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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4.4 ★★★★★
Based on 5 reviews
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Product Reviews
I
Verified Purchase
Ivar Andreassen
Charlottesville, US
★★★★★ 5
Worked perfectly!
Size: 96158T-1PCS
Have an older Mercury 40hp 2 stroke. This Solenoid worked perfectly. It is not that easy to install, due to the design of the engine. It does require a bit of patient and the right tools to do it. If you have big hands and don't do this type of repair to often, call a friend that is better than you to get some help :) I have an older engine but it runs like charm. I will order an extra Solenoid and place in the box of "important spare parts" for the future. Very good experience for the purchase and overall quality of the part.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on January 14, 2022
M
Verified Purchase
me
Los Angeles, US
★★★★★ 5
Perfect fit and works great
Size: 96158T-2PCS
Perfect fit and works great. It is great that it comes as a 2pk. I replaced both with no need to change wiring, and kept the working one I had, as backup.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 27, 2026
T
Verified Purchase
Tom K.
Grantham, US
★★★★★ 4
It works as it should...
Size: 96158T-2PCS
Used it in a pinch for stater relay... it works great. Be aware... Mine required metric sockets for the nuts... 10mm for large terminals - 3/8 was too tight and same for smaller terminals 7mm fit better than 5/16 that was too loose. The mounting holes are also spaced closer together than the OEM on a mercruiser 260 in a mid 1980's boat but easy to remedy with a 1/4" drill bit.
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Reviewed in the United States on August 4, 2023
D
Verified Purchase
Don
Lowell, US
★★★★★ 5
Fixed 4.3 Merc IO
Size: 96158T-1PCS
Engine wouldn't start reliably or consistently. I had no clicking either from the old solenoid even though it would start from time to time...motor starts perfect after install. Pretty easy install as long as you reconnect the right wires. This worked perfect!
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Reviewed in the United States on August 8, 2023
M
Verified Purchase
Mr Sexy
Dallas, US
★★★★★ 5
Quality
Size: 96158T-2PCS
Worth the money. Quality. Fit good. Easy too install.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on September 21, 2025

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