A home's style and vintage often dictate to what extent an attic can be used for attic storage. Victorians and pre-1970's Colonials offer the best third-story space due to the steeper pitch of their roofs. Newer two-story homes, ranches, and raised ranches have the least amount of attic storage space, mostly because the engineered roof trusses used in new construction greatly compromise roof pitch. In fact, newer homes often allow for little more than crawl-space storage.
Even without traditional attic storage space, Cape Cods and bungalow-style homes offer creative opportunities for second-story storage. Shed dormers are found or created where the roof extends beyond the dominant roofline. These spaces can provide storage units the size of a large closet or small room. Storage alleys are commonly found in homes of this style. Known as knee-walls, they run along the exterior wall, beneath the dormer or perpendicular to it, and can be accessed by doors cut into the wall. Because of the angled ceiling, however, these alleys offer little or no headroom but are ideal for shelves and stacking storage. Shed dormers can also be constructed to lessen the slope of a ceiling and extend the storage capabilities of a spare room or third-floor attic.
No full attic is completely safe for storage unless it is properly ventilated and insulated. Ventilation and insulation work hand-in-hand to reduce humidity and prevent drastic swings in temperature during the summer and winter months.
While goods unaffected by temperature can be stored in an uninsulated attic, all attic storage areas should be properly ventilated. Ventilation prevents excessive heat and humidity build-up. It can take place naturally, provided the necessary vents are present. In this case, cooler air enters the attic by way of vents located near the eaves. Warm-air convection then causes the hotter air to escape through vents in or around the roof.
Mechanical ventilation uses an electric fan to draw in fresh air and suck out the old. The fan operates automatically any time the heat in an attic reaches 100 degrees. Before you have an attic fan installed, make sure that it has a firestat or automatic shutoff feature. Since they cause increased air currents that can fuel house fires, attic fans need shutoff sensors that kick in should temperatures increase dramatically. Some attic fans are even equipped with a humidistat that will activate anytime the humidity level climbs above 70 percent.
Insulation acts as a buffer by slowing down the transfer of heat between second-story living space and the attic. Most attics have insulation between the floor joists, but additional insulation is recommended if you intend to use the attic for long-term storage. Insulation is rated for efficiency, known as the R-value, and can be tailored to suit the optimal insulation standards for your region. Except in the driest of climates, moisture buildup is a concern in insulated attics. Vapor barriers, air space, and venting all offer possible solutions to the problem, but it's best to explore your options before tackling any insulation installation.
Of course, no attic is fully functional as storage space if the ceiling joists above your second-story can't sustain a weight-bearing floor. A floor can be installed, but not without first beefing up the joists. If the only means of access is through a hatch in a bedroom closet, you may also want to construct a fixed staircase or install a fold-down ladder.
Efficient Use of Space
Attic architecture presents interesting options for wall storage. The gable walls provide the greatest surface area, perfect for shelving or custom cabinetry. Under-eave wall space can be transformed by constructing a knee-wall. Built out away from the exterior wall, the knee-wall cuts off the angular slope of the eaves at its lowest point. A four-foot knee-wall can provide a level shelf space to support boxes, while doorways cut into the wall provide access to under-eave storage. Shelving can be attached to the exterior wall behind the new knee-wall for easy organization. A durable wardrobe bag can hang from the collar beam that runs perpendicular to the rafters, while the space between collar beams is used to support a platform for lightweight storage. Hanging shelves can be suspended from the rafters for compartmentalized storage of smaller goods.
When organizing an attic, resist the temptation to stack heavy boxes on top of furniture so as not to weaken the furniture joints. Stacked boxes make it more difficult to check for pests, or hidden damage to your structure or wiring. Whether your storage space is attic, dormer, crawl space, or alley, take the time to create an inventory map. Along with it, keep a schedule for regular checks of furnishings, boxes, and infrastructure, so that your prized possessions stay in prime condition.