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Professional Service
Sealants, Tapes & Mastics
Professional Grade Solutions for Air-Tight Compliance
A high-performance duct system is only as good as its seal. Diaz Sheet Metal stocks a curated selection of UL-181 listed mastics, industrial-strength tapes, and high-temperature sealants designed to ensure your installation meets the most rigorous pressure testing and code requirements.
Our Services
UL-181 Fiber Mastics
Fiber-reinforced, water-based sealants designed for high-velocity and high-pressure duct systems (up to 15" w.g.).
Industrial Adhesion
Professional-grade FSK and butyl tapes providing long-term air-tight performance in both indoor and outdoor climates.
Hi-Temp RTV Silicone
NSF-rated high-temperature silicone sealants engineered for liquid-tight grease duct seams and industrial exhaust.
Firestopping Systems
Intumescent sealants and fire-caulk for code-compliant fire-rating restoration at wall and floor penetrations.
Why Choose Diaz Sheet Metal?
Low-VOC and LEED-compliant options for green building projects
Exceptional flexibility to withstand system vibration and expansion
Mold and mildew resistant formulations for high-moisture areas
Superior UV resistance for outdoor roof-top duct installations
Available in buckets, tubes, and bulk cases for contractor efficiency
Tested for compatibility with all Galvanized, Stainless, and Aluminum duct
Our Process
1
Application Audit
We help you select the sealant based on system pressure class (Low, Med, or High).
2
Surface Preparation
Expert advice on cleaning surfaces to ensure maximum bonding and seal longevity.
3
Proper Staging
We provide the right quantity of product to match your linear footage and joint count.
4
Pressure Testing
Our professional-grade products ensure you pass the duct-blaster and leakage tests.
Frequently Asked Questions
What is the importance of UL-181 rating?▼
The UL-181 rating ensures the sealant has been tested for fire safety, mold resistance, and long-term durability under pressure. Using non-rated sealants can lead to inspection failure and premature system leakage.
Should I use water-based or solvent-based mastic?▼
Water-based mastics are the industry standard for most indoor HVAC applications due to low odors and easy cleanup. Solvent-based mastics are often preferred for outdoor rooftop applications where moisture resistance during curing is critical.
How much mastic do I need per joint?▼
As a general rule, one gallon of mastic covers approximately 100 linear feet of joint at 1/16" thickness. We can help you calculate exact quantities based on your duct sizing and joint count.
Can these sealants be used on grease duct?▼
For grease ducts, standard mastics are prohibited. You must use high-temperature, liquid-tight RTV silicone that meets NSF and NFPA 96 requirements for kitchen exhaust systems.
Ready to Get Started?
Contact us today for a free estimate on your sealants, tapes & mastics project.