GAF Silicone Mastic, White — 3.5 Gallon Pail
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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4.1 ★★★★★
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Love2Cook
Battle Creek, US
★★★★★ 5
Treasured chew toy
Flavor Name: Marshmallow & Peanut Butter, Size: Large
I'm on my 2nd one of these as my dog is obsessed with it! He's a heavy chewers and the 1st one lasted 1 month. Held up pretty well for his strong jaws and he loves it. Great buy!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on October 30, 2025
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Verified Purchase
Natures Retreat
Birmingham, US
★★★★★ 3
Dog likes it
Flavor Name: Marshmallow & Peanut Butter, Size: Large
It wears faster on the longer side, my dog does love this, but 2 sides are not chewed as much.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on October 19, 2025
S
Verified Purchase
slz
New York, US
★★★★★ 5
Terrific! Much easier to use than Kongs and my dog loves it.
Flavor Name: Peanut Butter, Size: Medium
I like these so much better than the original Kongs. The large opening makes it so much easier to put peanut butter or cream cheese into it. Plus much easier to clean out afterwards. My dog also likes to chew it and play with it throwing it in the air after he’s done eating the peanut butter. Very sturdy - he chews apart stuffed toys but his chewing hasn’t damaged this at all. I highly recommend this product!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on October 9, 2025
T
Verified Purchase
T Wolf
Phoenix, US
★★★★★ 5
Great for strong chewing dogs. Entertaining too!
Flavor Name: Peanut Butter, Size: Medium
My black lab can destroy the toughest of dog chew toys, but he's not destroyed this peanut. I fill it with peanut butter, yogurt, pumpkin or apple sauce and freeze it. It keeps him entertained for quite a while. When the filling is gone, he leaves it alone or carries it around begging for a filled one.
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Reviewed in the United States on March 31, 2026
H
Verified Purchase
Heather Murphy
Pawtucket, US
★★★★★ 5
Super cute! If you have one dog it'll last a while. If you have more than one...buy two.
Flavor Name: Marshmallow & Peanut Butter, Size: Large
This is THE FAVORITE chew toy in our household. We have two grown labs and a 10 month old mutt and they all love this toy. They got a variety of chew toys at Christmas and this is the one that they steal from each other. That said, they've definitely managed to kill it. It's well worth the money and it's held up well to heavy chewers but four months later and we're going to have to buy a new one. It's now a stub. They managed to break off all the marshmallows about a week ago and the stick itself is more like a chunk now but we definitely got our money's worth.
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Reviewed in the United States on May 1, 2025

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