What is a Soffit?

soffit along underside of roof

What is the purpose of a soffit on a house?

Are you considering new siding for your home? You’ve probably realized that there are several different factors to be considered with this project, like including replacing the fascia and soffit. Both are essential to your home’s well-being, yet, because they aren’t easily seen or not aware of what their purpose is for a home. 

Fascia and soffit are typically replaced when new siding is installed, they are a trio that shouldn’t be separated so that all three match. Having the fascia and soffit installed at the same time as the siding will ensure that they are doing their job in providing insulation for your home. 

The soffits are more than the finishing touch to the roofing and siding of your home. Their purpose is to ventilate the attic to keep the rafters from rotting and prevent moisture damage to the attic and roof. The addition of the fascia boards is as important as the soffit as they protect the rafters and trusses ends by becoming a barrier against the elements.

Is soffit part of the roof?

Yes, and is typically matched with the siding. The soffit is located on the underside of the eaves, sometimes referred to as the roof overhang. Without the soffit, the eaves or overhang would be exposed to the elements and the aesthetics wouldn’t be as consistent with the siding. 

Do soffits lead to attic?

We know that attic ventilation is essential to a roof for several reasons: 

  • Keeps the attic cooler in the summer, lessening the strain on the air conditioner.
  • Reduces moisture in the attic from heat building up in the winter.
  • Eliminates  water condensation under the roof, preventing mildew, mold, and rot.

There are soffit vents that go with the rest of the soffit to provide the eaves ventilation. The eaves direct the fresh air from the soffit vents to the attic to do the things we just listed. 

For the soffit vents to work their best, they need other ventilation in the roof to pull that fresh air through. Some homes have roof vents on the roof’s peak either as individual roof vents, gable vents, or hip roof ventilation. 

Does soffit need to be vented?

Yes, for proper ventilation of the attic, soffit vents work in conjunction with the other vents as described above, pulling fresh air in through the eaves to the attic. This keeps the air circulating in the attic under the roof decking. 

How big should soffit vent holes be?

This can vary based on local building codes. Some requires small holes drilled in all the way around in the soffit. Others require 3” holes with mesh covering. If you are having your siding, soffit, and fascia installed by a professional, they will either know the requirements or where to get that information. If you are doing your own installation, check with the local governing offices. 

How much vented soffit do I need?

The general theory is 1 square foot for every 150 square foot of attic area. The ideal placement is for half the vents to be installed in soffits around the lower part of the roof for attic circulation. There are  different soffit vent types: 

  • Continuous
  • Circular
  • Perforated

For rectangular or square vents, multiply the length to the vent space width in inches. Now divide by 144 to for square footage conversion. For instance, a 6″ x 12″ vent is equal to 72 square inches divided by 144 =  0.5 square foot per vent.

How do I know if my soffit vents are working?

When new aluminum or vinyl soffits are installed  on a home where the siding already exists, the contractor will often cover the soffit vents. Sometimes, the contractor will install ventilated soffit sections but fail to cut out any material existing behind the vent, essentially keeping the soffit vents to work as they are intended.  

You can check your soffit vents by looking into the vent slots with a flashlight. If you see boards or insulation, you need to access the attic and remove the insulation covering the soffit vent. If there are boards blocking the soffit, you need to cut/drill holes into any board so that the soffit vent is getting air.  

underside of roofing system

How do you tell if attic is properly vented?

During the summer, heat buildup is reduced when there is good attic ventilation and in the winter, when moist, warm air seeps into the attic from below, good ventilation pulls it up and out of the house. These are how the attic stays dry and the possibility of ice dams are minimized. Four indications that your attic isn’t ventilated adequately:

  1. If you do not see any vents on the eaves and the roof, your attic is lacking enough ventilation. This can be added easily by an experienced roofing or siding professional. Many roofs have low profile roof ridge bents at the peak, or you may have gable vents. 
  2. On a sunny day when its warm, touch the ceiling and if it is hot, your attic isn’t ventilated enough. 
  3. On a cold, wet winter day, if there are thick ridges of ice on the eaves, your attic is inadequately ventilated. 
  4. Inspect the attic with a flashlight and look for any dampness, frost, or moisture. If you find any of that, your attic has insufficient ventilation. 

Once you have your siding, soffit, and fascia installed, can you pressure wash soffit? The answer to this is yes, but with caution.  Never use a high powered water pressure. This can bust through the soffit and create a lot of damage in the attic and behind the siding. Call (410)-288-1633 today for your soffit installation in Baltimore, MD.