Mark Turnquest, CIPM
ICF BLOCK VS. CMU (CONCRETE MASONRY UNIT)
Using ICF block will reduce any construction cost vs. CMU and will reduce the overall project construction time, increase the safety of the construction site and process. It will also lower project operating expenses. ICF benefits the overall construction cost by reducing the time and labour cost. This allows you to lease or occupy the building, producing a rate of return on investment sooner both short and long term. The average size of an ICF block is 18" X 48". One ICF block is equivalent of 6 CMU's. The features of an ICF block eliminates the need for several products and construction steps which are required when doing CMU installation. The strong interlocking of an ICF block and its light weight, makes stacking fast and easy. eliminates the labour of mortaring between each CMU and reduce the number of skilled masons required.
The ICF block comes with already locked in vinyl inserts which provides easy receiving and lock in of the #5 rebar steel, making it unnecessary for use of ties for steel. The insert also serves as furring strips for interior and exterior finishes, eliminating the need for adding additional furring strips required for CMU. These inserts include hard points with a pullout of up to 500lbs and are identified by scoring marks 8" on center on the block itself. The panels stay in place providing permanent insulation and ready to finish surface for stucco , brick and siding. This eliminates the problem of stair step cracking with CMU used with stucco. Cutting an ICF block is easy to do with a simple hand saw, compare that to the process of cutting a concrete block.
The light weight of the ICF block makes it much safer for workers on the project site. This results in fewer project site injuries. To further propel the construction project there are additional form blocks such as 90' degree and 45'degree corners, brick ledge and double tapper top forms. ICF walls can be engineered to bear greater loads than concrete CMU loads, vertically and horizontally. ICF can also be used to share the loads that would otherwise be required to rest on steel or concrete columns. Also, elevator shafts and walls under escalators can be formed by ICF blocks. All of these options leads to the reduction of construction time when contrasting CMU's. Faster easier construction time means fewer skilled labourers, fewer overall labour hours less construction loan interest and faster occupancy.
These augmented savings help to mitigate the cost of using green and alternative forms of construction. The finish ICF structure is highly energy efficient, comfortable, quiet and safe. EPS (expandable polystyrene) has an R-value of R-4 per inch when combined with the thermal mass of the concrete and the extreme reduction in air infiltration, translate into a performance R-value of R-30-50.
This built in energy efficiency reduces energy cost annually when compared to CMU structures providing savings over the life of the building. The thermal mass of the insulation of concrete walls provides a quiet, comfortable, interior for occupants. the internal temperature is more stable and comport.
ICF structures are resistance to hurricanes and tornadoes and fire.