4 would be that they will be significantly cheaper if i can get away with them. But i want to do it right and if 2x6 would be way better i ll do them.

Steve demoor of wildlife solutions takes you through a first hand encounter with extensive attic damage due to squirrel problems in a home. 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. If joists are only 2x6 they may need reinforcement. If you have room to stand up then the strongbacks look like a good idea.

A lot depends on how much height you have available in this attic. 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. For example if you need 4 5 cuts of 2 4 you want to buy 2 10 2x4s instead of 4 8 2x4s. 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.

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. I talked to a structural engineer and he advised to sister the existing 2 4 joists. 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. 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.

If your joists are 2x6s or 2x8s they are not adequate for supporting attic flooring in a new living area and the furnishings and humans who will use them.