This is part of our Designing with ICF: A Technical Guide for Architects & Engineers.
Direct Answer: To guarantee the performance of the building envelope, you must tighten your specification language. Generic specifications lead to contractor "value engineering" to inferior block systems. Below is the essential language for Section 03 11 19.
Part 2: Products
2.1 INSULATING CONCRETE FORMS
* A. Manufacturer: Element ICF.
* B. Description: Modular formwork consisting of two 2.625-inch thick EPS panels connected by high-density polypropylene webs.
* C. Core Width: [Select: 4", 6", 8", 10", 12"] inches nominal.
* D. Web Spacing: Webs shall be spaced no more than 6 inches on center to prevent form bulging.
* E. Comparison: Substitutions must demonstrate equal or greater web density (ties per square foot) and interlock strength.
Part 3: Execution (The Critical Mix)
3.1 CONCRETE MIX DESIGN
* A. Aggregate: Maximum size shall be 3/8 inch (Pea Gravel). Coarse aggregate (3/4" or larger) is prohibited to prevent bridging.
* B. Slump: Concrete shall be placed at a slump of 5 to 6 inches at point of discharge. (Note: Use plasticizers/superplasticizers to achieve flow, do not add excess water).
* C. Strength: Minimum compressive strength of [3000 / 4000] psi at 28 days.
3.2 PLACEMENT AND CONSOLIDATION
* A. Lifts: Place concrete in continuous lifts not exceeding 4 feet in height per hour to prevent blowouts.
* B. Vibration: Mechanically consolidate concrete using an internal pencil vibrator (max 1-inch head diameter).
* C. Prohibition: External form vibration (banging on walls) is not an acceptable method of consolidation.
Quality Control Requirement
1.4 QUALITY ASSURANCE
* A. Installer Qualifications: The work must be performed by a firm with minimum 5 years of experience in ICF construction and capable of showing certification from the manufacturer (Element ICF).
* B. Pre-Installation Conference: Conduct a meeting at the site 2 weeks prior to pour to verify bracing plan, pour strategy, and mix design.
