Attic builds are mostly storage platforms and the structural work required to make the space accessible and usable.
01Storage platform — attic floor decking
Add walkable storage surface by laying 3/4-inch plywood across the ceiling joists in the accessible part of the attic. Do not compress the insulation below — use 2x4 or 2x6 sleepers across the joists to raise the platform above the insulation depth. Secure the sleepers with structural screws into the joists, then deck the platform with plywood screwed to the sleepers.
02Attic knee wall storage
Knee wall alcoves — the space behind the knee walls in a finished attic — are built out with doors and shelving. Frame a simple door opening in the knee wall, hang a door, and build shelving in the alcove. This converts dead space into real storage without affecting the finished floor area.
03Dormer window seat
A dormer window seat is a plywood box built to the height of the windowsill — typically 16–18 inches — spanning the dormer width. Build the box from 3/4-inch plywood, face it with trim matching the room, hinge the top for access to interior storage, and pad and upholster the top surface. A dormer window seat with storage is the most-used piece of furniture in most finished attics.
04Built-in desk — sloped ceiling
A built-in desk under a sloped ceiling uses a wall-mounted ledger as the desk surface support. Mount a 2x6 ledger into the wall studs, level at desk height. Cantilever the desktop from the ledger or add a single leg at the outer edge. The sloped ceiling above is the natural bookshelf — add floating shelves up the slope following the ceiling angle for a fitted look.
Marcus Webb is a general contractor and home maintenance writer based in Columbus, Ohio. He writes about the repairs and installs that come up every year in every house — the practical, repeating work that keeps a home livable.