Roof Insulation Guide: Stop Energy Loss & Ice Dams

Is Your Money Escaping Through Your Roof?

Proper roof insulation is the difference between a cozy home and a freezing one. In Central Illinois, where winter temperatures frequently drop below zero, your attic insulation is the primary defense against skyrocketing heating bills.

If you have noticed icicles hanging from your gutters or rooms that never seem to get warm, the culprit is likely hidden in your attic. This guide explains the science of roof insulation, why “R-Value” matters for Peoria homeowners, and how to stop dangerous ice dams before they start.

Why Roof Insulation Matters in Zone 5

According to the U.S. Department of Energy, Illinois falls into Climate Zone 5. This means our homes require significantly more insulation than homes in the south.

When roof insulation is too thin or settles over time, two things happen:

1. Heat Loss: Your furnace works overtime to pump heat into the house, but that heat rises and escapes directly through the attic.

2. Ice Dams: This is the most dangerous result. Heat escaping through the roof melts the snow on your shingles. That water runs down to the cold gutters and refreezes, creating a dam. This dam forces water to back up under your shingles and into your walls.

The “R-Value” Explained (Simply)

You will hear contractors talk about “R-Value.” Don’t let the technical term scare you.

• R-Value = Resistance. It measures how hard it is for heat to pass through the material.

• The Illinois Standard: In our area, the Department of Energy recommends an attic R-Value of R-49 to R-60.

• The Reality: Many older homes in Peoria only have R-19 (about 6 inches of old fiberglass). That is not enough to stop the winter cold.

Types of Insulation We Recommend

Not all roof insulation is created equal. Here are the three most common types we see in Central Illinois homes:

1. Fiberglass Batts

These are the pink or yellow rolls you see in home improvement stores.

• Pros: Affordable and easy to install in open spaces.

• Cons: If not cut perfectly, they leave gaps. They also don’t seal air leaks very well.

2. Blown-In Cellulose

This is made from recycled paper treated with fire retardant. A large hose blows it into your attic, creating a fluffy blanket.

• Pros: It fills every nook and cranny, covering wires and pipes perfectly. It has a higher R-value per inch than fiberglass.

• Cons: It settles over time, so you may need to “top it off” every 10-15 years.

3. Spray Foam (The Gold Standard)

Spray foam expands to fill cavities and hardens into a solid layer.

• Pros: It provides the highest R-value and creates a perfect air seal, stopping drafts completely.

• Cons: It is the most expensive option and requires professional installation.

Signs Your Insulation Needs an Upgrade

You don’t always need to crawl into the attic to know there is a problem. Your house will tell you:

• Fluctuating Temperatures: Is your upstairs 10 degrees hotter than your downstairs in the summer? That is a sign of poor roof insulation.

• High Energy Bills: Compare your bills to a neighbor with a similar-sized home. If yours are 30% higher, your attic is likely the thief.

• The “Melt Pattern”: Look at your roof after a light snow. If you see bare patches where the snow has melted (while your neighbors’ roofs are still white), you are losing heat.

Save Money and Protect Your Roof

Upgrading your roof insulation is one of the few home improvements that pays for itself in lower utility bills.

At SNS Roofing, we look at the “whole system.” We don’t just check your shingles; we check your attic ventilation and insulation levels to ensure your roof system lasts as long as possible.

Stop heating the neighborhood. Contact SNS Roofing today for a free attic inspection and learn how we can improve your home’s efficiency.