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HAL Industries Felt P40 ASTM D4869 Asphalt Underlayment Roll, 4 Squares per Roll
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HAL Industries Felt P40 ASTM D4869 Asphalt Underlayment Roll, 4 Squares per Roll
HAL Industries Felt P40 is an ASTM D4869 asphalt-saturated organic felt underlayment supplied in a 4-square roll. It is strong, flexible, and impervious to water penetration while allowing water vapor to pass through at a restricted rate. It works as a temporary roof cover during construction and then remains as a permanent shingle underlayment.
Key Features:
- ASTM D4869 Rated: Manufactured to the ASTM D4869 specification for asphalt-saturated organic felt.
- Waterproof and Breathable: Impervious to bulk water penetration but allows water vapor to pass at a restricted rate.
- Alignment Guidelines: Guidelines every 2 in. across the sheet help keep asphalt shingles aligned.
- Pre-Conditioned: Pre-conditioned to lay flat and remain stable once installed on the deck.
- Dual-Stage Use: Installs as a temporary roof cover during construction and serves as permanent shingle underlayment afterward.
- Storm Backup: Can act as temporary protection if shingle blow-off occurs.
- Wall Breather: Also suitable as a waterproof breather sheet on side-walls beneath the outer finish.
Specifications Table:
| Specification | Details |
|---|---|
| Brand | HAL Industries |
| Sell unit | 1 roll, 4 squares |
| Product line | HAL P40 Felt |
| Available sizes | 4 squares per roll |
| Material | Organic felt saturated with waterproofing asphalt |
| Coverage per unit | 4 squares (400 sq ft nominal per roll) |
| Intended use | All-purpose protective waterproof sheet; temporary roof cover; permanent shingle underlayment; side-wall breather sheet |
Coverage & How Much You Need:
Each roll covers approximately 400 square feet (4 squares) nominal. Account for horizontal laps per local code when calculating actual coverage; a typical 3-4 inch head lap reduces the effective net area per roll.
Fit and Compatibility:
Works under asphalt shingles as a permanent underlayment and as temporary protection during construction. It can also be used as a waterproof breather sheet on side-walls under exterior finishes. It is not designed as the primary water barrier for low-slope or membrane roofs.
Frequently Asked Questions (FAQ):
Q: How much does one roll cover?
A: One roll covers 4 squares, or about 400 square feet nominal before laps.
Q: Can it be left exposed during construction?
A: Yes, it is designed to serve as a temporary roof cover during house construction, then remain as permanent underlayment under the finished shingles.
Q: Does it work under siding?
A: Yes, it can be used as a waterproof breather sheet on side-walls beneath the outer finish.
Q: Are there alignment guides on the felt?
A: Yes, guidelines are provided every 2 inches across the sheet to help keep shingle courses aligned.
Q: What happens if shingles blow off?
A: The P40 felt can act as temporary protection over the deck if shingle blow-off occurs until repairs are made.
Expert Verdict — Reviewed by the SuperArbor Pro Desk
P40 felt bridges the gap between lightweight No. 15 felt and heavier 30# felt; it is a solid all-purpose choice for steep-slope asphalt shingle roofs where a temporary cover is needed during framing. Use it where weather exposure between framing and shingling is expected. Its breather quality helps prevent deck rot compared with fully impermeable synthetic underlayments in some applications.
Asphalt felt is slippery when wet or on slopes; use fall protection and slip-resistant footwear during installation, and do not leave felt exposed to UV longer than the manufacturer allows.
Order HAL Industries Felt P40 ASTM D4869 rolls for dependable underlayment on your next shingle project.
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