Insulating Concrete Forms (ICF) offered an energy-efficient mode of construction long before sustainability was widely pursued or even understood in the overall construction industry. During the past 15 years, sustainability – and in particular energy efficiency – have taken center stage in society. The construction industry has brought laser-like focus to the problem: a variety of building methods are finally seeing improvements in thermal energy efficiency. While the others were catching up, the thermal properties of ICF remained virtually a constant, until recently. There has been (more or less) one standard thickness of insulation available, and the most widely used insulating form material – expanded polystyrene (EPS) – has remained the same.
In the past few years, however, ICF makers have stepped up their insulating abilities. To stay ahead of the sustainability curve, they have pursued two different strategies for getting a higher effective R-value from their wall systems. The resulting systems, called Enhanced Performance ICF (EPICF), deliver the advantages of traditional ICF along with a significant increase in energy efficiency. Continue reading →
Case Study: Building with EPICF
One of the first projects built with the new 8.25 cm (3.25 inch) EPICF blocks is a 930 m2 (10,000 sf) two-story office building in Collingwood, ON. The designer/builder, Royalton Homes, Inc., is planning to occupy one quarter of the building with its own offices, and lease the remaining three units.
It is the first structure Royalton has ever built using ICFs. Vice President Sam Chaaya and his partners selected the EPICF primarily for its high R-value and the energy efficiency it would confer on the building. (Temperatures in Collingwood went below -22º C (-8º F) two of the past three winters, and rose to over 35º C (95º F) this summer.) Royalton was also attracted by the durability of a concrete structure, which Chaaya personally believes could last more than 100 years.
The basement foundation was built with conventional 6.25 cm (2.5 inch) ICF, switching to EPICF for the two above-grade floors. Chaaya’s assessment is that the new, wider blocks are easier to build with than the conventional ones, and it speeded up construction on the upper floors. According to Chaaya, mating between block-tops and bottoms is more precise with the 8.25 cm (3.25 inch) EPICF due to the wider mating surface, so it is easier to keep wall alignment straight, resulting in faster construction.
He also observed that the EPICF blocks seem stronger than conventional ones due to the increased EPS thickness. His crew almost suffered a blow-out in the conventional block on the basement level. They had cut a section out of the interior side of a block to allow for a column, and the missing web weakened the integrity of the block on the exterior side. The exterior EPS panel bulged outwards, but they were able to brace it from the outside before it actually ruptured or leaked concrete.
By contrast, he has seen no such problems with the EPICF blocks, and doubts they are vulnerable to it. Chaaya also noted that the corners of the new system seem stronger than in conventional blocks, and the fact that the legs of the angle are longer saves a small amount of time.
Royalton initially expected construction cost to be about 30% higher than wood-frame construction, but felt that the energy savings would be worth the investment. Once construction got underway, they found that the actual cost difference would be considerably less, closer to 10%.
Based on this debut experience with ICF construction, Chaaya is impressed to the point of action. He has several upcoming residential projects that he plans to build using EPICFs.
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