Made in the USA • Patented • 100% No Breakage Money Back Guarantee
What Is the JAWS® Large Screed Chair?
JAWS® Large is a stay-in-place concrete screed chair designed to support 1.5″ to 2.0″ wide aluminum, magnesium, or steel screed rails for accurate grade control and consistent screed setup.
The patented JAWS® “teeth” hold the screed rail securely during placement and release easily when moving down the pour line. The internal “fins” hug the mounting structure so the chair will not bounce off rebar or rod during placement.
Designed For
- Slab-on-grade construction
- Elevated slabs
- Concrete overlays
- Vapor barrier slabs
- Bridge decks and infrastructure projects
- Super flat floors requiring FF/FL compliance
Ideal for use on projects requiring compliance with ACI 302.1R-04, ACI 117 and ASTM E1155. Iowa DOT approved.
Key Specifications
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Product Number: 082412JAW2 (Large)
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Overall Height: 3.50″
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Supports: 1.5″–2.0″ aluminum, magnesium, or steel screed rails
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Minimum Height (example rail): 5-1/2″ (140 mm) from bottom of chair to finished elevation using a 2x4 aluminum screed
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Fits Mounting Structures: 3/8″–5/8″ (10–16 mm), 1/2″ ideal
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Load Capacity: Holds up to 1,000 lbs
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Spacing: Every 3–4 ft depending on rail length and sub-grade conditions
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Coverage: 100 JAWS Large per bag (approx. 3,000 sq ft / 278 m²)
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Material: Impact-resistant medical grade polypropylene
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Installation Tool: Use MAKO Driver to achieve consistent, accurate placement every time
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Non-conductive / Non-corrosive: Will not corrode even in extreme environments
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Country of Origin: Made in USA
Compliance, Approvals & Patents
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Standards: ACI 302.1R-04, ACI 117, ASTM E1155
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Approvals: Iowa DOT approved (other states pending)
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Patents: 8,096,182 | 8,544,182 | Patent Pending
How It Works
- Insert mounting structure (rebar, rod, stake, etc.) between 3/8″–5/8″.
- Slide JAWS Large onto mounting structure until seated.
- Use MAKO Driver to set elevation accurately and consistently.
- Place 1.5″–2.0″ screed rail into the JAWS “teeth” to secure.
- Pour and strike concrete using hand or mechanical screeds.
JAWS Large is designed as a stay-in-place form and remains in the slab after placement.
Why Contractors Choose JAWS Large
- Designed for wider 1.5″–2.0″ aluminum, magnesium, or steel screed rails
- JAWS “teeth” hold rail securely yet release easily as you move down the pour line
- Internal fins hug rebar/rod to prevent bounce-off during placement
- Non-conductive and non-corrosive for bridge decks, waterways, and power plant projects
- Virtually unbreakable under normal placement conditions
Common Applications
- Slab-on-grade
- Elevated slabs
- Concrete overlays
- Vapor barrier installations
- Industrial and commercial floors
- Infrastructure projects
Frequently Asked Questions
What rail sizes does JAWS Large support?
JAWS Large is designed to support 1.5″ to 2.0″ aluminum, magnesium, or steel screed rails.
What mounting structures can be used?
JAWS Large fits mounting structures from 3/8″ to 5/8″ including rebar, threaded rod, stakes, dowels, PVC, or conduit.
How far apart should JAWS Large be spaced?
Typically every 3–4 feet depending on rail length, screed weight, and sub-grade conditions.
Can JAWS Large be left in the slab?
Yes. JAWS screed chairs are designed as stay-in-place forms made from medical grade polypropylene and will not corrode.
Can it be used with hand or mechanical screeds?
Yes. JAWS Large works with both hand and mechanical screeds.
Downloads
JAWS Large Product Data Sheet
