We are asked all the time about attic ventalation. Should we install an attic fan with our ridge vent? What are those square vents on our roof? When it comes to attic ventilation, it isn’t a choice, it’s essential. Not just to prevent moisture and heat buildup, but also to extend your roof’s lifespan and save on energy bills.

Here are five common installation mistakes many homeowners and contractors make (and how to dodge them).

1. Incorrect Placement of Intake & Exhaust Vents

Your ventilation system requires both intake vents (usually beneath the eaves/soffits) and exhaust vents (typically along the ridge). Mixing these or misplacing them along the same roofline disrupts airflow, leading to hot spots, moisture buildup, and accelerated roof wear .

2. Mixing Intake and Exhaust Vents Together

Avoid combining intake and exhaust vents in the same section of the roof. Intake vents should be low and exhaust vents high, so air can flow properly and protect your attic. When they're too close, air just escapes without circulating, making the system inefficient.

3. Under‑Ventilating (Not Enough Vent Area)

To meet building standards like FHA and IRC, you generally need at least 1 sq ft of vent area per 150 sq ft of attic floor space—ideally split evenly between intake and exhaust. Skimping on vent coverage starves the attic of airflow and leads to problems like trapped heat, moisture, mold, and ice.

4. Blocked or Obstructed Vents

Even a well-designed system fails if vents are clogged. Debris, nesting animals, or misapplied insulation can all block airflow. Regular inspections are essential to ensure vents stay open and working.

5. Skipping the Overall Ventilation Strategy

The most significant error isn’t one ventilator—it’s failure to design a comprehensive system. Climate zone, attic shape, and insulation all matter. You need a balanced intake-exhaust system, tailored to your home’s specifics for maximum efficiency and roof health.

Why It Matters

• Temperature control: Proper airflow helps prevent attic overheating in summer.

• Moisture reduction: Limits mold risk and shield structures from rot.

• Energy savings: Reduced burden on HVAC systems.

• Prevents ice dams: Stops warm attic air from melting snow and freezing at eaves .

• Extends roof life: Cooler, drier attics preserve shingles and decking.

  
  

✅ Best Practices Checklist

1. Place intakes low and exhausts at the peak—keep them apart.

2. Calculate vent area with the 1:150 rule, split evenly.

3. Inspect for clogs: debris, nests, or insulation buildup.

4. Design holistically, considering your climate, roof type, and insulation.

5. Consult a professional if you're unsure—building codes vary.

   
   

Final Thoughts:

Effective attic ventilation isn’t about adding vents—it’s about creating a balanced system that works together. Proper intake and exhaust placement, correct vent sizing, and routine maintenance ensure a healthy attic, lower energy costs, and a longer-lasting roof. If you’re still not sure about what type of ventalation best suits your home, give us a call at 609-457-3959. Fives Contracting is always happy to help!