| The use of ICF construction and SIP walls is strongly | | | | materials for ICF are more expensive; namely the |
| debated in the sustainable construction industry. Both | | | | concrete per square foot. Also, a prefabricated |
| wall systems are very energy efficient and create | | | | product is not being delivered to the site so the labor |
| super insulated walls that meet LEED accredited | | | | cost is more by the time the ICF walls are installed. |
| standards developed by the U.S. Green Building | | | | The overall price for materials and installation of an |
| Council. Both products will construct such an airtight | | | | ICF wall system can be gauged at about 30% higher |
| space that heat recovery ventilation systems are | | | | than traditional poured walls. |
| needed to produce airflow. These systems must be | | | | In comparison, an ICF wall needs to be thicker than a |
| carefully installed to eliminate thermal breaks in the | | | | SIP wall in order to achieve equal R-value. Thicker |
| super insulated space. Traditional stick framing can | | | | walls mean more material that also contributes to a |
| claim up to R-20 walls. This, however, only considers | | | | higher cost compared to SIP construction. |
| the highest rated component in the wall, the | | | | Local Availability |
| insulation. Other lumber and utility members in the wall | | | | Local availability can contribute in variance of price, |
| contribute to thermal bridging which is a main factor | | | | and level of green construction. Not all contractors |
| in heat gain and loss. Both ICF and SIP wall sections | | | | build with SIPs or ICFs, but as this construction, and |
| contain solid insulation material that will effectively | | | | production becomes more popular the price for both |
| eliminate conduction and convection in the building. In | | | | will come down. Contractors and manufacturers are |
| addition to energy efficiency, one of the greatest | | | | most abundant in the Midwest and Southwest of the |
| benefits that both systems share is the ability to | | | | United States, making these regions cheapest to build |
| construct quickly and accurately. | | | | using SIPs and ICFs. Investigate which contractor and |
| It is evident that both of these wall systems provide | | | | manufacturer (SIP or ICF) is more local; this makes |
| sustainable construction, but when it comes time to | | | | the project more sustainable and will most likely offer |
| build, which one should you use? As most building | | | | lower prices. However, beware of inexperienced |
| decisions eventually do, it all comes down to cost. | | | | contractors because it is a new building practice. In |
| When analyzing the cost of these wall systems, it is | | | | accordance, more experienced contractors typically |
| important to understand the price varies according to | | | | can charge less. |
| each design, availability, and installation. This topic is | | | | Return |
| debated by company representatives all over the | | | | Sustainable building is encouraged by the return |
| internet. I am not a salesman for SIPs or ICFs, so | | | | investment. An airtight, superinsulated home created |
| consider this a fair analysis. | | | | by either of these wall systems allows for lower |
| Cost per Square Foot? | | | | operational costs due to monthly utility bills. In |
| It is very difficult to provide an estimation of cost | | | | addition, the HVAC equipment required to heat and |
| based on square footage. Many factors are involved | | | | cool this superinsulated house does not have to be |
| that can only be accounted for in the exact | | | | as powerful, saving you hundreds or even thousands |
| specifications of the architect's plans. A general cost | | | | of dollars on initial HVAC costs. While these savings |
| for square foot of gross wall area may be compelling | | | | are equal between the two systems, other returns |
| as a feasibility estimate in theory, but more factors | | | | are not. Homeowner insurance savings are between |
| must be involved according to design to make an | | | | 15-25% for ICF construction due to fire protection |
| appropriate estimate. One can research and find a | | | | ratings and disaster resistance. However, no serious |
| wide range of cost estimates by vendors and | | | | gains in equity are made for when it comes time to |
| builders. The average of these values should not be | | | | sell. At this time, tax benefits do not exist for building |
| considered to estimate cost since they are from | | | | LEED projects, but it is hopeful that in the future |
| people trying to sell you a product. Instead, I have | | | | they will. If considering a LEED scorecard in your |
| analyzed the trends of these values to find that the | | | | decision, SIPs will score higher because it is a pre-built |
| difference of these prices suggest that SIP | | | | panel assembly. |
| construction costs 5-10% less than ICF construction | | | | Conclusion |
| per square foot. | | | | SIP construction is generally considered less |
| Design | | | | expensive when deciding which sustainable building |
| Window and door placement and shape must be | | | | envelope to use. However, each project varies in |
| accounted for when the fabricators make cuts in | | | | price of each according to design specifications. |
| panels or forms. Waste is produced in this process | | | | Design can be optimized to standard dimensions of |
| while labor is involved driving the cost up. In some | | | | each wall system to encourage lower costs. |
| cases, the cost can be optimized in the design of the | | | | Whichever product is manufactured closer to the site |
| home by strategically dimensioning the home including | | | | is more sustainable and will cost less in comparison to |
| window sizes and wall lengths according to | | | | each average cost. Considering this the cost |
| dimensions suggested by multiples of panel or form | | | | difference between the two may increase or |
| sizes. | | | | decrease. ICFs may cost more but they generally |
| Many manufacturers consider structural live and dead | | | | offer more return in terms of insurance deductions. |
| load analysis of the design when estimating cost. This | | | | Overall, it is important to investigate all of these |
| analysis of the plans will more accurately explain what | | | | aspects when deciding which will be less expensive. |
| thickness is needed where, and how much. The | | | | |