5 Common Misconceptions About ICF Construction
Contractors and architects looking to build energy-efficient, disaster-resistant, comfortable, and durable structures must not let past misconceptions about insulated concrete form (ICF) construction detour them from using this innovative product. ICF construction, like one built with Fox Blocks, is attractive, saves money over time, is fast and simple to install, energy-efficient in all climates, and contributes towards disaster-resistance.
What is ICF Construction?
Building with ICF walls involves dry-stacking ICF blocks, like building with Lego bricks. An ICF block is two rigid insulation panels ( often 2.5" or more thick of expanded polystyrene) held together with plastic cross-ties. The ICF blocks are available in various concrete core widths and the cross-ties support the installation of rebar horizontally and vertically. Once the interlocking ICF blocks form the wall, concrete is placed and cures, resulting in a permanent exterior framework, ready for finishes, plumbing and electrical.
ICF construction creates modern structures that are energy-efficient, durable, disaster-resistant, and have good indoor environmental quality (IEQ). ICF construction is also strong, flexible, fast and easy to install. Unfortunately, even with these many benefits, some architects and contractors are reluctant to utilize it due to misconceptions about ICF construction.
Five Misconceptions about ICF Construction
1. ICF Buildings are Plain or Unattractive
Untrue. The strength and flexibility of ICF construction can accommodate most any building style, size, and plan. In addition, ICF is easy to cut and shape and can include customized designs, such as large openings, cathedral ceilings, curved walls, long ceiling spans, and custom angles. Once complete, an ICF building can look just like a wood-framed structure. However, an ICF creates a high-performance wall which has a different thickness than a minimum- code wood-frame wall. ICF walls may be 12"+ in thickness, while a minimum-code wood framed wall is 4.5 inches.
For an ICF plan to maintain the desired interior square footage, it is necessary to increase the overall plan dimensions to account for the thicker exterior walls. Also, windows and doors will require wider jamb extensions to accommodate the increased wall thickness. Converting a traditional wood-frame plan to ICF would require the services of an architect.
ICF walls are compatible to any exterior finish - stucco, siding, masonry, simulated stone, etc. All finishes can be directly installed to the ICF following manufacturers specifications.
Home built with Fox Block ICF construction
2. ICF Construction is Costly
While ICF construction may cost 3 to 5 percent more than wood-frame construction up front, the long-term financial advantages of building high-performance ICF walls can more than make up for the higher construction costs. ICF construction provides life-time savings with lower utility bills and HVAC operating costs, reduced labor costs, higher rents, improved occupancy, and added long-term value to a building project over similar wood-frame projects.
3. ICF Construction is Complicated and Time-Consuming
The opposite is true. ICF construction is typically fast and easy, which saves contractors time and money. For instance, Fox Blocks ICF is an all-in-one wall assembly that combines five building steps into one, including air barrier, vapor retarder, structure, insulation, and attachment. Combining five steps into one, with one contractor accelerates project delivery by eliminating the need to coordinate multiple trades while achieving all of the wall assembly’s goals. A faster weather tight building with ICFs, means faster project completion and occupancy.
4. ICF Construction is Only Useful in Cold Climates
This is a false statement. In all climates, ICF construction builds structures that are more energy efficient and less drafty than either wood or steel structures, which saves energy and money and improves the comfort for the occupants. The continuous double insulation layers around the concrete thermal mass of ICFs produce structures with a very efficient thermal building envelope. Fox Blocks ICF walls have no thermal bridging, provide excellent air-tightness, plus control moisture and vapor within the assembly. ICF structures further save money because they need smaller-capacity equipment for the heating, air-conditioning, and ventilating than wood and steel buildings.
5. ICF Construction can Resist Seismic Activity and is Hurricane Resistant
This statement is partially correct. A more accurate statement is that ICF construction can outperform traditional wood-frame construction during a severe hurricane event or seismic activity. Importantly, a report by the Portland Cement Association found that ICF walls have more structural amplitude and stiffness to weather the in-plane shear forces, during severe winds or an earthquake than wood- and steel-framed walls.
Notably, structures built with Fox Blocks ICFs maintain their integrity during intense hurricane winds of over 200 mph and withstand projectile debris moving over 100 mph.
Fox Blocks also contribute towards an earthquake-resistant structure because they create shear walls that stretch the entire height and all sides of the home or building. Steel reinforcing bars attach the Fox Blocks ICF shear walls to the foundation. When an earthquake occurs, the design of Fox Blocks effectively resists severe sideways (lateral) in-plane forces that push the top of the wall one way while the bottom stays either stationary or is forced the other way (racking the wall).
FEMA recognizes ICFs for the construction of safe rooms and community shelters.
As the construction industry adapts to building and energy code changes, ICFs for years have exceeded many aspects of code requirements and still do. As the wood framing industry tries to meet the new code and energy requirement, there is no misconception that Fox Blocks ICFs can provide a much simpler and efficient solution.