Hidden Granite Countertop L Bracket Installation Instructions

Top-mount hidden support for granite, quartz, stone, and wood countertop overhangs on knee walls, pony walls, kitchen islands, and cabinet bases. Nothing shows below the overhang.

Installation

This guide walks you through installing your new Hidden Granite Countertop L Brackets with clarity and confidence. Each step is clearly explained, with the safety notes and tips you need for a secure, professional result — whether you're an experienced contractor or tackling this as a DIY project. Before you begin, review all the steps and confirm you have the required tools, fasteners, and safety equipment on hand.

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What's Included

• 1x Hidden Granite Countertop L Bracket
• 6x #14 x 2½" Phillips Flat Head Wood Screws

Safety Information

• Use the correct tools for each step.
• Wear protective eyewear and proper safety equipment.
• When using tools or modifying anything, follow the manufacturer's instructions and user manuals.
• Always use common sense and follow good construction practices.
• Ask a professional when installing brackets for load-bearing applications.
• Always mount brackets to a structure able to support the brackets and the weight that may be applied to them.
• Any use of this product other than its intended use is not recommended.

Full Product Details

Specifications, sizing and quantity tables, videos, and every product document live on the product page.

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(1) Gloves  (2) Safety Glasses  (3) Measuring Tape  (4) Pencil  (5) Bubble Level  (6) Phillips Screwdriver  (7) Mallet  (8) 1" Chisel  (9) Drill with 9/64" Bit  (10) Hand Saw  (11) Caulking Gun  (12) Hand Router (optional — Top Bearing Flush Trim bit, ½" cutting depth)

STEP 1Mark the Mounting Locations

Measure and mark the mounting locations on the cap of your knee wall. Center each bracket on a vertical stud so the lower back-plate screw anchors into the stud. Place one bracket 4"–6" from each end (4" recommended), then space the remaining brackets evenly between 16" and 24" on center. Any spacing in that range is acceptable; 24" is the maximum.

WARNING — Spacing carries the rating. Brackets must be spaced 16"–24" on center and centered on studs. Wider spacing voids the rated working load.

STEP 2Cut the Mounting Channel

Create a ½" deep, 2.5" wide recessed channel in the cap of the knee wall at each mark. Power tools: a Top Bearing Flush Trim router with a ½" cutting depth trims the material cleanly. Manual tools: saw along each line to a depth of ½", then remove the wood between the lines with a 1" chisel. The channel must be flat and clean so the bracket seats flush — this keeps the countertop level and stops the bracket from shifting.

STEP 3Install the Bracket

Set the bracket into the channel and fasten the top leg to the wall cap with the included #14 x 2½" Phillips Flat Head Wood Screws. Fasten the back plate to the rear face of the knee wall, anchored into the header and/or vertical stud. The horizontal leg must bear fully on the wall cap.

WARNING — Anchoring carries the rating. Top-mount only. The back plate must anchor into the header and/or a vertical stud; the top leg must bear fully on 2x4 or 2x6 framing. Never mount to drywall, to a cabinet face, or in a front-mount position — this bracket is not designed for front mounting and will fail if installed that way. Metal studs must be reinforced with solid wood blocking.

Pro tip: Pre-drill with a 9/64" bit to avoid splitting the wood.

STEP 4Check for Level

Use a bubble level to confirm the bracket is flush with the wall cap. Shim as needed. Every bracket across the span should sit at the same height — an uneven bracket creates a stress point on the countertop.

STEP 5Apply Adhesive and Set the Countertop

Before setting the countertop, run a bead of high-quality silicone adhesive along the top face of each bracket. Lower the countertop into place, confirm it sits level, and allow the adhesive to cure per the manufacturer's instructions before applying heavy loads.

On a cabinet base the bracket needs solid wood to sit on and fasten to. A 2x6 header on edge along the back of the cabinet box provides both. Rated working load on cabinet-base installations is 300 lbs per bracket when installed as shown.

STEP 1Install the 2x6 Backing

When mounting on cabinet boxes, add backing to provide structural support and something to fasten to. Install a 2x6 header on edge along the back of the cabinet box — in this example, in the back of every box. The bracket's horizontal leg bears on the header (1½") plus the ¾" plywood box top.

STEP 2Mark the Mounting Locations

Place one bracket 4"–6" from each end (4" recommended), then space the remaining brackets evenly between 16" and 24" on center, 24" maximum.

STEP 3Cut the Mounting Channel

Create a ½" deep, 2.5" wide recessed channel above the cabinet base header where each bracket will sit. Power tools: Top Bearing Flush Trim router, ½" cutting depth. Manual tools: saw along each line to ½" deep, then chisel out the material between the lines. The channel must be flat and clean so the bracket seats flush.

STEP 4Install the Bracket

Set the bracket above the cabinet base, fully supported by the 2x6 header behind the box. Fasten the back plate into the header and draw it snug to the header face before driving the top screws. Then drive the four top-leg screws. Ensure proper blocking is in place.

WARNING — Anchoring carries the rating. The back plate must be fastened into the 2x6 header and the horizontal leg must bear on the header and box top. Never front-mount this bracket or fasten it to the cabinet face or plywood alone.

Pro tip: Pre-drill with a 9/64" bit to avoid splitting the wood.

STEP 5Check for Level

Use a bubble level to confirm the bracket is flush with the cabinetry. Shim as needed for perfect alignment.

STEP 6Apply Adhesive and Set the Countertop

Run a bead of high-quality silicone adhesive along the top face of each bracket, then set the countertop and allow the adhesive to cure before loading.

Mounting surface. Iron Supports brackets are engineered to support significant loads but must be properly installed to perform safely. Fasten to 2x4 or 2x6 wood framing, a 2x6 cabinet header, continuous wood blocking, or double-stud construction so every fastener is fully embedded in solid wood. Do not over-tighten or strip the screws. For metal studs, reinforce by piggybacking a wood stud or inserting a wood stud into the C-channel.

Spacing. Brackets are typically spaced 16" or 24" on center to align with standard stud framing. Any spacing between 16" and 24" is acceptable; 24" on center is the maximum. The listed capacities assume evenly distributed static loads — concentrated edge loads, such as leaning or sitting on a bar edge, call for tighter spacing.

Incorrect installation. This bracket is not designed for front mounting. Installing it in a front-mount position will result in failure. Always follow these instructions; proper installation is the responsibility of the installer.

Spec Drawings (PDF) — by size: 10"  •  12"  •  14"  •  16"  •  18"  •  20"  •  22"

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