What is a Soffit: Understanding Its Key Role in Proper Home Design

By: Carrie Whitney, Ph.D.  | 
Soffits on a house
Soffits are part of the eaves, the structure of the roof that overhangs the exterior walls. Sometimes soffits are simply decorative, but they also serve many structural purposes as well. cruphoto/Getty Images

An important but often overlooked construction feature, soffits help protect your home from all sorts of invaders — think everything from mold to squirrels. Although they do this while providing an attractive transition from the roof to the exterior walls of a home, soffits are clearly more than just decorative elements.

So what is a soffit, exactly? They provide a necessary function, yet not all homes have them. Where are they located on your home and what are they good for? We'll answer all of these questions today.


What Is a Soffit?

Technically, a soffit is any material that makes up the underside of a part of your house, including ceilings, stairs, and cornices. Older homes might feature soffits as a decorative element, while other structures use soffits to hide things like structural beams, HVAC ducts, or plumbing.

There are interior and exterior soffits, but we'll be focusing on soffits for the home's exterior. Those are the most common type, and they are located on the roof's overhang, at the edge of the eave.


The eaves are the part of the structure's roof that overhangs the exterior walls, explains Justin Larrison, remodeling consultant and co-owner of Small Carpenters at Large, a design/build firm that's been in business for more than 40 years in Atlanta. Eaves are made up of two primary components: fascia, the outer vertical cladding that gutters attach to, and the soffit, the horizontal cladding or framing that encloses the underside of the eave.

Finding Your Home's Soffit

Your home can have an eave without being enclosed by a soffit, but it can't have a soffit without an eave. Older homes and some new construction homes with insulated roofs have exposed — or open-rafter — eaves where the rafters of the eaves are visible. In that case, soffits are not necessary. Other homes may have eaves that do not extend beyond the exterior walls. In these cases, there is no place for a soffit.

According to Qualityedge.com, the easiest way to tell if your home has soffits is to walk around it while looking up at the roof. If you can see the underside of the eaves, but you can't see the rafters, your home has soffits. The soffits will most likely be constructed of short planks.


Diagram of how a soffit attaches to the rest of a house.
This diagram shows how the soffit attaches to the fascia and the exterior wall, and how the soffit helps air flow through a home's attic to help keep it properly ventilated.
Wikimedia/(CC BY-SA 4.0)

What's the Purpose of Soffits?

Soffits have an important job on the outside of a house. They protect the underside of the eaves from moisture and rot. Moisture can cause big problems, not only to the eaves, but also to the attic. In fact, soffits can be essential to a properly vented attic.

Vented Soffits

"Traditional attics are unconditioned and uninsulated, requiring air circulation so they don't overheat during the summer or trap cold moist air during the winter," Larrison says via email. "During the hot months, air moves up from the vents in the soffit, through the attic, and out either a ridge vent at the top of a roof or through vents spaced properly along the upper part of the roof."


This benefit doesn't only apply during hot summer months. The reverse happens during cold months, and in all seasons, this ventilation is vital.

"Overheating can shorten the life span of materials, mainly roof shingles and add to energy costs, while trapped moisture creates a breeding ground for the dreaded 'M' word: mold," Larrison says.

Protecting Attic Space

Soffit vents are proficient at preventing mold growth. Additionally, a vented soffit helps keep unwanted intruders like insects, pests, and birds out of the attic, too.

Despite their benefits, not all homes need soffits. For example, an attic can be ventilated by gable vents — those cute features that look like louvered shutters on the exterior face of an attic. Homes employing this look typically have insulated attics, negating the need for outside air circulation, which is the main purpose of soffits, Larrison explains.


Common Soffit Materials

Historically, a wood soffit could feature a variety of styles like simple plank, wainscot, or beaded, according to Qualityedge.com. Now, there are many additional materials used, and it isn't uncommon to see an aluminum soffit or vinyl soffit in most neighborhoods. Although these newer options may mimic the look of traditional wood, they offer the benefit of durability and can be vented to help with airflow.

Of course, various wood grain finishes are still optional. Beyond soffit material, many unique soffit designs are also available, incorporating colors that coordinate or match the style of the home.


"Not every home is the same and soffits are no different," says Larrison. "Materials can range from beautifully stained wood to low-maintenance vinyl." They can be open, vented, fully enclosed or custom-tailored to the local weather. You can even install soffits that are ready to withstand storms.

Eaves with gutters on a white house.
This image of an eave shows how the gutters attach to the fascia and the soffit, which is the horizontal cladding or framing that encloses the underside of the eave.
michael1959/Getty Images


How to Maintain Soffits

Just like every part of your roofing system, soffits must be inspected and maintained, explains Larrison, who recommends giving your soffits a good once-over annually. The same goes for your roof trusses and open eaves, ensuring overall structural integrity.

"Peeling paint, separation between materials, and mildew or mold spots are typically the first signs that the soffit or eave need maintenance or repairs," he says.


Keeping the roof and gutter free of debris is the best way to prevent damage to soffits and fascia. Vented soffits can be cleaned with compressed air to keep dirt and debris from clogging the openings, according to MHC Gutters. Other maintenance includes ensuring the soffits are clear of insect nests, washing them with a mild detergent to get them clean without damaging their coating, and keeping them sealed and painted.

"All homeowners should take some time to educate themselves on their home, so they know what their specific situation is, how to maintain, and what signs to look for when something isn't working correctly," says Larrison. "With an abundance of information at our fingertips, investing some time in education now can save a lot of money and stress down the road."