Attic Subfloor Thickness

What s the minimum reasonable thickness for subfloor in my attic.

Attic subfloor thickness.

Viewed 8k times 6. 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. Purchase half inch 1 27 cm thick plywood to act as your flooring.

Ask question asked 8 years 9 months ago. Active 8 years 9 months ago. Attic storage might be a good idea but other issues such as insulation joist spacing and intended usage should be taken into consideration. Attic flooring many new homes around here have trusses 24 on center most of the attic floors are double thickness osb 7 16 when furnaces and water heaters are present.

Achieving greater r values in attics the higher the r value the better the thermal performance of the insulation. You ll need to make sure that the plywood can fit through your attic door. The access on all examples is folding stairs or ceiling scuttles. The recommended thickness of the plywood subfloor is governed by the spacing of the joists.

Measure the plywood and attic door. Attic joists for live loads. Plywood flooring thickness is important for proper weight distribution. It may be easier to lay the sheets cross ways across the joists instead of length wise.

Some experts suggest that 15 32 inch plywood should be standard if the underlying floor joists are spaced 16 inches apart or less but slightly thicker 3 4 inch plywood should be used for joists spaced further apart. Some have single 7 16 osb spanning 24 where the attic is only for storage. Find your zone on the map and then use the chart to determine the level of insulation you need to properly insulate your attic walls floors and crawlspaces. Half inch sheets may be thick enough but 5 8 or 3 4 inches is recommended.

Joist dimensions are only part of the equation. I want to install 4x8 sheets of t g plywood in my attic for extra storage room but there are so many different thicknesses. Keep in mind that a 4 by 8 sheet of flooring will fit the ceiling joists in either direction. Plywood comes in 4 by 8 foot sheets with thicknesses ranging from 1 4 to 1 1 4 inches.

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.