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Malarkey Right Start UDL SBS Modified Fiberglass Mat Roofing Underlayment Roll, 39-3/8 in. x 66 ft.
Regular price $127.60Orders start at $399 — combine any items to reach the minimum. Learn more
Malarkey Right Start UDL SBS Modified Fiberglass Mat Roofing Underlayment Roll, 39-3/8 in. x 66 ft.
Malarkey Right Start UDL is an SBS modified asphalt roofing underlayment on an inorganic fiberglass mat, sand coated, supplied as a roll measuring 39-3/8 in. x 66 ft. Each roll weighs a minimum of 70 lb. Install one layer mechanically fastened to the sheathing under Class A asphalt shingles.
Key Features:
- SBS modified asphalt: Inorganic fiberglass mat saturated with SBS modified asphalt for flexible, durable performance.
- Sand coated: Surface is coated with sand for handling and installation.
- Class A rated: Tested to UL 790 and ASTM E108 as part of a Class A combustible deck assembly at 5:12 slope.
- Large roll: Rolls are 39-3/8 in. (1000 mm) wide and 66 ft. (20.12 m) long for fast coverage.
- Florida approved: Holds Florida Product Approval FL No. 14807 (non-HVHZ) and FL No. 15214 (HVHZ).
Specifications Table:
| Specification | Details |
|---|---|
| Brand | Malarkey |
| Manufacturer model | UDL |
| Sell unit | 1 roll, 39-3/8 in. x 66 ft. |
| Material | Inorganic fiberglass mat saturated with SBS modified asphalt, sand coated |
| Nominal size | 39-3/8 in. x 66 ft. roll |
| Length | 66 ft. (20.12 m) |
| Width | 39-3/8 in. (1000 mm) |
| Intended use | Steep-slope roofing underlayment under asphalt shingles |
| Fire rating | Class A as part of listed assembly (UL 790 / ASTM E108) |
| Minimum roll weight | 70 lb (31.8 kg) |
| Approvals | Florida Product Approval FL No. 14807 (non-HVHZ), FL No. 15214 (HVHZ) |
Coverage & How Much You Need:
Each 39-3/8 in. x 66 ft. roll provides roughly 216 sq. ft. of raw material. Estimate roof area in squares and add allowance for side and end laps per the manufacturer's installation instructions.
Fit and Compatibility:
Designed as the underlayment layer in Malarkey steep-slope residential roofing systems beneath Malarkey asphalt shingles. In the Class A listing, it is installed with one layer mechanically fastened to 3/8-in. plywood sheathing with Class A shingles fastened over it.
Frequently Asked Questions (FAQ):
Q: What is included in the sell unit?
A: One roll of Malarkey Right Start UDL underlayment, 39-3/8 in. wide and 66 ft. long, weighing a minimum of 70 lb.
Q: How much area does one roll cover?
A: The roll is about 216 sq. ft. of material before lap allowances; plan coverage based on the manufacturer's required overlaps.
Q: How is it installed?
A: In the Class A listing, one layer is mechanically fastened to 3/8-in. plywood sheathing, with Class A asphalt shingles mechanically fastened over it at a 5:12 slope.
Q: Is it fire rated?
A: Yes, it is listed to UL 790 (2004) and ASTM E108 (2007) for Class A fire rating as part of the described combustible deck assembly.
Q: Does it have Florida Product Approval?
A: Yes, Malarkey roof underlayments carry FL No. 14807 for non-HVHZ and FL No. 15214 for HVHZ.
Expert Verdict — Reviewed by the SuperArbor Pro Desk
Right Start UDL is a good upgrade over organic felt because the SBS modified asphalt and fiberglass mat give it better flexibility and tear resistance on the deck. Roll it out horizontally from the eave up, keeping laps shingle-style so water sheds downward. Match the fastening pattern in the manufacturer's instructions to preserve the Class A listing, and order rolls based on roof squares plus lap waste.
Use fall protection and appropriate footwear when installing underlayment on sloped roofs, as modified asphalt surfaces can be slippery, especially when hot or damp.
Order Malarkey Right Start UDL underlayment rolls today and start your roof with a listed Class A base layer.
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