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The Malarkey 406 Secure Start HT High Temperature Underlayment is a ice & water underlayment for jobs that require Malarkey model/MPN 406SGT1 in the RL sell unit. 406 Secure Start HT is a self-adhering, high temperature underlayment suitable for use as a waterproof underlayment in steep slope roofing applications with metal roofing, asphalt shingles, wood shakes/shingles, and mechanically-fastened roof tile.

Key Specs

• Brand: Malarkey
• Model / MPN: 406SGT1
• SKU: MAL406USGT2
• Sell unit: RL
• Product type: Ice & Water Underlayment
• Size / color: 2 Square/Roll
• Category: Residential Roofing | Residential Roofing/Underlayment | Residential Roofing/Underlayment/Ice & Water Underlayment | Underlayment | Underlayment/Ice & Water Underlayment
• Coverage / unit: 2 squares (200 sq ft) per roll

Key Features

• Secure Start HT (high temperature) is a self-adhering underlayment with superior thermal stability and adhesion properties, making it the right choice for complete deck coverage under metal
• Malarkey offers two ice & water barriers tailored to asphalt shingle roofs. Secure Start HT was designed for metal roof applications but also delivers superior performance under asphalt shingles
• Given its superior performance, it is recommended in more extreme climates, areas with higher elevation, high winds, and wind-driven rain, and those more prone to ice damming.

Coverage & How Much You Need

This item is listed as 2 squares (200 sq ft) per roll. Use the project takeoff, manufacturer installation instructions, and expected waste/overlap to confirm the order quantity.

Compatibility / Fitment

Use this item only when the brand, model/MPN, size/color, sell unit, and system type match the project specification. Do not substitute it for a different ice & water underlayment, pack size, color, membrane/system family, or installation condition without checking the manufacturer instructions.

FAQs

What exactly am I ordering?

Malarkey 406 Secure Start HT High Temperature Underlayment, sold as RL, with SKU MAL406USGT2 and manufacturer model/MPN 406SGT1.

What model or part number should I match?

Match model/MPN 406SGT1 and confirm the brand is Malarkey. If the job spec lists a different model, size, color, or system family, hold for review.

What unit is the price based on?

This listing is built around the RL sell unit. Confirm the unit before comparing price, quantity, or coverage.

How do I estimate quantity?

Use 2 squares (200 sq ft) per roll, then add waste or overlap per the manufacturer instructions and the project design.

What should be checked before purchase?

Confirm the model/MPN, sell unit, size/color, jobsite condition, compatible system components, and any manufacturer installation limits before approving the order.

Roofing and exterior-envelope work can involve fall hazards, weather exposure, fumes, adhesives, and system-specific installation requirements; follow the manufacturer instructions, OSHA-safe work practices, and local code or use a qualified contractor.

Product Expert Notes

Choose this item when Malarkey model/MPN 406SGT1, SKU MAL406USGT2, and the RL sell unit match the project requirement. It is best treated as an exact-match material selection, not a generic substitute.