{"product_id":"hal-industries-felt-p40-astm-d4869-asphalt-underlayment-roll-4-squares-per-roll","title":"HAL Industries Felt P40 ASTM D4869 Asphalt Underlayment Roll, 4 Squares per Roll","description":"\u003ch1\u003eHAL Industries Felt P40 ASTM D4869 Asphalt Underlayment Roll, 4 Squares per Roll\u003c\/h1\u003e\u003chr\u003e\u003cp\u003e\u003cstrong\u003eHAL 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.\u003c\/strong\u003e\u003c\/p\u003e\u003chr\u003e\u003ch2\u003eKey Features:\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eASTM D4869 Rated:\u003c\/strong\u003e Manufactured to the ASTM D4869 specification for asphalt-saturated organic felt.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWaterproof and Breathable:\u003c\/strong\u003e Impervious to bulk water penetration but allows water vapor to pass at a restricted rate.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAlignment Guidelines:\u003c\/strong\u003e Guidelines every 2 in. across the sheet help keep asphalt shingles aligned.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePre-Conditioned:\u003c\/strong\u003e Pre-conditioned to lay flat and remain stable once installed on the deck.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDual-Stage Use:\u003c\/strong\u003e Installs as a temporary roof cover during construction and serves as permanent shingle underlayment afterward.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStorm Backup:\u003c\/strong\u003e Can act as temporary protection if shingle blow-off occurs.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWall Breather:\u003c\/strong\u003e Also suitable as a waterproof breather sheet on side-walls beneath the outer finish.\u003c\/li\u003e\n\u003c\/ul\u003e\u003chr\u003e\u003ch2\u003eSpecifications Table:\u003c\/h2\u003e\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003e\u003cstrong\u003eSpecification\u003c\/strong\u003e\u003c\/th\u003e\n\u003cth\u003e\u003cstrong\u003eDetails\u003c\/strong\u003e\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eBrand\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eHAL Industries\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eSell unit\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e1 roll, 4 squares\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eProduct line\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eHAL P40 Felt\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eAvailable sizes\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e4 squares per roll\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eMaterial\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eOrganic felt saturated with waterproofing asphalt\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eCoverage per unit\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e4 squares (400 sq ft nominal per roll)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eIntended use\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eAll-purpose protective waterproof sheet; temporary roof cover; permanent shingle underlayment; side-wall breather sheet\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003chr\u003e\u003ch2\u003eCoverage \u0026amp; How Much You Need:\u003c\/h2\u003e\u003cp\u003eEach 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.\u003c\/p\u003e\u003ch2\u003eFit and Compatibility:\u003c\/h2\u003e\u003cp\u003eWorks 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.\u003c\/p\u003e\u003chr\u003e\u003ch2\u003eFrequently Asked Questions (FAQ):\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003eQ: How much does one roll cover?\u003c\/strong\u003e\u003cbr\u003e\u003cstrong\u003eA:\u003c\/strong\u003e One roll covers 4 squares, or about 400 square feet nominal before laps.\u003c\/p\u003e\u003chr\u003e\u003cp\u003e\u003cstrong\u003eQ: Can it be left exposed during construction?\u003c\/strong\u003e\u003cbr\u003e\u003cstrong\u003eA:\u003c\/strong\u003e Yes, it is designed to serve as a temporary roof cover during house construction, then remain as permanent underlayment under the finished shingles.\u003c\/p\u003e\u003chr\u003e\u003cp\u003e\u003cstrong\u003eQ: Does it work under siding?\u003c\/strong\u003e\u003cbr\u003e\u003cstrong\u003eA:\u003c\/strong\u003e Yes, it can be used as a waterproof breather sheet on side-walls beneath the outer finish.\u003c\/p\u003e\u003chr\u003e\u003cp\u003e\u003cstrong\u003eQ: Are there alignment guides on the felt?\u003c\/strong\u003e\u003cbr\u003e\u003cstrong\u003eA:\u003c\/strong\u003e Yes, guidelines are provided every 2 inches across the sheet to help keep shingle courses aligned.\u003c\/p\u003e\u003chr\u003e\u003cp\u003e\u003cstrong\u003eQ: What happens if shingles blow off?\u003c\/strong\u003e\u003cbr\u003e\u003cstrong\u003eA:\u003c\/strong\u003e The P40 felt can act as temporary protection over the deck if shingle blow-off occurs until repairs are made.\u003c\/p\u003e\u003chr\u003e\u003ch2\u003eExpert Verdict — Reviewed by the SuperArbor Pro Desk\u003c\/h2\u003e\u003cp\u003eP40 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.\u003c\/p\u003e\u003cp\u003e\u003cem\u003eAsphalt 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.\u003c\/em\u003e\u003c\/p\u003e\u003chr\u003e\u003cp\u003e\u003cstrong\u003eOrder HAL Industries Felt P40 ASTM D4869 rolls for dependable underlayment on your next shingle project.\u003c\/strong\u003e\u003c\/p\u003e","brand":"HAL Industries","offers":[{"title":"Default Title","offer_id":53524639351151,"sku":"HALFE2025","price":42.25,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0830\/3499\/7051\/files\/ProductImage_Hal_HALFE1000_3e70086d-3690-4cf0-9028-e001e25852f8.jpg?v=1790284757","url":"https:\/\/superarbor.io\/products\/hal-industries-felt-p40-astm-d4869-asphalt-underlayment-roll-4-squares-per-roll","provider":"Super Arbor","version":"1.0","type":"link"}