Routine attic maintenance is an essential part of whole-home comfort and energy efficiency. Knowing more about your home’s attic anatomy and what each part does, helps homeowners make better decisions when it comes to attic and roof maintenance, repairs, or replacement.
Attic Anatomy 101:
Here is a list of the average home attic's general parts and pieces.
- 1: Roof Rafters or Truss
- 2: Rafters
- 3: Trusses
- 4: Top of the Home's Envelope
- 5: Attic Insulation
- 6: Ventilation
- • Solar vents
- • Turbine vents
- • Power vents
- • Ridge vents
- 6: Stairs and Access Points
- 7: Air Sealing
- • Recessed lighting
- • Holes drilled for wiring either during original construction or for aftermarket work by electricians, home A/V techs, HVAC work, etc.
- • Gaps around attic hatches or drop-down attic stairs/ladders
- • HVAC ductwork penetrations and grilles
- • Attic windows or vents
- • Sealing up air gaps means no more drafts and reduced energy bills
Depending on when your home was built, or the home’s architectural style, it was framed using roof rafters or trusses.
Rafters are built using engineered lumber that is laid one piece at a time on-site - a reason they’re also referred to as a “stick framed roof.” Roof joists used to frame the base of the rafters are sturdy, like a floor, so are better able to bear weight if you decide to convert your attic into usable space later on.
Trusses are a more contemporary version of rafters, using prefabricated systems. Trusses are a standard these days. They use a system of triangular “webs” to frame the roof while also tying the home's exterior walls together. Trusses don’t typically leave an expanse of open space that rafters do, and their bottom chords aren’t designed to bear weight. If your home has trusses, odds are some type of reinforcement is necessary for future attic conversions.
We speak of the exterior layers of the home (foundation, exterior walls, attic/roof, windows, exterior doors) as the home’s envelope. This includes the attic space, with its combination of insulation, ventilation, and potential penetrations from other home systems or features.
Attic insulation is one of the most important features in your home when it comes to comfort and energy efficiency. Inadequate or out-of-date insulation makes for a home with more drastic temperature fluctuations, unstable humidity levels, and higher-than-normal energy bills - especially around peak hot and cold seasons.
While we recommend scheduling professional attic inspections every two to three years, homeowners can perform DIY insulation inspections to make sure all is well. Replacing or updating damaged insulation makes a noticeable difference in home comfort and energy savings. There is a wide range of insulation options out there these days. While fiberglass bats are still a standard, homeowners focused on sustainable or more eco-friendly options are migrating more towards spray foam, wool, and foam board options, which are less susceptible to moisture and after-market construction work - not to mention highly energy efficient.
The roof and attic are partners when it comes to keeping your home comfortable year-round. Besides professional installation, they rely on adequate insulation and ventilation. The home’s ventilation systems are divided into active and passive categories, and several options live in your attic. Some of the most common of these are:
Soffit vents (these are under the eave of your home and direct fresh air into the attic/home) Newer homes are built with adequate ventilation in mind. If you live in an older, it’s worth scheduling an inspection to see if your attic has the quality of ventilation required for optimal efficiency and air quality.
If your attic is used for storage or additional living space, odds are you use a ladder or stairs to access the space. These are also considered part of the attic anatomy. Choosing the right access method optimizes user comfort and safety and simultaneously impacts overall attic energy efficiency.
While not necessarily a physically obvious component of attic anatomy, air sealing is part of the efficient home envelope equation. Most homeowners focused on the visible portions of the home are good about updating or replacing weather stripping or caulking around window frames, exterior penetrations, door frames, and so on.
However, the attic needs to be sealed as well. In many cases, the maintenance performed around the visible and easily accessible portions of your home is completely undermined if you aren’t paying the same level of attention to the attic. We always perform a once-over and update air sealing before replacing insulation in a client’s home or business. If you are a DIYer, we recommend visiting EnergyStar.gov’s Attic Air Sealing Project page to learn more about the process.
If you opt for DIY air sealing, pay special attention to “sneaky” areas that often contribute to heat/cooling loss as a result of escaping air. These are: