The best ice and water roof underlayment depends on your roof covering, expected heat, and how long the membrane may be exposed before the roofing goes on. These self-adhering products are designed to help protect roof decks from water intrusion, including water that can back up under shingles during ice dams. Compare the temperature limits, coverage, surface, and installation details below, then check that your choice meets local code and the roofing manufacturer’s requirements.
Table of Contents
Quick Comparison
| Product | Coverage | Notable Features | Best Fit |
|---|---|---|---|
| HydroShield Self Adhering Ice and Water Shield HT | 195 sq. ft. | High-temperature resistant; 120-day UV exposure limit | Metal roofs and hot roof surfaces |
| FT Synthetics Platinum HT-B | 200 sq. ft. | 100% butyl; 180-day UV resistance | High-heat and low-slope applications |
| HydroShield Self Adhering Ice and Water Shield | 100 or 195 sq. ft., depending on roll | Sand-based grip surface; listed for slopes of 2:12 or greater | Shingle roofs |
| Grace Self Adhering Ice and Water Shield | Check package details | Split release liner; reroofable design | A range of common roof coverings |
| POLYGUARD Deckguard HT | 225 sq. ft. | 40-mil membrane; stated heat resistance up to 260°F | Sloped decks and traditional roof coverings |
Our Picks: Best Ice And Water Roof Underlayment reviews
HydroShield HT: A High-Temperature Option for Metal Roofing
HydroShield HT is a self-adhering membrane with a blue polyolefin surface. The product is designed to resist heat and is listed for use beneath metal roofs, including copper and zinc. Its stated service-temperature range is -40°F to 250°F, which makes heat compatibility an important reason to consider it.
The 36-inch-wide, 65-foot roll covers 195 square feet. A split-back release liner is intended to make handling and application more efficient, while the skid-resistant surface can help with footing during installation. The product description also says it self-seals around nails and fasteners and has a selvage edge for waterproofing at laps.
This is a focused choice for a project where a high-temperature membrane is needed, especially under compatible metal roofing. Its stated UV exposure limit is 120 days, but that is not a substitute for following the roofing system’s installation schedule. The listed specifications include ASTM D1970, ICC listing, and UL classification; confirm the applicable requirements for your project before buying.
Pros:
- Designed for high-temperature applications and compatible metal roofs
- 195 square feet of coverage per roll
- Split-back liner and skid-resistant surface
- Self-sealing around nails and fasteners, according to the product description
Cons:
- Its stated UV exposure limit is shorter than the FT Synthetics option
- Confirm compatibility with your exact roof assembly and metal roofing system
Verdict: Choose HydroShield HT when high-temperature performance and use beneath compatible metal roofing are priorities.
FT Synthetics Platinum HT-B: Butyl Adhesive with Extended UV Resistance
Platinum HT-B is a 41-mil self-adhering underlayment made with 100% butyl, according to the supplied product details. The butyl layer is intended to bond to plywood or OSB roof decks. The roll measures 36 inches by 67 feet and covers 200 square feet.
Its 180-day UV resistance is the longest stated exposure limit among these five options. The product is also described as nail-sealable and as providing watertight laps. It is compatible with low-slope roofing materials such as EPDM and TPO, though you should confirm that the product fits the complete roof system rather than relying on material compatibility alone.
This product stands out for projects where a butyl membrane, longer stated UV exposure window, or compatibility with certain low-slope materials matters. It has a stated shelf life of 18 months or more, so check the product information and storage conditions when planning a project. Its roll coverage is close to the other full-size options, but it is slightly less than POLYGUARD’s listed 225 square feet.
Pros:
- 100% butyl construction
- 180-day stated UV resistance
- Listed for use with EPDM and TPO low-slope roofing materials
- 200 square feet of coverage per roll
Cons:
- Check compatibility with the full roof assembly and installation instructions
- Coverage is less than the POLYGUARD roll listed here
Verdict: Platinum HT-B is a strong candidate when you want a butyl-based membrane and a comparatively long stated UV exposure window.
HydroShield Standard: A Grip-Focused Membrane for Shingle Roofs
This HydroShield membrane has a sand-based surface intended to provide foot grip during installation. It is described for use under shingles and for roof slopes of 2:12 or greater. The product also self-seals around nails and fasteners, and its split-back liner is intended to make application easier to manage.
The product description lists two roll lengths: 33 feet with 100 square feet of coverage, or 65 feet with 195 square feet. Since the title identifies a single-roll, one-square product while the description includes both sizes, verify the selected roll length and coverage before ordering. The stated service-temperature range is -40°F to 200°F, and the UV exposure limit is 60 days.
This option has a broad set of listed certifications and approvals, including ASTM D1970, ICC-ESR-1930, and Class A fire resistance under ASTM E108 / UL 790. It is also listed as approved by the Florida Building Code, Miami-Dade County, and TDI. Those credentials can be useful when checking project requirements, but they do not replace verifying local code acceptance or the specific product configuration.
Pros:
- Sand-based surface is designed for added foot grip
- Two listed coverage sizes, depending on roll length
- Self-seals around nails and fasteners
- Multiple listed certifications and approvals
Cons:
- Listed UV exposure limit is 60 days
- Confirm the roll size, since the title and description refer to different coverage amounts
Verdict: Consider this HydroShield membrane for a shingle roof when the slope, temperature range, and selected roll size match your project.
Grace Self-Adhering Shield: Versatile Coverage for Common Roof Types
Grace Self-Adhering Ice and Water Shield is described as suitable beneath asphalt shingles, mechanically attached tiles, and most standing-seam metal roofs. Its 25-mil membrane is designed to create a watertight seal and adhere to the roof deck. The product also has a slip-resistant surface.
The ripcord split-release liner lets installers remove the backing as needed while positioning the membrane. The product is described as reroofable, meaning it will not attach to the underside of the exposed roof covering. It is also covered by CertainTeed’s SureStart Warranty, according to the product information.
The listing title specifies a 36-inch by 75-foot roll and mentions 35 rolls, but the supplied details do not clearly state the package coverage. Confirm whether the listing is for one roll or a multi-roll quantity before ordering. The product description does not provide a UV exposure limit or service-temperature range, so check the manufacturer’s current installation information if those limits matter to your job.
Pros:
- Listed for use under several common roof-covering types
- Ripcord split-release liner supports controlled installation
- Slip-resistant surface
- Described as reroofable and covered by a SureStart Warranty
Cons:
- Package quantity and total coverage need confirmation
- Supplied details do not state UV or service-temperature limits
Verdict: Grace is worth considering for a mixed-roofing project, but confirm the package quantity and installation limits before purchase.
POLYGUARD Deckguard HT: High Heat Rating and Generous Roll Coverage
POLYGUARD Deckguard HT is a 40-mil self-adhering membrane with a high-strength, slip-resistant backing and an asphalt compound. The product is made for sloped roof decks and is described as suitable under most traditional roof coverings, including shingles. Its stated heat resistance is up to 260°F.
The 3-foot-by-75-foot roll covers 225 square feet, the largest stated coverage in this group. A film release is designed to make application easier, and the membrane is described as self-sealing around nails to resist leakage from water backing up during ice dams or rain. The stated UV exposure limit is 60 days.
POLYGUARD lists puncture resistance of 22 lbf under ASTM E154. That specification may help when comparing membranes for a project, but it should be considered alongside the installation conditions and the product’s other requirements. Its stated heat limit is higher than the limits listed for the other products here, though roof-system compatibility still needs to be checked.
Pros:
- 225 square feet of coverage per roll
- Stated heat resistance up to 260°F
- Slip-resistant backing and film release for application
- Listed puncture-resistance specification and self-sealing design
Cons:
- Stated UV exposure limit is 60 days
- Confirm that its asphalt compound is suitable for your roof-covering system
Verdict: Choose Deckguard HT when you want a high-temperature membrane with substantial stated roll coverage for a compatible sloped roof.
