The Simpson GWL Lathing Washer is a steel washer engineered for attaching lath to wall surfaces in preparation for scratch coat, brown coat, and stucco applications. Designed by Simpson for use with both the G3 gas-actuated fastening tool and the GCN-MEPMAGKT gas-actuated concrete nailer tool, this 1-inch diameter washer is held onto the single-shot nosepiece of either tool via a compatible magnetic ring, then secured to concrete or CMU substrate using gas-driven pins that fasten directly through the washer - delivering fast, consistent lath installation without interrupting workflow.

Key Features

• Wide 1-inch diameter holding surface - distributes holding force across a broad contact area, keeping lath firmly secured to the wall during and after installation
• Snaps directly onto the G-422 or GMR-2 magnetic ring (sold separately) - no extra tools needed to load the washer onto the nosepiece, keeping installation fast and hands-free
• Compatible with two gas-actuated fastening tools - works with both the G3 and the GCN-MEPMAGKT, giving contractors flexibility across different jobsite setups
• Fastened through by gas-driven pins - pins drive straight through the washer into concrete or CMU substrate, creating a secure, flush attachment without pre-drilling or additional hardware
• Steel construction - provides the durability and rigidity needed to hold lath reliably against the substrate through the plastering process
• 1,000 washers per package - high-quantity packaging reduces resupply interruptions on large stucco and plastering projects

Why This Product

• Designed specifically for gas-actuated lath installation - the GWL washer is purpose-built to work with Simpson gas-actuated tools and gas-driven pins, so every component in the system is engineered to work together rather than relying on mismatched parts
• Tool-free nosepiece loading speeds up the work - because the washer simply snaps onto the magnetic ring already mounted on the tool, crews can reload and keep driving without stopping to adjust or hand-tighten anything
• Suitable for both concrete and CMU substrates - whether the project involves poured concrete walls or concrete masonry unit construction, the same washer handles both applications without substitution or modification
• Streamlines the full stucco prep process - by holding lath securely in place for scratch coat, brown coat, and stucco overlay in a single fast step, this washer helps reduce labor time across the entire exterior cladding workflow

Specifications

• Manufacturer: Simpson Strong-Tie
• MPN: GWL-100
• Diameter: 1 inch
• Material: Steel
• Quantity: 1,000 per carton

Approved Applications

• Attaching lath to concrete substrate
• Attaching lath to CMU (concrete masonry unit) substrate
• Preparing wall surfaces for scratch coat application
• Preparing wall surfaces for brown coat application
• Preparing wall surfaces for stucco overlay
• Use with G3 gas-actuated fastening tool (with G-422 magnetic ring, sold separately)
• Use with GCN-MEPMAGKT gas-actuated concrete nailer tool (with GMR-2 magnetic ring, sold separately)

Frequently Asked Questions

Which tools are compatible with the GWL-100 lathing washer?

The GWL-100 is designed for use with both the G3 gas-actuated fastening tool and the GCN-MEPMAGKT gas-actuated concrete nailer tool. The washer is held onto the single-shot nosepiece of the G3 using the G-422 magnetic ring, or onto the GCN-MEPMAGKT using the GMR-2 magnetic ring (both magnetic rings sold separately).

What type of fastener is used to attach the GWL-100 washer to the substrate?

The GWL-100 washers are attached to concrete or CMU substrate using gas-driven pins (GDP), which fasten directly through the washer to secure the lath to the wall surface.

Do I need additional tools to install the GWL-100 washer onto the tool's nosepiece?

No extra tools are needed. The GWL-100 easily snaps onto the magnetic ring (G-422 or GMR-2) on the nosepiece of the tool, making setup quick and straightforward.

How many lathing washers are included in one package of GWL-100?

Each carton of GWL-100 contains 1,000 lathing washers, making it well-suited for larger lath installation projects requiring consistent, efficient fastening.

Note: Product dimensions and/or thread length may differ from picture. Please see the item description above for specifications.