Today’s professionally installed roofing systems are the product of years of innovation and engineering advancements. A roofing system is more than just shingles, it is an integrated system of components that work together to keep your roof safe against the elements.
There are three main layers of a roof system. Roof shingles are the most visible layer, but the other components, such as underlayment, ice and water barriers, ventilation, and insulation, all work together to help your roof do its job. As the name implies, Ice & Water Shield create a waterproof barrier on your roof and help to keep moisture out, because it is adhered directly to the wooden roof deck
Stop Water from Reaching the Roof Deck
A roof’s design serves multiple purposes. Your roof provides protection from precipitation and snowfall. Rain falls on the roof’s surface (shingles) and runs down the roof’s slope into gutters, which direct the water away from the foundation via downspouts and drains. Eventually, snow on rooftops melts along the same path.
Unfortunately, many circumstances can disrupt the ideal water flow, and standing water is not a friend to a roof. Water that has pooled on the surface of the roof can cause a variety of problems, eventually penetrating the shingles and entering the home.
Roof Leaks
Certain conditions such as these can lead to roof leaks:
- Clogged gutters can be responsible for two different types of water problems. Water pooling in gutters can back up beneath the shingles, making its way through the fascia and along interior walls. Also, water spilling over full gutters can seep down to your foundation.
- High winds can lift the edges of shingles. Driven rain quickly takes advantage of the openings, infiltrating around nails and wetting the roof decking.
- Ice dams caused by melting snow that refreezes over the eaves block the path to the gutters. Standing water on the roof can eventually seep under shingle edges.
In a perfect world, leaves and seeds will not clog your gutters, winds will remain calm, and snow will fall only once per year. However, this is not the case for many homes and roofs.
What are Ice and Water Barriers?
One practical solution is using an Ice and Water barrier, also known as Ice and Water Shield, below the shingles. Ice and Water Shield adheres directly to the roof decking, these barriers are impermeable, meaning they seal tightly around nails and keep moisture out in all types of weather conditions.
Ice and water barriers provide additional roof protection and can be installed in the following locations:
Valleys: Your roof will have a variety of peaks and valleys based on its architectural design. The rain trickles down the roof and collects in the valleys before entering the gutters. Due to their proximity to water, valleys are more susceptible to its effects.
Eaves: Your roof’s edges are exposed. Winds can catch the shingles’ tips, lifting them and allowing water to enter. Clogged gutters can cause a backup of water.
Roof Penetrations: Whenever you cut into the roof decking, you create an infiltration point for water. Placing an ice and water barrier around chimneys, skylights, and vents aids in securing these vulnerable areas by closing off the gaps around them.
Complete Roof Surface: Depending on where you live, it may make the most sense to install a waterproof barrier beneath the shingles on the entire surface of your roof. During a storm, if you lose shingles, you can rest assured that your roof deck is protected from the elements until repairs can be made.
Ice and water underlayment products create watertight barriers that are not limited to heavy rain and strong winds. There is a reason why “ice” is included in the phrase “ice and water barrier.”
Ice Dams: Winter’s Hidden Leak Potential
When rooftop snow, heat loss from the attic, and temperatures below freezing are combined, the result is an ice dam. More snow and colder temperatures result in a worse outcome.
Consider how an ice dam forms:
- Snowfall accumulates on the roof.
- Snow melts due to heat transfer from the attic to the roof.3.
- The melted water flows down the surface of the roof.
- As the water reaches the eaves, it refreezes, forming a solid ice wall.
- Additional snowmelt accumulates behind the ice dam.
By addressing any of the above issues, you can prevent the formation of an ice dam. While you cannot stop snow from falling or water from flowing downhill, you can prevent snow from melting on your roof.
How to Prevent Ice Dams
By making sure your attic is adequately insulated and ventilated, you can help prevent ice dams from forming in the first place.
Attic Ventilation
One of the primary causes of rooftop snowmelt is improper attic ventilation. The ideal is for the attic temperature to be the same as the exterior temperature.
What causes elevated attic temperatures?
Both air leakage through the ceiling and insufficient or inadequate insulation can contribute to an overheated attic.
Properly positioned ventilation with sufficient net-free space can assist in directing warm air away from the attic, thereby minimizing snowmelt.
Both air leakage through the ceiling and insufficient or inadequate insulation can contribute to an overheated attic.
Properly positioned ventilation with sufficient net-free space can assist in directing warm air away from the attic, thereby minimizing snowmelt.
What is adequate net free space?
Attics should have properly sized and positioned intake and exhaust vents for balanced airflow. Vent sizes are expressed in terms of net free vent area (NFVA), which takes into account any grilles or filters to provide the actual open airflow area for each vent.
Why is inadequate or nonexistent attic ventilation a problem?
Inadequate ventilation that allows the attic to become warm can cause snow to melt, and a lack of ventilation can also allow condensation to form on the interior side of the roof deck, which can lead to wood rot and mold growth.
How can I ensure that my attic is adequately ventilated?
There are numerous methods for ventilating your attic, including:
A balanced soffit and ridge vent system is recommended, but other ventilation options are also viable.
Preventing Ice Dams with Ice & Water Shield
If you live in a region with frequent heavy snowfalls and frigid winter temperatures, ice dams are a seasonal risk. Ice and water barriers are your best defense for preventing water leaks caused by ice dams.
Ice and water barriers are:
- Self-Sealing, preventing water infiltration around nails
- Waterproof, giving added protection to valleys and roof openings
- Self-Adhesive, allowing no space for water migration
Ice and water barriers are also installation-friendly, offering a slip-resistant surface to workers and suitable for cold weather applications.
Did You Know: If you live in an area with an average January temperature below 20 degrees F, your building code probably requires a waterproofing barrier underneath the shingles along the eaves.