The Simpson MASB 16-Gauge Galvanized Masonry Mudsill Anchor by Simpson is a one-piece steel connector designed to anchor a mudsill to concrete block (CMU), poured concrete walls, or slab foundations - serving as a dependable alternative to traditional anchor bolts on stemwall and slab foundation projects. Its unique design mounts directly on forms, making finishing faster and eliminating the common frustration of misplaced or lost anchor bolt hardware.

Key Features

• Anchors mudsill to concrete block, poured walls, or slab foundations - covers the full range of common foundation types, giving contractors a single go-to connector for stemwall and slab applications
• One-piece design with no nuts or washers - fewer loose parts to keep track of on the job site means faster installation and less risk of missing hardware delaying your work
• Mounts on forms and adjusts into position after placement in grouted CMU cell - the flexible positioning window lets crews correct alignment before the grout cures, eliminating costly errors caused by fixed anchor bolt placement
• Mudsill attaches only after concrete grout fully cures - the proper sequencing built into the design protects connection integrity and helps ensure a structurally sound finished assembly
• Compatible with nominal 2x4 and 2x6 sill sizes - fits the two most common mudsill dimensions used in residential and light commercial framing
• Made from 16-gauge steel - provides the structural rigidity needed for reliable mudsill-to-foundation connections in demanding construction conditions
• G90 zinc galvanized coating - delivers extra corrosion resistance to help the anchor hold up in moisture-exposed foundation environments over the long term
• Installs with 10d x 1-1/2 in. nails - uses a standard fastener size that most framing crews already carry, keeping installation straightforward with no specialty hardware required

Why This Product

• Eliminates anchor bolt headaches - because the MASB places and adjusts after the CMU cell is grouted rather than being cast in place beforehand, crews avoid the misalignment problems that make traditional anchor bolts a recurring source of rework on foundation projects
• Versatile across multiple foundation types - a single connector model works for concrete block, poured walls, and slab foundations, reducing the need to source different anchoring solutions for different job conditions
• Streamlined one-piece construction - with no separate nuts or washers to manage, the MASB keeps the installation process clean and efficient, lowering the chance of hardware going missing mid-pour
• Built-in corrosion protection for foundation-level exposure - the G90 galvanized finish addresses the real-world moisture and concrete chemistry conditions that mudsill connections face, supporting long-term performance without additional treatment

Specifications

• Model Number: MASB
• Gauge: 16
• Coating: Zinc Galvanized, G90
• Finish: Zinc Galvanized, G90
• Member Size: 2x4, 2x6
• Install With: 10d x 1-1/2 in. nails
• Country of Origin: United States

Approved Applications

• Anchoring mudsill to concrete block (CMU) foundations
• Anchoring mudsill to poured concrete walls
• Anchoring mudsill to slab foundations
• Stemwall foundation construction

Frequently Asked Questions

What is the MASB mudsill anchor used for?

The MASB is designed to anchor a mudsill to concrete block, poured walls, or slab foundations. It serves as a reliable alternative to traditional anchor bolts, suitable for both stemwall and slab foundation applications.

How do you install the MASB mudsill anchor in a CMU block?

Fill the CMU cell with concrete grout first, then place the MASB into the grouted cell and adjust it into position. Attach the mudsill to the anchor only after the concrete grout has fully cured.

What nail size is required to fasten the mudsill to the MASB anchor?

The MASB should be installed with 10d x 1-1/2 in. nails to properly secure the mudsill to the anchor.

What sill sizes is the MASB compatible with, and what corrosion protection does it offer?

The MASB is compatible with nominal 2x4 and 2x6 sill sizes. It is manufactured from 16-gauge steel with a G90 zinc galvanized coating for extra corrosion resistance, making it suitable for demanding construction environments.