See how intake and exhaust work together, what to ask during an inspection and why vented and unvented attics need different plans.
Count airflow paths, not just roof vents. A conventional vented attic needs a coordinated intake and exhaust arrangement. A sealed, unvented roof assembly is a different design and should not be modified by simply adding vents.
How a conventional vented attic works
The cutaway shows the air channel above the insulation, not through it. Baffles keep the intake path open. Actual vent placement and net free area must be sized for the building and selected products. Source: Pacific Northwest National Laboratory. View original detail.
| Part | Inspection question |
|---|---|
| Intake | Are openings present and unobstructed by insulation, paint or debris? |
| Exhaust | Is the selected system compatible with the intake and attic layout? |
| Air path | Can air move through the intended space rather than a blocked pocket? |
| Moisture sources | Are indoor air leaks, bath exhausts or roof leaks contributing to the problem? |
| Roof penetrations | Are vent flashing and surrounding shingles properly detailed? |
Not every pipe or hood is attic ventilation
Plumbing vents and appliance exhausts serve different purposes. Identify each opening before deciding whether the attic needs more ventilation. Our San Antonio repair photographs show roof penetrations and flashing details; they do not establish the airflow performance of the attic.
See the San Antonio vent and flashing repair
Spray foam and radiant barriers need a separate review
Tell the inspector if foam is applied below the roof deck or if a radiant barrier is present. A properly designed unvented attic may be intentional. Insulation, air sealing, moisture control, equipment and shingle requirements must be evaluated together. Do not block existing vents or cut new openings based on a generic diagram.
What a useful assessment should explain
Whether the assembly is intended to be vented or unvented.
The observed intake, exhaust and obstructions.
Evidence of moisture or leakage and possible sources.
The proposed products and any related insulation or HVAC coordination.
Request a roof inspection or written estimate
Source: TAMKO ventilation literature and technical notices
Source: US Department of Energy: unvented conditioned attics
Identify the vent: a photo guide
These GAF product photos show what different vent types look like before installation. They are identification examples, not a recommendation to combine every type on one roof.
Ridge exhaust
A low-profile vent along the peak, usually covered with ridge-cap shingles.
Box / slant-back exhaust
Individual static roof vents. Count the published NFVA for the specific model.
Wind turbine
A rotating ventilator driven by wind. Output changes with conditions.
Electric exhaust fan
A powered roof fan. Its required intake must match its model and airflow rating.
Solar exhaust fan
A fan powered by a solar panel. Sunlight and the model affect operation.
Soffit intake
A screened opening beneath the eave. Insulation must not block its path.
Rooftop intake
A low-roof intake option where the selected product and roof design allow it.
Gable wall louver
A vent in the end wall. Its role depends on the overall system and wind direction.
Compare vent ratings and calculate intake needs
A round roof vent near intersecting shingle roof slopes. A photo cannot establish the vent’s rated airflow.
Prepared by Barnes N’ Roofs, New Braunfels, Texas. Reviewed September 18, 2026. Product availability and written manufacturer terms control.
Turn vent counts into an airflow plan
For a conventional vented attic, compare the usable intake and exhaust capacity, not just the number of openings. Owens Corning describes a balanced intake and exhaust system. Ask the contractor to document the selected products, their net free ventilating area and the pathway between them.
| Record | What belongs in the assessment |
|---|---|
| Attic arrangement | Vented or intentionally unvented. |
| Intake | Product rating and visible restrictions. |
| Exhaust | Product rating and planned layout. |
| Air path | Any blocked soffits or insulation obstructions. |
Owens Corning ventilation components