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MASOPZ™ Mudsill Anchor for Panel Form

The latest in our growing line of offsite construction solutions, the MASOPZ mudsill anchor is an ideal anchor for factory-built, sheathed wall panels that are anchored to concrete foundations utilizing panel forms. The advantages of the MASOPZ are similar to those of our popular MASAP™ connector, except that with the MASOPZ there’s no need for additional field-installed blocking to complete the installation for sheathed walls. After the MASOPZ is installed and the concrete is cured, sheathed wall panels are craned into place without the hassle of trying to align sill plate bolt holes with cast-in-place anchor bolts. In addition, the MASOPZ saves labor over post-installed anchors by eliminating the need for a separate crew to drill and set anchors. The MASOPZ comes standard with our ZMAX® coating, is designed to work with panel forms, and is code listed by ICC-ES under the 2021 IBC and IRC.

Key Features

  • Attaches easily to the concrete form for quick installation
  • Strategic nail hole placement and bend-line locations work with sheathing flush or overhanging at foundation edge
  • Eliminates the labor costs of drilling sill plates and aligning holes for anchor bolts
  • Raised embossments surrounding the nail holes facilitate speedy nail installation with a power framing nailer
  • Patent pending


  • 16 gauge


  • ZMAX coating


  • Warning: This product is not compatible with all power framing nailers and nails. Do not use any tool that has been altered or modified. Before using the MASOPZ with any power framing nailer, you must determine whether the nailer is compatible with the MASOPZ product. If the nail is unable to be installed in accordance with the information above, or if the nail is not centered in the fastener feature, do not use that power framing nailer with the MASOPZ product. Wear eye protection and hand protection. Follow the manufacturer’s safety precautions when using any power nailer.
  • Important Notes for Installers: This product is compatible with many power framing nailers and nails.
    • Use only nails with concentric, full-round heads that comply with ASTM F1667.
    • Do not use 28˚ wire-weld nails, or any nails with offset, clipped, or D heads.
    • Place tool’s nosepiece in the MASOPZ fastener feature. The outer ring of the power framing nailer nosepiece should fit within the outer ring of the fastener feature. Install a few nails to ensure nail acceptance. The nail should be seated into the center of the MASOPZ fastener feature. Adjust air pressure or drive depth to achieve the correct nail placement. Operate framing nailers in single-drive, sequential actuation mode only.
  • Use all specified fasteners; see General Notes.
  • Concrete shall have a minimum f’c = 2,500 psi. Use a concrete vibrator or other means to ensure full consolidation of concrete around the part.
  • The MASOPZ is designed to be attached through wood structural panel sheathing. For direct attachment to the sill plate, use MASAP.
  • Spalling — full loads apply for spalls up to a maximum height of 1" and a maximum depth of 5/8". Any exposed portion of the mudsill anchor must be protected against possible corrosion.
  • The minimum MASOPZ end distance to the center of the part is 6", and the minimum center-to-center spacing is 12" for full load. For reduced center-to-center spacing and/or end distance, contact Simpson Strong-Tie for reduced loads.
  • For a continuous load path, uplift connectors should be installed on the same side of the wall as the MASOPZ.
  • To install in severe corrosion environments, refer to Guidelines for Selecting Materials and Coating for additional considerations.

Related Literature

Product Information Table

Fastener Production Information and Stuff & Things
New products
Model No. Ga. Coating Packaging Qty.
MASOPZ-R25 16 ZMAX® 25

Prescriptive Spacing for MASOPZ to Replace Mudsill Anchor Bolts

Model No. Anchor Bolt Size to Replace Anchor Bolt Spacing to Replace MASOPZ Spacing
DF/SP 2x Sill Plate SPF/HF 2x Sill Plate
Wind and SDC A&B SDC C–E Wind and SDC A&B SDC C–E
MASOPZ 1/2" diameter 6' o.c. 6'–0" 6'–0" 6'–0" 6'–0"
4' o.c. 4'–0" 4'–0" 4'–0" 4'–0"
MASOPZ 5/8" diameter 6' o.c. 5'–0" 5'–0" 4'–10" 4'–10"
4' o.c. 3'–4" 3'–4" 3'–2" 3'–2"
  1. Detached one– and two– family dwellings in SDC C may use “Wind and SDC A&B” spacing per 2012/2015/2018/2021 IBC® Section 1613 and IRC® Section 301.2.2.
  2. Spacing is based on the parallel-to-plate (F1) load direction only.
  3. 5/8" anchor bolts required for Seismic Design Category E.
  4. The prescriptive spacing shown for DF/SP 2x sill plates requires the use of WSP consisting of OSB, Structural 1 plywood, or plywood of a species known to have an assigned specific gravity (SG) equal to or greater than 0.50.

Allowable loads

Model No. Sill Size Fasteners (in.) Allowable Loads
Uncracked Cracked
Wind and SDC A&B6 SDC C–F6 Wind and SDC A&B6 SDC C–F
Uplift F1 F2 Uplift F1 F2 Uplift F1 F2 Uplift F1 F2
DF/SP Sill Plate with WSP sheathing8
MASOPZ 2x4, 2x6, 3x4, 3x6 (7) 0.148 x 2 1/2 970 1,295 465 850 1,295 465 675 1,295 465 595 1,190 465
HF/SPF Sill Plate with WSP sheathing
MASOPZ 2x4, 2x6, 3x4, 3x6 (7) 0.148 x 2 1/2 920 1,120 405 850 1,120 405 675 1,120 405 595 1,120 405
  1. Loads have been increased for wind or earthquake loading, with no further increases allowed. Reduce where other loads govern.
  2. Concrete shall have a minimum compressive strength of f'c = 2,500 psi.
  3. Allowable loads are based on a minimum stem wall width of 6"
  4. For simultaneous loads in more than one direction, the connector must be evaluated using the Unity Equation, as described in General Instructions for the Designer.
  5. Minimum wood structural sheathing thickness shall be 3/8" and maximum sheathing thickness shall be 1/2". Refer to installation images for additional requirements.
  6. Detached one– and two– family dwellings in SDC C may use “Wind and SDC A&B” spacing per 2012/2015/2018/2021 IBC Section 1613 and IRC® Section 301.2.2.
  7. For designs under the 2015/2018/2021 IBC, sill plate size shall comply with the shearwall requirements of the 2015 /2021 Special Design Provisions for Wind and Seismic.
  8. The tabulated values for DF/SP sill plates require the use of WSP consisting of OSB, Structural 1 plywood, or plywood of a species known to have an assigned specific gravity (SG) equal to or greater than 0.50. For other WSP conditions used in conjunction with DF/SP sill plates, use HF/SPF tabulated values.
  9. Fasteners: Nail dimensions are listed diameter by length. For additional information, see Fastener Types and Sizes Specified for Simpson Strong-Tie Connectors.
  10. Contact Simpson Strong-Tie for load reductions associated with gaps larger than 1/8" between the sheathing and concrete.

Code Reports & Compliance