Posted on July 08, 2021
Soaring lumber prices drive new interest in insulated concrete form (ICF) construction. architects and designers take a closer look at ICFs for residential construction. They specify ICFs for below-grade foundations, above-grade exterior walls and interior walls.
Lumber Price Volatility
Lumber has long been viewed as a cheap and plentiful building material. Today's high prices erase much of the price advantage. In early 2020, lumber was about $500 per thousand board feet. Since then, prices have increased to double or triple that. On May 7, 2021, the price per thousand board feet closed at $1,686. Markets Insider graphs real-time lumber prices. It highlights lumber’s day-to-day price volatility.
Analysts see multiple reasons for high lumber prices:
Reduced production due to the pandemic
Impact of tariffs on Canadian lumber
Low mortgage interest rates accelerating demand for new homes
According to the National Association of Homebuilders (NAHB), lumber prices add as much as $36,000 to the cost of an average-sized new home. Someone has to bear the burden of these sudden increases, and it’s usually the home buyer. New home buyers benefit from low mortgage interest rates. They sacrifice those financial gains by paying high prices for traditional wood-framed homes.
When lumber prices soar, new home buyers have a choice. They can get something for the extra money or not. Home buyers who opt for ICF construction invest in long-term value. ICF homes often increase comfort, energy savings and resale values compared to wood-framed ones.
ICF Homes: More Competitive Than Ever
ICFs offer both price stability and supply chain consistency. For example, a Logix graph shows how component prices tend to follow the rate of inflation.
Advocates of insulated concrete forms often cite life cycle costs as a key advantage. When lumber prices are high, ICF construction may deliver lower upfront costs as well. For example, Amvic estimates that pre-pandemic ICF walls cost one to four dollars more per square foot than stick framing. With the increase in lumber prices, the ICF manufacturer asserts that “those costs now approach parity.”
It is also important to consider that energy-efficient ICF homes often work with lower-capacity HVAC systems. Reductions in the HVAC equipment required save another $0.75 square foot.
A tree left alone in the woods is carbon neutral. It absorbs carbon for growth, although absorption rates decline with age. As it dies and decays, it releases its carbon back into the atmosphere. Harvested lumber keeps that carbon out of the atmosphere for decades, but not necessarily forever.
By contrast, installers stack, brace and fill ICF forms with concrete. SCMs reduce the amount of cement needed in concrete. Rebar is often fabricated from up to 99 percent recycled steel. Microbar reduces the use of traditional rebar at some projects. Finally, recycling ICF walls completes the cradle-to-grave sustainability cycle.
With ICF construction, energy savings accrue year after year. One study compared an ICF building to 1) a traditional wood-frame structure, and 2) a wood-frame building built to higher standards. Assuming a 100-year lifespan, the ICF building’s life cycle energy use was far less. The sustainability gap decreases between wood and concrete because ICFs simply last longer.
The International Center for Sustainable Development (ICSD) issued a report discussing sustainability issues. It is titled, “Emission Omissions: Carbon Accounting Gaps in the Built Environment.” Among other things, the report takes a comprehensive look at ICF vs. wood construction. It says, “Building efficiency and longevity should be the priority for decarbonizing the built environment.” ICFs excel at delivering both.
The report also asserts that, “improvements in energy efficiency and developing new low- or net-zero-energy buildings offer the highest mitigation potential."
The report's authors call for policies that promote longevity, durability and service efficiency. They also call for "rehabilitation and remodeling to extend service life.” Collectively, such efforts reduce GHG emissions by notable margins.
More ICF Benefits
Finally, ICF homes deliver other key benefits. Four-hour fire ratings are common. Interior ICF walls deliver superior fire-resistance throughout the home. Flame-retardant additives in the EPS foam complement the inherent fire resistance of concrete.
Sound attenuation is another benefit. ICF exterior walls reduce the transmission of street noise. ICF interior walls reduce sound transmission from room to room.
ASHRAE Energy Standard 90.1 called for continuous insulation in 2007. The standard is now common in today’s building codes. ICFs address the problem of thermal bridging. Continuous insulation is inherent in ICF wall construction. By contrast, continuous insulation in wood-framed homes requires extra steps. Wood-frame construction demands add-on vapor barriers, while ICF walls do not.
At resale, a real estate agent can point to key advantages of an ICF home. These include longevity, energy savings, fire resistance and reduced sound transmission. Depending on the market at the time, an ICF home owner may see higher offers and a quicker sale.
The Future of ICF vs. Wood-Framed Homes
Many wonder whether lumber prices are spiking or plateauing at a high level. Some analysts suggest that lumber prices may fall by late 2022. However, that is still more than a year away. In the meantime, buyers are clamoring for homes. Time and again, in-demand single-family homes make the news. They often garner cash offers, frequently above the asking price.
The Pennsylvania Aggregates and Concrete Association (PACA) brings news of current industry developments to its members and to the general public. For further assistance, please contact the team at PACA today.