Joist dimensions are only part of the equation.
Attic flooring thickness.
Note from this chart that the ideal r value differs for each part of your home.
Purchase half inch 1 27 cm thick plywood to act as your flooring.
Cdx plywood should be a minimum of 7 16 inch thick.
If you plan on placing the plywood around the perimeter of the opening or door and using it only to store light boxes or materials 1 2 inch thick plywood should suffice.
Use old boards that are close to the same thickness in a given section of the attic however.
As an example a floor space that totals 70 sq.
Attic joists for live loads.
7 16 15 32 and 1 2 inch thick panels require joists spaced 16 inches on center.
To prevent homeowners from building strangely configured and potentially dangerous spaces.
You ll need to make sure that the plywood can fit through your attic door.
The thinner plywood is acceptable when the joist spacing is 16 inches.
It s a good idea to rip long thinner strips of plywood that will fit through the attic door.
For example if you have a type of insulation that has an r value of r 5 per inch of thickness you will need a depth of 6 inches of this insulation installed your attic to reach r 30 if you live in zones 2 or 3.
These lightweight easy to manage panels can be installed by even the most inexperienced homeowner in about 15 minutes.
Attic flooring panels are easy to install with their interlocking edges.
More product details close.
19 32 and 5 8 inch thick.
Take the measurements for your subfloor and measure enough plywood so that you can cover the entire frame.
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 ever need to cover them with finished flooring you can always nail down another subflooring before installing tile or hardwood.
Floor space dimensions.
The thicknesses are as follows.
No matter what the spacing is on your ceiling joists 3 4 inch plywood should be used if you plan on walking on it.
Would still not be allowed because its 4 x 17 5 dimensions.
A single 4 pack covers approximately 10 sq.
Attic joists that are made from 2x8s may be acceptable for building your attic floor but because every room is variable there are no absolutes.
If you plan to finish the floor in the attic and turn the room into a living space however you should always use 3 4 inch.
At least 7 feet in any direction.