Understanding The Difference Between T-1 And T-2 Termination Bars
When it comes to through-wall flashing systems, proper termination is critical to keeping water out of the wall assembly. Termination bars—often referred to as “term bar”—play a key role in securing flashing membranes to the backup wall and maintaining a watertight seal.
Two of the most common styles used in masonry construction are the T-1 termination bar and the T-2 termination bar with lip. While both serve a similar purpose, their design differences can impact installation, sealant placement, and overall performance. Here’s what contractors need to know when choosing between the two.
WHAT IS A TERMINATION BAR?
A termination bar is a narrow strip—typically made from stainless steel, aluminum, or plastic—used to mechanically fasten flashing materials to a vertical substrate. It ensures the flashing remains securely in place and resists pullout from wind, moisture, and gravity loads.
After the bar is fastened, a bead of sealant is applied along the top edge to complete the waterproof seal. This simple step provides long-term protection against moisture intrusion at the top edge of the flashing.
T-1 TERMINATION BAR
T-1 is the most common and basic type of termination bar used in masonry applications. It has a flat profile, with pre-drilled holes for fasteners spaced evenly along the length.
Key features:
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Flat, straight edge design
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Typically 1/8" thick
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Pre-punched holes for fast installation
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Used to mechanically attach flashing to the wall before applying sealant
Common uses:
T-1 bars are ideal for standard through-wall flashing terminations where the wall surface is smooth and a separate bead of sealant can be applied cleanly along the top edge.
Advantages:
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Economical and easy to install
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Works well with a wide range of flashing materials (metal, rubberized asphalt, peel-and-stick membranes, etc.)
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Provides a solid mechanical attachment
Things to keep in mind:
Because the top edge is flat, the sealant must be applied neatly and continuously to create a proper seal. Inconsistent sealant application can allow moisture to enter behind the flashing over time.
T-2 TERMINATION BAR (WITH LIP)
The T-2 termination bar includes an additional drip lip or sealant lip along the top edge. This lip acts as a small ledge to hold and protect the sealant bead, providing an extra layer of defense against water intrusion.
Key features:
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Formed lip along the top edge to capture sealant
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Pre-punched holes for fasteners
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Designed for improved sealant adhesion and long-term waterproofing performance
Common uses:
T-2 bars are preferred in high-moisture or exposed environments, such as parapet walls, foundation transitions, and areas where water is more likely to collect or run down the wall face.
Advantages:
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Lip holds sealant in place, creating a more reliable waterproof termination
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Adds protection against UV exposure and washout of sealant
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Reduces maintenance concerns over time
Things to keep in mind:
Ensure the bar length and lip (for T-2) align with the sealant profile you plan to use so the sealant fully engages the termination.
INSTALLATION CONSIDERATIONS
Regardless of type, correct installation is essential for termination bars to perform properly. Contractors should:
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Ensure the flashing is clean, dry, and firmly attached before fastening the bar.
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Use appropriate fasteners for the substrate (masonry, concrete, or wood).
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Apply continuous pressure to the bar while fastening to prevent gaps.
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Seal along the top edge of the bar—especially at fastener penetrations.
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Avoid overdriving screws, which can deform the bar or damage the flashing.
If using a T-2 bar, be sure the sealant fully fills the lip and extends slightly above it to ensure complete coverage.
HELPFUL TIPS
When installing either T-1 or T-2 termination bars, keeping a few key considerations in mind can improve performance and longevity:
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Material compatibility: Make sure the termination bar material (stainless steel, aluminum, or galvanized) is compatible with your flashing membrane to avoid galvanic corrosion.
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Fastener selection: Confirm the correct type and spacing of fasteners for your substrate — masonry, concrete, and wood all require different anchors.
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Sealant and joint considerations: Pay attention to UV exposure and movement joints; choose a sealant rated for exterior conditions and the expected expansion or contraction of the wall.
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Fastener penetration: Inspect and seal all screw or anchor penetrations carefully, as even small gaps can allow water intrusion.
By following these tips, contractors can ensure both T-1 and T-2 termination bars perform as intended, protecting the wall assembly and maintaining a reliable drainage path.
FINAL THOUGHTS
Termination bars may be a small component of the wall system, but they play an outsized role in keeping water out. Understanding the difference between T-1 and T-2 termination bars helps contractors make the right call for each project—balancing cost, performance, and longevity.
At Masonry Direct, we supply a full range of termination bars and moisture management products designed to help contractors build better, longer-lasting walls. Whether you’re working on a new commercial project or a repair, our team is here to help you find the right solution for your job.