A home's attic is a great place to store seldom used items, or even to refinish into a livable space. If the homeowner intends to use the space for such purposes, however, the space will need an attic floor that is stable and well-constructed. The first and most important step in installing an attic floor is determining how the space will be used, as this will usually dictate what type of flooring is necessary. Insulation will also need to be installed before any flooring is laid down; this will help make the attic space more comfortable and livable, but it will also help regulate temperatures in the floors below.
The attic space is likely to have several floor joists running across the length of the house. These joists will provide the support for the attic floor once it is installed, so it is essential to do a thorough inspection of these joists to ensure they are strong and undamaged. If any of the joists are damaged, they will need to be repaired before any flooring is laid down. Sometimes a joist will need to be replaced entirely to ensure the safety and stability of the entire floor.
Once the joists have been inspected, the builder will need to lay down sheets of plywood to act as the base or subfloor for the attic floor. If the access to the attic is very narrow, it may be necessary to cut down the sheets of plywood into narrower strips that will fit more easily through the attic hatch or door. The plywood sheets should be screwed or nailed to the joists; the nails or screws should be set at regular intervals along the length of the sheets. Nails are less expensive than screws, but screws will ensure the plywood boards do not loosen or warp over time. This is especially important if the attic floor will see frequent use.
Once the plywood is laid down, the builder can consider further insulation options as well as flooring options. Aluminum insulation can be applied to the subfloor to act as a radiant barrier, thereby helping regulate temperature more effectively. This type of insulation comes in a roll and is laid out flat across the plywood. Then finished floor panels can be laid on top of the aluminum. If insulation already exists beneath the subfloor, the finished flooring materials can simply be laid directly onto the plywood. If finished flooring materials are not necessary, the plywood can act as the floor itself.