What is ICF?
ICFs combine simplicity, strength, and energy efficiency
ICFs are basically stay-in-place forms for pouring concrete wall
ICF System Basics
- ICF Form System
- Wall Structure
- Air Barrier
- Vapor Barrier
- Interior and Exterior Finish Anchorage
History of Concrete Use and Development of ICF Technology
Historical Use of Concrete
The Pantheon (125 AD)
One of Rome’s original structures used cast-in-place concrete. It has been in continuous use since the 7th century and is still the world’s largest un-reinforced concrete dome.
The Pantheon obviously did not have insulated forms, but has proven the strength and durability of poured-in-place concrete and that is the basis behind ICF.
The Leland Standford Jr. Museum (1894 AD)
The Leland Stanford Jr. Museum was one of the first projects in the U.S. to use “new” technology of cast-in-place concrete with reinforced steel as designed by Ernest L. Ransome, structural engineer.
Utilizing this innovative approach, the building was completed in two-thirds the time and at half the cost of an equivalent masonry building.
Development of Insulated Concrete Form Technology
- Early ICFs first appeared in the late 1960s, with growth of concrete construction.
- Imported from Europe in late 1970s to Canada.
- The 1980s saw a number of different forming systems enter the market.
- The 1990s saw a significant increase in ICF manufacturer’s bringing new systems to the market in the United States.
- Increasing energy costs over the past ten years have encouraged rapid growth of ICFs in the United States.
- The new millennium ushered in the next generation of insulated concrete forms.
- ICFs have grown steadily in popularity as an alternative building system.
Broad Use of ICFs
- ICF systems are in now in use worldwide
- 45 current suppliers of ICF systems in the USA with 10 of these companies combine for over 90% of the total sales within the ICF industry.
- Commercial use includes offices, hotels, schools, churches, hospitals, etc.
- Used commonly in single and multi-family homes.
Basics of ICF Construction
ICF Wall Assembly
Insulated concrete forms consist of two panels of foam insulation made of expanded (EPS) or extruded (XPS) polystyrene.
The lego-like Styrofoam forms are easily assembled and lock together to create the wall.
The reinforcing steel (rebar) is held in place by “webs”, usually manufactured from recycled plastic, nylon, or metal inserts, and becomes a permanent reinforcement of the wall.
Horizontal rebar is added as the blocks are stacked; vertical rebar is added pre-pour.
Window and Door Bucks
Window, door or other openings in the wall are pre-assembled using treated wood. The most common buck is built slightly larger than the actual door or window to allow for leveling and adjustments.
This type of bucking system holds securely to the wall when concrete is vibrated into the dovetail grooves. This system also prevents air and water infiltration.
Custom metal frames are available to be set and poured into the concrete prepped and ready for door and glazing installations.
Concrete is poured into the forms using a pump truck.
ICF walls are load-bearing, supporting beams and eliminate the need for steel columns. In some cases the amount of columns, light gauge metal framing and insulation that is replaced by an ICF wall is enough to pay for the wall.
Bar joist with metal decking is the most common commercial floor and roof system and easily integrates with ICF walls.
The Angelo State University project used hollow core planks on eight floors. Each floor averaged 11,000 SF with a three to four day installation schedule.
Wood and concrete are easily integrated.
In comparison to structural steel, ICF is very competitive in mid to high rise structures.
West Village Suites located in Hamilton, Ontario received LEED® Canada’s highest honor by attaining a Platinum Rating. The Student Housing Complex used a variety of green building products to meet its extraordinary goal, including NUDURA Insulated Concrete Forms.