Attic storage is possible in most houses for stashing away a few boxes and empty suitcases. Before you take advantage of this storage space, take some time to assess the potential space—and the potential problems—your attic may hold in store for you.
Storage in an Attic With Roof Leaks
Roof leaks are a problem no matter what plans you have for attic storage. Even a small leak can lead to serious trouble. Here are some things to check for:
- Stains on the ceilings beneath the attic, which can be a surefire indication of a leak in the roof.
- Bathroom vent fans that terminate in the attic. Vent fans pull warm, moist air from your bathroom, and you don't want that in your attic. Reroute the fan duct to the outdoors, either through the roof or a wall.
- Rot, stains or other signs of water damage on the underside of the roof sheathing.
- Signs of leaks around chimneys, vent pipes and other objects that penetrate the roof.
- Condensation on the roof sheathing and framing. This may indicate the need for additional ventilation in the attic rather than a leak.
The floor structure of an attic is also the framing for the ceiling beneath it. This is made up of ceiling joists, typically 2x6 or larger boards. As long as they are not damaged, the joists should be strong enough to allow you to move around in the attic for an inspection and to provide storage for typical boxed items. But they may not be adequate to support the weight of multiple people, furniture, and heavy stored items.
Before you start moving around the attic, however, think hard about what you will be stepping or crawling on. The joists should support your weight, but the space between them almost certainly will not. The safest way to move around an unfinished attic is to create a catwalk (or walking platform) by attaching some 1x6 or 1x8 boards or strips of 3/4" plywood to the joists with screws (don't use nails because the hammering might disturb the drywall or plaster ceiling below).
As a very general guide, if the joists are only 2x4s, don't plan on storing much in the attic other than very lightweight items; think empty boxes and suitcases. If they are 2x6, you can probably get away with some boxes filled with relatively light stuff. Joists that are 2x8 or larger can likely support more weight. But in all cases, the strength of the floor is based not only on the size but also the span of the joists, i.e., the distance between the supports below. These include the exterior walls below the floor as well as some of the interior walls that run perpendicular to the joists, called load-bearing walls. You may want to discuss the suitability of your attic framing with a professional contractor.
If you determine that your attic floor structure can't hold what you'd like to store, it's possible to beef up the floor framing by adding more or larger joists. You can then cover the joists with plywood or an OSB subfloor to create a nice, continuous floor surface.
Traditional stick-framed roofs are composed of rafters running from the ridge (at the roof peak) down to the walls. This framing style typically provides the most open space in an attic. Newer truss-framed roofs are made with prefabricated trusses. Trusses are like big, structural triangles that have angled top pieces that serve as rafters, horizontal pieces that serve as floor joists and interconnecting web pieces that give the triangle strength. The webs usually don't leave much room for storage. Unfortunately, you can't cut or remove any of the webs because it weakens the truss. Some roofs are framed with special “storage trusses” that leave an open, central space suitable for storage.
Access to Attic Storage
If you want to use your attic on a regular basis or to store large items, you may need to enlarge the access opening and install an access ladder or drop-down stairs. If the attic has the potential to become a regular living space, talk with a contractor about adding a fixed stairway.
This is where dreams of adding new living space in an attic are often abandoned. Building codes typically require that a finished space have a ceiling height of 7 feet 6 inches over at least half of the available floor space. So if the distance from the roof ridge to the floor joists isn’t at least 9 feet, you probably won’t be able to meet the code requirement unless you add a dormer.
But you don’t need to worry about building codes for creating simple storage space or a place to sit and read. Either way, you do need to be conscious of the roofing nails that may be poking through the underside of the sheathing. A hard hat is a handy bit of protection to have when looking around an unfinished attic. If you want to spend some time up there, however, consider adding a finished ceiling.
The Temperature for Attic Storage
If your house is insulated, there’s a good chance that the attic is outside of the home's thermal envelope, the boundary of insulation surrounding the heated/cooled living space. If so, don't store temperature-sensitive items in your attic. Adding insulation to the walls and ceiling won't keep an unheated attic substantially warmer in cold weather (or vice versa in summer), and it can create problems with attic ventilation if not done properly. Ventilation is critical to the health of your home, so make sure your storage plans won't affect the existing ventilation system. For example, don't block any vents to protect your stored items from cold air. Instead, move the stored items away from the vent or consult a building professional to discuss alternatives.