Barn Loft Construction
The two most common ways to build a loft in a garage or a barn is to use
Attic Trusses or floor joists with supporting beams underneath. Using
Attic storage trusses during construction is the simplest and most cost
effective way to build a loft. Building loft with floor joists & beams is
a bit more complicated and more expensive.
Attic Truss Loft:
During construction of the building, Attic Trusses are placed on top of walls
(wall headers) and are spaced 24" apart. Attic Trusses are build to
accommodate loft in the center of the building and are built with higher roof
pitch to provide headroom and heavier bottom chord to support the loft area.
Later, when the building is done, loft may be finished with plywood, guard
rails and stairway, or left completely unfinished.
Tip: Due to the fact that Attic trusses are spaced 24" o.c. it's best
to use thicker plywood when building the loft deck. We recommend the use
of 3/4" T&G plywood.
Attic Truss Loft Advantage: Less costly to build, eliminates need for
supporting posts creating a clear span structure, faster construction.
Attic Truss Loft Disadvantages: Loft space is limited to center part
of the building only with inability to have a full loft.
Loft with Floor Joists:
When more attic space is needed such as in a full loft (see image), the loft
must be built with floor joists and roof rafters. On wider buildings
(buildings over 16' wide), floor joists would either need to be supported by
center beam, or combination of beams & posts if constructing a wider building.
Other option you may consider is the use of LVL or TJI Floor joists.
The Advantage of Loft with Floor Joists: More usable attic space and ability to have
your loft build with multiple configurations such as a full loft, half loft, loft over the center part with open
sides or loft over the sides with open center (or any other design you can think
The Disadvantage of Loft with Floor Joists: More complicated and more
expensive to build.
Tip: On a regular 24'x24' car garage, the best way to build a full
loft is to either use TJI Joists or build up a clear span center beam out of (3)
1-3/4"x16" LVL beams
and place 2x10 floor joists on top of walls and the center beam. On wider
buildings, you will need to use combination of beams and posts or TJI floor
joists may be used up to 30' wide buildings. Get more information on TJI Joists
& LVL Beams
from iLevel.com website.
Loft Images (click to enlarge)