GlazeLock Shims: The American-Made Professional Installation Shim Built for Contractors

Part of the America250: Built Here. Built Better. series — celebrating the American makers, manufacturers, and entrepreneurs behind every FLI Products innovation.

Every contractor, glazier, and serious DIYer knows the frustration of a bad shim. Wood shims compress, split, and rot. Cheap plastic shims crack under load or slip out of position. And when a shim fails — on a window, a door frame, a tile installation, or a glass panel — the consequences range from a callback to a structural problem.

GlazeLock was designed to end that frustration. And it was designed and manufactured right here in the United States.

GlazeLock Shims are professional-grade, interlocking U-shaped horseshoe plastic shims engineered for window, door, tile, glass, and structural installation applications. They interlock for precise thickness control, resist compression and rot, and deliver the kind of consistent, reliable performance that professional installers demand.

Built in America for American Contractors

GlazeLock Shims are manufactured in the United States by GlazeLock — an American company dedicated to solving the installation problems that contractors face every day on the job site. GlazeLock brings engineering precision and material science expertise to a product category that has been underserved by cheap imports and inconsistent wood alternatives for decades.

The result is a shim system that professional installers trust because it performs consistently, every time, on every job:

• Interlocking design — U-shaped horseshoe shims stack and interlock for precise, incremental thickness adjustment without slipping
• Compression-resistant — engineered plastic holds its rated thickness under load; no compression, no settling, no callbacks
• Rot-proof and moisture-resistant — performs in wet environments where wood shims fail within a season
• Consistent dimensions — American manufacturing means every shim in every bag meets spec; no variability between production runs
• Multiple thicknesses — available in a range of sizes to cover every installation scenario
  

Where GlazeLock Shims Work

GlazeLock's interlocking horseshoe design makes it the professional's choice across a wide range of installation applications:  

• Window installation — shimming window frames plumb, level, and square in rough openings
• Door installation — setting door frames and pre-hung doors with precision alignment
• Glass and glazing — setting glass panels, storefronts, and curtain wall systems at precise heights
• Tile installation — leveling tile substrates and setting tile at consistent heights
• Structural applications — shimming beams, posts, and structural members to precise elevations
• Appliance leveling — setting refrigerators, dishwashers, and appliances level on uneven floors
• Furniture and cabinetry — leveling base cabinets, furniture, and fixtures on uneven surfaces

Tom Whitaker spent 40 years in manufacturing and has done more than his share of home improvement projects. His take on GlazeLock is practical:

"A shim is one of those things you don't think about until it fails. Wood shims rot, compress, and split. Cheap plastic shims crack. GlazeLock interlocks and holds — I've used them on window installations and they stay exactly where you put them. Made in America, built for the job." — Tom Whitaker, FLI Products Advisor

Why Contractors Choose American-Made Shims

The shim category is dominated by wood and cheap import plastic — both of which create problems that cost contractors time and money:

• Wood shims compress under load, absorb moisture, rot in wet applications, and split during installation — creating inconsistent results and callbacks
• Import plastic shims use lower-grade resins that crack under load, have inconsistent dimensions between production runs, and lack the interlocking design that prevents slippage

GlazeLock eliminates all of these failure modes with American-made engineering and material quality:

• No compression — holds rated thickness under sustained load
• No rot — performs in wet, humid, and exterior applications
• No slippage — interlocking design keeps shims in position during and after installation
• No variability — consistent dimensions from bag to bag, job to job

For contractors, that consistency translates directly to fewer callbacks, faster installations, and a professional result that holds up over time.

Why Retail Buyers Choose GlazeLock

For retail buyers in the construction, hardware, and contractor supply categories, GlazeLock delivers the domestic supply chain advantages that import alternatives can't match:

• 7–30 day domestic replenishment vs. 90–140 day overseas lead times — critical for contractor supply categories
• No tariff exposure — stable, predictable pricing for hardware buyers
• Consistent quality — American manufacturing means every bag meets spec
• Professional credibility — a product that contractors trust and recommend drives repeat purchase
• Made in USA story — a differentiator at Lowe's, Home Depot, Menards, Ace Hardware, and contractor supply channels

FLI Products and the Walmart Open Call

GlazeLock is part of FLI Products' commitment to the Walmart Open Call program — Walmart's annual event connecting American-made products with Walmart buyers for potential shelf placement. American-made professional installation products like GlazeLock represent exactly what Walmart's hardware and contractor supply buyers are looking for.

Learn more at corporate.walmart.com.

Follow the conversation: #WalmartOpenCall #MadeInUSA #America250 #GlazeLock

Heard on Made in America

FLI Products is a recurring guest on Made in America with Rita Compton and Michael King — hosted by Rita Compton, known as America's Inventor Lady. Kevin Cody of FLI Products has appeared on multiple episodes sharing the story behind GlazeLock and the FLI Products mission to bring American-made innovations to retail scale.

Listen here: Made in America Podcast

Where to Buy GlazeLock Shims

GlazeLock Shims are available at the retailers you already trust:

• Walmart — in-store and online
• Amazon
• Lowe's
• Tractor Supply
• Target
• Wayfair
• Zoro
• Best Buy
• Wingra Direct
• Newegg
• The BBQ Superstore
• West Marine
• And directly at fliproducts.com

Part of a Bigger Story

GlazeLock is one of 18 American-made products in the FLI Products portfolio. Explore the full America250 series:

• America250: Built Here. Built Better. — The FLI Products Story
• AnchorStake: Planting a Stake in American Manufacturing
• Blade Guard: Built by Rogers Manufacturing Since 1891
• CordSafe: Weatherproof Cord Covers by Rogers Manufacturing
• CrateMate: American-Made Storage Crates by Rogers Manufacturing
• Flex Strainer: American-Made 2-in-1 Sink Strainer by Darter Plastics
• Shop All Made in USA Products

Shop GlazeLock Shims — Made in USA →

Frequently Asked Questions

Where are GlazeLock Shims made?

GlazeLock Shims are made in the United States by GlazeLock, an American manufacturer and FLI Products partner specializing in professional installation products.

What are GlazeLock Shims used for?

GlazeLock Shims are used for window installation, door installation, glass and glazing, tile installation, structural shimming, appliance leveling, and cabinet and furniture leveling. The interlocking U-shaped horseshoe design provides precise, stable thickness adjustment for any installation application.

How do GlazeLock interlocking shims work?

GlazeLock's U-shaped horseshoe shims stack and interlock with each other, allowing precise incremental thickness adjustment without slipping. The interlocking design keeps shims in position during and after installation — unlike wood shims or non-interlocking plastic alternatives.

Are GlazeLock Shims better than wood shims?

Yes. Wood shims compress under load, absorb moisture, rot in wet applications, and split during installation. GlazeLock plastic shims hold their rated thickness under sustained load, resist moisture and rot, and deliver consistent dimensions from bag to bag.

Are GlazeLock Shims available at Walmart?

Yes. GlazeLock Shims are available at Walmart in-store and online, as well as at Amazon, Lowe's, Zoro, and other major retailers.

What is the Walmart Open Call program?

Walmart Open Call is Walmart's annual event connecting American-made products with Walmart buyers for potential retail shelf placement. Learn more at corporate.walmart.com.

Who is Tom Whitaker?

Tom Whitaker is a retired manufacturing professional with 40 years of hands-on experience in construction, home improvement, and outdoor projects. Learn more at fliproducts.com/pages/learn-from-tom.