Seal Out Roof Leaks with High Temp Ice and Water Shield

Roof leaks can cause serious and costly damage to buildings. Water seeping into attics and interior spaces leads to mold, rot, and deterioration. When it comes to protecting roofs, an ounce of prevention is truly worth a pound of cure. That’s where high temp ice and water shield comes in. This innovative roofing underlayment provides a waterproof barrier that seals out leaks even in extreme conditions.

We’ll also compare costs and help you decide if it’s right for your roofing needs.

What is High Temp Ice and Water Shield?

High temp ice and water shield is a type of roofing underlayment designed to withstand high temperatures up to 260degF. It protects against water penetration on metal roofs caused by ice dams, wind-driven rain, and pooling water.

Composition and Materials

This advanced shielding contains polymer modified asphalt blended with additives like styrene-butadiene-styrene. This boosts the asphalt’s elasticity and adhesion properties. It also typically includes a polyester fabric reinforcement layer for increased strength and durability.

Some versions also contain ceramic granules on the surface which reflect UV rays. This prevents degradation from sunlight. The components work together to create a flexible, bonded, watertight membrane.

high temp ice and water shield

Key Capabilities

Unlike standard ice and water barriers, high temp products withstand temperatures up to 260degF without deteriorating. This extreme heat resistance makes them ideal for metal roofs which get very hot.

The polymer modified asphalt also forms a fully adhered waterproof barrier. This blocks water from penetrating the roof deck and causing interior leaks and damage.

In addition, the membrane bonds firmly to the roof surface while maintaining flexibility. It can also seal tightly around fasteners and roof penetrations like vents and pipes.


Two of the leading brands of high temp ice and water shield are Grace Ice and Water Shield HT from GCP Applied Technologies and ALCO ShieldTM HT. Both offer the heat resistance, UV protection, and waterproofing durability needed for metal roofing applications.

How Does It Work?

Let’s look at how high temp ice and water shield is able to provide such robust leak protection, even in extreme conditions.


The polymer modified asphalt membrane bonds tenaciously to the roof surface while remaining flexible. This creates a fully adhered barrier that water cannot penetrate. The fabric reinforcement further strengthens the barrier against pooling water and high winds.

Standard shingle underlayments absorb water and allow it to seep through. High temp shield stops leaks in their tracks before they ever reach the roof deck.

High Heat Resistance

Unlike traditional ice and water barriers, high temp shield is designed to withstand scorching rooftop temperatures up to 260degF. The polymer modified asphalt and special additives prevent the product from deteriorating under such extreme heat.

On dark-colored metal roofs in hot climates, surface temperatures can exceed 165degF. Standard shields fail under those conditions while high temp products keep roofs safely sealed.


Proper installation is critical to get the full benefit. High temp shield is installed directly on the roof deck before attaching metal roofing. The sheets are overlapped 2-3 inches and sealed around any penetrations.

Fastener heads that secure the metal roofing must also be sealed over thoroughly. Adhering closely to the manufacturer’s instructions is essential for good performance.

Key Benefits

Let’s look at some of the top benefits that make high temp ice and water shield worth the investment:

Ice Dam Prevention

In cold climates, ice dams often form along the eaves and cause water to back up under shingles. This leads to leaks as water penetrates small cracks and openings.

High temp shield applied at vulnerable areas blocks moisture penetration and drainage from ice dams. This protects interiors from costly water damage.

Wind-Driven Rain Resistance

Wind-driven rain can be an insidious source of leaks. Gusting winds force water to infiltrate under shingles and through tiny gaps. High temp barrier’s bonded membrane prevents wind-blown rain from seeping through.

Leak Protection

By providing a fully adhered waterproof barrier, high temp shield keeps water out. It protects vulnerable areas like eaves, valleys, dormers and skylights. Water won’t penetrate openings around fasteners either.

Fewer leaks means less chance for mold, rot and interior damage. Attics and insulation stay dry too.


The rugged polyester reinforced material stands up well to foot traffic, UV rays, and extreme temperatures. It won’t crack or peel off like lower quality barriers.

High temp shield remains firmly bonded to the roof long-term. The waterproof barrier won’t degrade or allow leaks years down the road.

Metal Roof Compatibility

Metal roofs present some unique leakage risks with all the panel seams and fasteners. High temp shield is specifically designed for metal roofing. The unmatched heat resistance handles scorching metal roof temperatures.

It bonds tightly to metal panels without reacting or corroding them. The result is reliable leak protection that complements metal roofing’s sleek looks.

Cost Comparison

High temp ice and water shield costs more than standard versions. A 4′ x 50′ roll retails for $200-$250. Standard barrier costs about $100 for the same coverage.

The price premium pays off when you consider high temp shield’s superior performance and durability. Over the lifespan of a roof, it can save many times its added cost compared to repairs needed from leak damage.

By providing advanced protection from leaks on vulnerable metal roofs, high temp barrier delivers great value for the investment.

Preventing the extensive damage leaks cause makes high temp ice and water shield a worthwhile upgrade. It provides complete leak protection on metal roofs by sealing out water penetration.

The polymer modified asphalt and rugged construction allow it to handle scorching heat up to 260degF. This extreme temperature resistance keeps roofs safely sealed against leaks on hot metal panels.

While costing more upfront, high temp shield saves money in the long run by preventing costly leaks. For critical leak protection on metal roofs, this innovative product delivers essential, long-lasting performance.

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