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Mastic Corner Starter & Insert, White, 1/4 in. x 20 ft.
Regular price $49.12Orders start at $399 — combine any items to reach the minimum. Learn more
Mastic Corner Starter & Insert, White, 1/4 in. x 20 ft.
The Mastic Corner Starter & Insert in White is a 1/4 in. x 20 ft. siding accessory that provides a starting and receiving edge for corner trim installations. Sold as a single piece. It pairs with Mastic vinyl siding and corner trim components on exterior wall projects.
Key Features:
- Corner application: Serves as a starter and insert for siding corner installations.
- 20 ft. length: Long 20 ft. piece minimizes joints on typical wall corners.
- 1/4 in. profile: Slim 1/4 in. profile suits lineal corner assemblies.
- White finish: White finish coordinates with common siding and trim colors.
- Single piece: Sold per piece for easy job-sized ordering.
Specifications Table:
| Specification | Details |
|---|---|
| Brand | Mastic |
| Sell unit | 1 piece, 1/4 in. x 20 ft. |
| Product line | Mastic Lineals |
| Available colors | White |
| Available sizes | 1/4 in. x 20 ft. |
| Dimensions | 1/4 in. x 20 ft. |
| Intended use | Corner starter and insert for siding corner trim |
Coverage & How Much You Need:
Each 20 ft. piece covers one standard wall corner run up to 20 linear feet; order one piece per corner, or two for taller two-story runs, allowing for cuts.
Fit and Compatibility:
Intended for use with Mastic siding and corner trim assemblies; pairing with corresponding Mastic lineal corner components, sold separately, is recommended.
Frequently Asked Questions (FAQ):
Q: What is included?
A: One White 1/4 in. x 20 ft. corner starter and insert piece.
Q: How many pieces per corner?
A: One 20 ft. piece covers most single-story corner runs; taller walls may require a second piece with a joint.
Q: How is it installed?
A: Fasten it plumb at the corner, then install the mating trim or insert over it per the siding installation instructions.
Q: Is it available in other colors?
A: This page lists the White color only.
Q: Is this a trim piece or a full corner post?
A: It is a starter and insert component for corner assemblies, not a full corner post.
Expert Verdict — Reviewed by the SuperArbor Pro Desk
Check the corner for plumb before fastening the starter and insert, since any bow in the corner shows up along the entire trim line. Keep fasteners centered in slots where present so the assembly can move with temperature swings. Order enough single-piece lengths to avoid joints at visible corners when the wall height allows.
Use appropriate ladders and fall protection when working at elevation, and follow the manufacturer's installation instructions.
Order the Mastic Corner Starter & Insert in White, 1/4 in. x 20 ft., for clean, plumb siding corners.
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