SKU: 99275124334

GAF Silicone Mastic, White — 3.5 Gallon Pail

Sale price$94.13 Regular price$104.59
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Description

GAF Silicone Mastic, White — 3.5 Gallon PailGAF Silicone Mastic Sealant, White (3. 5 Gal) Professional grade, thick silicone mastic designed for flashing and detail work. Low odor, fast moisture cure formula adheres strongly to a wide range of roofing substrates. Key Features: High Build Silicone Sealant: Thick consistency for robust coverage on seams, penetrations, and flashing details Easy Application: Low odor and smooth tooling help speed installs on the jobsite Fast Moisture Cure: Cures

GAF Silicone Mastic Sealant, White (3.5 Gal)

Professional-grade, thick silicone mastic designed for flashing and detail work. Low-odor, fast moisture-cure formula adheres strongly to a wide range of roofing substrates.


Key Features:

  • High-Build Silicone Sealant: Thick consistency for robust coverage on seams, penetrations, and flashing details
  • Easy Application: Low odor and smooth tooling help speed installs on the jobsite
  • Fast Moisture Cure: Cures quickly to reduce downtime and return roofs to service faster
  • Strong Multi-Surface Adhesion: Formulated to bond to a variety of common roofing substrates
  • Tested Performance: Meets ASTM D1644, D2697, and D2370 standards

Specifications Table:

Specification Details
Color White
Package Size 3.5 Gallon Pail
Item Weight 42 lb
Standards ASTM D1644; ASTM D2697; ASTM D2370
Manufacturer Number 891402WH
Product Number GAFSM35WH
Category Adhesives, Caulks & Sealants
Description A thick, high-build silicone sealant featuring low odor, easy application, fast moisture cure, and enhanced adhesion to a variety of substrates.

Frequently Asked Questions (FAQ):

Q: What is the color of this silicone mastic?
A: White.


Q: How much product is in the container?
A: 3.5-gallon pail.


Q: What standards does it meet?
A: ASTM D1644, ASTM D2697, and ASTM D2370.


Q: Where is it typically used?
A: For flashing, seams, penetrations, and detail repairs on compatible roofing systems.


Q: Does it have strong odor?
A: No—it's a low-odor formula for easier application.


Sculpted Protection with a Clean, Architectural Finish

This silicone mastic draws a crisp, modern line around roof penetrations and edges, bringing order and polish to functional details. I love the dense, high-build body—it lays down with confidence and dries into a sleek, resilient skin. Use it to frame flashing and seams with a refined, white accent that feels intentional. It’s a quiet essential—performance-forward and luxuriously reliable.


Seal critical roof details with confidence—choose this GAF Silicone Mastic for fast-curing, durable adhesion that lasts.

Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 99275124334

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4.0 ★★★★★
Based on 6 reviews
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Verified Purchase
Tina C.
Pawtucket, US
★★★★★ 5
Queen Elisabeth
Absolutely love this brand. Thick and creamy and yet still does not feel greasy. It last all day long.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on October 14, 2025
N
Verified Purchase
Nee-C in SC
San Leandro, US
★★★★★ 5
Use it every day, absorbs q
Love this item, hard to o find in store, great price for 2 pkag, out on auto ship, use it every day.
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Reviewed in the United States on April 21, 2026
S
Verified Purchase
Svitlana
New York, US
★★★★★ 5
Simple, fragrance-free base lotion that plays well under sunscreen
Size: 18 Ounce (Pack of 1)
I bought this as a moisturizing base before beach days, on my dermatologist s-style routine: at home I apply this lotion first, let it sink in, then tanning cream, and then layer broad-spectrum sunscreen (SPF) on top. The goal was an even, soft, brown tan without that tight, dry feeling after sun and salt. In this role, it worked well for me. I didn’t finish the bottle over the season, and now I use it after the shower as my everyday body lotion. Why I chose it (and what actually “works” here): It’s fragrance-free and non-comedogenic, so it’s basic and gentle. The key active is colloidal oatmeal, a classic skin protectant that helps soothe and support the moisture barrier. Value for money was the clincher: a big bottle, simple formula, no extras I don’t need. Real-life notes from first use: It’s not ultra-rich (don’t expect a heavy occlusive butter), but as a daily hydrator or under-SPF base, it’s reliable and comfortable .The texture is fast-absorbing and non-greasy on my slightly dry skin. So, a straightforward, affordable oatmeal lotion that kept my skin calm under sunscreen in summer and now does the job after showers. No complaints—just a workhorse moisturizer that earns its keep.
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Reviewed in the United States on October 14, 2025
M
Verified Purchase
Mychailo Toloczko
West Palm Beach, US
★★★★★ 5
Great lotion, not smelly
Size: 18 Ounce (Pack of 6)
Our go-to moisturizing lotion. Great price, and the best lotion we've used. And not fragrant!
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Reviewed in the United States on March 4, 2026
M
Verified Purchase
marjie zimmerman
Birmingham, US
★★★★★ 5
Good basic lotion
Size: 18 Ounce (Pack of 1)
Moisturizes and is good quality but it has a terrible smell until drying and then it has no scent
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Reviewed in the United States on May 12, 2026

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