Mastic Structure 1-1/4 in. x 10 ft. Inside Corner Post Vinyl Siding Trim
Mastic Structure Inside Corner Posts are 1-1/4 in. x 10 ft. vinyl siding trim pieces that finish inside corner transitions. This line is offered in 18 colors, from White and Desert Sand to Rugged Canyon and Everest, so it can match Structure siding panels. Each item is sold per piece unless otherwise noted, and pairs with Mastic Structure siding and matching outside corner posts.
Key Features:
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Inside corner finish: Designed to trim and conceal the inside corner transitions of Mastic Structure siding installations.
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10 ft. length: Each post is 10 ft. long, a standard siding trim length for efficient wall coverage.
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18 color choices: Available in 18 colors to coordinate with Mastic Structure siding panels.
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Structure system match: Part of the Mastic Structure accessories line for a coordinated siding system.
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Durable vinyl trim: Vinyl construction suited to exterior siding applications.
Specifications Table:
| Specification |
Details |
| Brand |
Mastic |
| Sell unit |
1 piece (some colors by carton) |
| Product line |
Mastic Structure |
| Available colors |
Desert Sand, White, Montana Suede, Pebblestone Clay, Silver Gray, Wicker, English Wedgewood, Quiet Willow, Rugged Canyon, Scottish Thistle, Victorian Gray, Classic Cream, Cameo, Harbor Gray, Autumn Harvest, Deep Granite, Everest, Linen |
| Available sizes |
1-1/4 in. x 10 ft. |
| Material |
Vinyl |
| Dimensions |
1-1/4 in. x 10 ft. |
| Intended use |
Inside corner trim for vinyl siding installations |
Coverage & How Much You Need:
Each 10 ft. post finishes one inside corner for one story of wall height; plan roughly one post per inside corner per 10 ft. of vertical run, lapping successive pieces per standard siding trim practice.
Fit and Compatibility:
Made to pair with Mastic Structure vinyl siding panels and matching Structure accessories such as outside corner posts and starter strips. Posts are trim components and are installed with the siding, which is sold separately.
Frequently Asked Questions (FAQ):
Q: What size is this inside corner post?
A: It measures 1-1/4 in. wide by 10 ft. long.
Q: What colors are available?
A: 18 colors including White, Desert Sand, Pebblestone Clay, Silver Gray, Rugged Canyon, Scottish Thistle, Harbor Gray, Deep Granite, Everest and Linen.
Q: How many do I need?
A: Plan one 10 ft. post per inside corner for each 10 ft. of vertical wall height, with pieces lapped as needed.
Q: What does it pair with?
A: Mastic Structure vinyl siding panels and other Structure accessories.
Q: How is it sold?
A: Each item in this line is sold as an individual piece or carton depending on the color variant.
Expert Verdict — Reviewed by the SuperArbor Pro Desk
Order inside and outside corner posts before the siding itself so wall layout can be set to the trim. Keep color consistent by ordering all trim for a job at the same time, as vinyl dye lots can vary between runs. Nail sparingly through the center of the nailing slot and leave room for thermal movement, which matters on 10 ft. lengths.
Use ladder and fall-protection precautions when installing trim above ground level, and follow local building codes for siding attachment.
Order Mastic Structure Inside Corner Posts to complete your Structure siding installation with a matched color.
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