How to Choose Ice and Water Roof Underlayment
Match the membrane to your roof covering
Start with the roofing material going over the underlayment. Some products are specifically described for shingles, while others list compatibility with metal roofing or low-slope materials such as EPDM and TPO. Check the underlayment instructions and the roof-covering manufacturer’s requirements together. A membrane that fits one part of the assembly may not be suitable for the full roof system.
Check the slope and installation area
Roof slope can affect which underlayment is appropriate. HydroShield’s standard membrane is listed for slopes of 2:12 or greater, while the Deckguard HT description specifies sloped roof decks. Review the product instructions and local requirements for the exact areas you plan to cover, such as eaves, valleys, or other vulnerable sections. Do not assume every membrane is approved for every roof slope.
Compare heat limits and exposure time
Heat limits matter under roofing that can reach high temperatures, including some metal roof assemblies. Compare the stated service or heat-resistance range with the requirements for your roof. Also note the UV exposure limit: the products here list limits ranging from 60 to 180 days, while Grace’s supplied details do not state one. Plan installation so the membrane is covered within the applicable limit.
Measure coverage and confirm package size
Calculate the area you need to cover, then compare it with the roll’s listed coverage. The products in this group list coverage from 100 to 225 square feet per roll, but the Grace listing and one HydroShield listing have package or size details that should be confirmed before ordering. Allow for the layout and overlap required by the installation instructions rather than planning from roof area alone.
Consider the surface and release liner
Surface texture and liner design can affect how the membrane is handled. A sand-based or slip-resistant surface is intended to support footing, while split-back or ripcord liners can help with positioning and application. These features do not remove the need for safe roof access and proper installation practices.
Verify standards and local requirements
Look for the standards and approvals required for your project, then confirm that they apply to the exact product and intended use. The supplied descriptions list standards such as ASTM D1970 and ASTM E154, along with several regional approvals for some products. When in doubt, check the current product documentation and local building requirements before installation.
Frequently Asked Questions
What does ice and water roof underlayment do?
It is a self-adhering membrane installed on a roof deck to help limit water intrusion. These products are intended to protect vulnerable areas where water may back up under the roof covering, such as during ice dams or rain. It is one part of a roof assembly, not a replacement for the roof covering.
Can ice and water shield go under a metal roof?
Some products are listed for metal roofing. HydroShield HT is described as suitable under metal roofs such as copper and zinc, and Grace lists most standing-seam metal roofs. Always confirm compatibility with the specific metal roofing system and its installation instructions.
How long can the membrane remain exposed before roofing is installed?
It depends on the product. The supplied descriptions state UV exposure limits of 60 days for two options, 120 days for HydroShield HT, and 180 days for FT Synthetics Platinum HT-B. The Grace details provided here do not state a limit. Follow the product instructions and cover the membrane within its stated exposure window.
Can I use one of these products on a low-slope roof?
Check the exact product and roof assembly. FT Synthetics Platinum HT-B is described as compatible with low-slope materials such as EPDM and TPO. HydroShield’s standard product is listed for roof slopes of 2:12 or greater. Confirm the slope requirements in the installation instructions and local code.
How much underlayment should I buy?
Use the roof area that needs coverage and compare it with each roll’s stated coverage. Also account for the installation layout and required overlaps. Confirm package quantity before ordering, especially when the product listing describes more than one roll size or a multi-roll package.
Which option is best for a high-heat roof?
HydroShield HT is listed with a service-temperature range up to 250°F, FT Synthetics Platinum HT-B is identified as a high-temperature product, and POLYGUARD Deckguard HT states heat resistance up to 260°F. Compare the product documentation with the expected roof conditions and the covering manufacturer’s requirements before choosing.
Final Recommendation
For a high-temperature application beneath compatible metal roofing, HydroShield HT is the most directly targeted option. FT Synthetics Platinum HT-B is a compelling alternative when butyl construction and a longer stated UV exposure window are priorities. For broader comparison, POLYGUARD offers the greatest stated roll coverage, while the standard HydroShield model is specifically described for shingle roofs. Match the membrane to your roof system, confirm the package details, and follow the manufacturer’s installation instructions before you buy.
