issues that result from poor roof ventilation

Issues from Poor Roof Ventilation

In this article, we discuss issues that result from poor roof ventilation and why correct ventilation is critically important to the structure of the home, your energy consumption, your comfort, and your health.

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Are you seeing indications that you may have poor roof ventilation? Issues such as moisture buildup under the roof, peeling paint inside your house, and damage to shingles and roofing materials are problems that become obvious when you have poor roof ventilation. Proper attic or roof ventilation is an essential part of the roofing system. Adequate roof venting prevents many serious problems that occur and get worse without proper venting.

At Allied Roofing Solutions, we include adequate roof ventilation as a standard part of our quality workmanship.

Importance of Roof Ventilation

Importance of Roof Ventilation

We can’t overstate the importance of adequate roof ventilation. Roof ventilation is a system of intake and exhaust vents that provide circulation. This air circulation keeps the inside of your home comfortable. Proper ventilation allows air to flow through your roofing system to keep it functioning in the best way possible.

Having the right amount of ventilation in your attic has a positive effect on the lifespan of your roof system, the comfort and well-being of your family, your future costs for home repairs, and how much you pay for heating and cooling. Proper ventilation in your attic helps address excess heat and moisture that can create major issues in your home. Without correct ventilation, your home is difficult to cool in the summer months and to warm in the winter months.

When Heat and Moisture Build Up

Heat and moisture buildup in an attic cause different problems in hot and cold climates. When it is hot outside, the temperature can rise in the attic, which can warp the roof sheathing and distort and prematurely age the shingles. What if the attic floor isn’t evenly and adequately insulated? In that case, the heat can radiate into the finished living areas, making it more difficult and costly to keep the living space comfortable.

In locations where the temperatures drop below freezing in the winter, warm air will escape into the attic from the heated living space. As the roof warms, the bottom layer of accumulated snow on the roof begins to melt, causing the water to run down the roof. At the edge, the water refreezes into ice and forms ice dams. Subsequently, additional water runoff is blocked and can back up under the shingles.

The formula that roofing contractors use in determining the correct amount of ventilation is 1 square foot for 150 square feet of attic space. For example, if you have 1,500 square feet of attic space, you would need 10 square feet of ventilation to properly release any humidity from the attic:

1,500 (square footage)/150 = 10

Common Problems Caused by Poor Roof Ventilation

Most of the problems caused by inadequate roof ventilation are a result of moisture buildup. Without proper ventilation, moisture builds from the humidity that is trapped in your attic, causing a multitude of issues such as mold and mildew and degrading the roofing material.

damage from heat and moisture

Roofing System Deterioration

The damage from heat and moisture severely compromises the roof’s structural integrity. For example, constant exposure to moisture causes the nails and flashing on the roof to rust. Additionally, the underlayment and shingles will begin to deteriorate. If the damage is extensive, you will need to replace your roof sooner than expected. Cracking shingles or premature loss of granules can be signs of improper roof ventilation.



Delamination occurs when excessive moisture in the attic begins to seep between the roof membrane and insulation. This will cause the roof membrane to pull away from the insulation, resulting in the shingles becoming loose. If a large portion of your roof has loose shingles, then you probably have poor ventilation.

Mold Growth

Mold Growth

Mold growth under the roof shingles can cause them to rot. Mold will also grow inside the attic, which creates stains on surfaces and harms the health of your family. Mold spores cause allergic reactions and trigger asthma attacks. Poor ventilation affects the indoor air quality stemming from moisture that builds up.

Ice Dams and Water Damage

Ice Dams and Water Damage

In the winter months, snow accumulates on the roof. The heat inside a poorly ventilated attic melts the snow, and the resulting water refreezes in the gutter and forms ice dams. Ice dams are ridges of ice that settle along the roof’s edge and prevent water runoff. As a result, water can seep beneath the shingles and cause leaks into the interior of your home, significantly impacting both the structure of the house as well as the rooms inside.

Sagging/Spongy Decking

Sagging/Spongy Decking

When excess moisture begins to seep into the roof decking, the adhesives can dissolve causing the decking to sag between rafters or feel spongy when stepped on. This is a danger for anyone who is on the roof.

Cooling System Issues

Heating and Cooling System Issues

You may notice that your home is not heating or cooling efficiently and your energy bills are increasing when your ventilation is poor. This is because there is very little airflow throughout the house without enough intake and exhaust vents to keep the air circulating. Your heating and cooling system may be working overtime, causing your heating and cooling bills to increase. Your HVAC unit may be too small for the size of your home or it may need to be updated. But, if you are having an issue, it may be due to poor roof ventilation.

Contact Allied Roofing Solutions Today for a Free Estimate

Our knowledgeable and professional team at Allied Roofing Solutions can assess the condition of your entire roof. Contact us today to schedule a free estimate for a roof inspection or to discuss the ventilation system for your home by calling us at   (201) 773-0633 or completing our easy-to-use contact form. If you live in Bergen County, Essex County, Hudson County, Middlesex County, Morris County, Passaic County, or Somerset County, choose Allied Roofing as your preferred source of quality and trusted roofing solutions in New Jersey.