Mastic Aluminum Outside Box Miter 5 in. or 6 in. .019 Gutter Corner
The Mastic Aluminum Outside Box Miter is a preformed corner section where two straight gutter runs meet at an outside corner, available in 5 in. and 6 in. sizes with a .019 aluminum gauge. The two gutter sections slide into the miter, and all seams are caulked so water travels around the corner without leaking. Sold per piece in a range of Mastic gutter colors.
Key Features:
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Sealed Corner Joints: Once the two gutter sections are slid into the miter, all seams are caulked so water cannot leak or drip through.
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Durable Aluminum Build: Formed from .019-gauge aluminum to match standard Mastic gutter coils.
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Preformed Convenience: Pre-mitered corner saves field cutting and seaming of straight gutter sections at outside corners.
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Two Gutter Sizes: Offered in both 5 in. and 6 in. gutter sizes to match the K-style gutter runs.
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Wide Color Selection: Available in 12 colors including Black, Classic Cream, Charcoal, Dark Bronze and Terra Bronze.
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Matched Gutter System: Designed to pair with Mastic aluminum gutter runs and accessories.
Specifications Table:
| Specification |
Details |
| Brand |
Mastic |
| Sell unit |
1 piece |
| Product line |
Mastic Gutter Systems |
| Available colors |
Black, Classic Cream, Evergreen, Harbor Gray, Victorian Gray, Charcoal, Linen, Terra Bronze, Dark Bronze, Everest, Montana Suede, Cameo, Charcoal Gray |
| Available sizes |
5" .019 and 6" .019 |
| Material |
Aluminum |
| Color / finish |
Multiple baked colors; choose to match gutter run |
| Dimensions |
Preformed outside corner box miter, 5 in. or 6 in. gutter profile |
| Thickness |
.019 in. |
| Pack quantity |
1 piece (some colors supplied in cartons) |
| Intended use |
Outside corner connection for two straight gutter runs |
| Assembly |
Slide gutter sections into miter, caulk all seams |
Coverage & How Much You Need:
One miter forms a single outside gutter corner. Count the outside corners on the gutter layout and order one miter per corner, matching the gutter size.
Fit and Compatibility:
Fits Mastic 5 in. and 6 in. aluminum K-style gutter runs; choose the miter size and color to match the adjacent gutters. Sealer/caulk and end caps or straight gutter are sold separately.
Frequently Asked Questions (FAQ):
Q: What is included with one order?
A: One preformed aluminum outside box miter in the selected size and color; straight gutter, caulk and hangers are ordered separately.
Q: How do I install this miter?
A: Slide the two straight gutter sections into the miter, then caulk all seams so water cannot leak or drip through.
Q: What size should I choose?
A: Match the miter size (5 in. or 6 in.) to the gutter profile it will join.
Q: Will it rust?
A: It is formed from aluminum, which is rust-resistant for exterior gutter service.
Q: How many do I need?
A: Order one miter for each outside corner where two straight gutter runs meet.
Q: What colors are available?
A: Thirteen colors are listed across the line, including Black, Classic Cream, Evergreen, Charcoal, Dark Bronze, Terra Bronze and Montana Suede, in 5 in. or 6 in. sizes.
Expert Verdict — Reviewed by the SuperArbor Pro Desk
Order miters in the same gauge (.019) and color as the gutter coil so the finished corner reads as one continuous run. Dry-fit both gutter ends into the miter before sealing, verify slope toward the outlet, then caulk every seam generously. For homes with many corners, preformed miters like these save significant field-seaming time versus hand-cutting straight stock.
Work from a stable ladder or lift when installing gutter miters, and follow caulk and sealant safety directions.
Order your Mastic Aluminum Outside Box Miter in the exact size and color to match your gutter run.
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