Most homeowners think of a roof as simply “the shingles.”
In reality, an asphalt roofing system is made up of many different components that all work together to protect your home from water, wind, snow, heat, and Colorado’s extreme weather conditions.
When one part of the system fails, it can affect the performance of the entire roof.
Understanding the different components of a roofing system can help homeowners make better decisions during roof replacements, inspections, and insurance claims.
At Excel Roofing, one of the most common things we see is homeowners not realizing how many layers and details exist underneath the shingles themselves.
Roof decking, sometimes called roof sheathing, is the wooden surface installed over the roof framing.
This is the foundation that the entire roofing system is attached to.
Most residential roofs use:
The decking:
If the decking becomes rotted, soft, or water-damaged, it may need to be replaced before a new roof can be installed.
Often yes, if it is still structurally sound.
However, during roof replacements, damaged decking is commonly discovered after the old shingles are removed.
Underlayment is installed directly over the decking and underneath the shingles.
It acts as a secondary moisture barrier if water gets underneath the shingles.
The two most common types are:
Today, synthetic underlayments are much more common because they are:
Underlayment helps protect against:
Even though shingles are the primary waterproofing layer, underlayment provides critical backup protection.
Ice and water shield is a self-adhering waterproof membrane installed in vulnerable areas of the roof.
In Colorado, this is especially important because of snow, freeze-thaw cycles, and ice dams.
Common locations include:
Unlike standard underlayment, ice and water shield seals around nails and creates a waterproof barrier designed to prevent leaks from ice backup and standing water.
Step flashing is metal flashing installed where a roof meets a vertical wall, such as:
This is one of the most important waterproofing details on a roof.
Step flashing redirects water away from wall intersections and onto the shingles below.
Without proper step flashing, water can easily enter behind siding or walls and create hidden leaks.
Unfortunately, improper flashing is one of the most common roofing installation problems seen during inspections and leak investigations.
Roof ventilation is one of the most misunderstood parts of a roofing system.
Many homeowners do not realize roofs are designed to breathe.
Proper ventilation helps:
Poor ventilation can lead to:
Most building codes follow a ventilation ratio of:
1 square foot of net free ventilation area for every 150 square feet of attic floor space.
In some situations, the ratio may be reduced to:
if certain balanced ventilation conditions are met.
Roof systems work best when intake and exhaust ventilation are balanced.
Typically:
This creates natural airflow through the attic.
Ridge vents are installed at the peak of the roof and allow hot air to escape.
These vents pull cooler air into the attic near the lower portion of the roof.
Together, they create continuous airflow.
Starter shingles are installed along roof edges before the main shingles are applied.
They help:
This component is small but extremely important during high wind events.
Field shingles are the primary visible shingles covering the majority of the roof.
These shingles provide:
Different shingles offer different:
Hip and ridge shingles are specially designed shingles installed along:
These areas experience:
Hip and ridge shingles are thicker and designed to properly flex over roof transitions.
Skylights can dramatically improve natural lighting inside a home.
However, they are also one of the more technically sensitive parts of a roofing system.
Skylights require:
Improper skylight installation is a common source of roof leaks.
Not necessarily.
A properly installed high quality skylight can perform very well for years. The key is proper installation and flashing details.
One of the biggest misconceptions homeowners have is thinking shingles alone protect the home.
In reality, a roofing system is made up of many layers and components all working together.
A high quality roof depends on:
Even premium shingles can fail early if the rest of the roofing system is poorly installed.
At Excel Roofing, educating homeowners about how roofing systems actually function is a major part of helping people make informed long term decisions about their homes.