Roof and foundation insulation can prevent energy loss

New findings indicate that integrating design solutions at both the roof and foundation levels of buildings can lead to operational energy savings, effectively offsetting the embodied energy of the insulation itself. This discovery is significant, as structural engineers aim to minimize energy losses, reduce costs, decrease environmental impacts, and protect public health. It is proposed that incorporating insulating or low thermal transfer materials within load paths can enhance a building’s energy efficiency and air quality.

To maximize building performance, effective insulation must be applied to the foundation and base levels, even when space for insulation is limited. Several solutions can address these challenges, such as Frost-Protected Shallow Foundations (FPSFs). In addition to providing insulation, FPSFs help reduce excavation needs and the use of reinforced concrete, ultimately lowering embodied carbon and improving cost-effectiveness.

Furthermore, engineers should consider the mechanical properties of insulation materials before selecting an appropriate insulation method. Environmental Product Declarations (EPDs) should also be reviewed. Traditionally, plastic foam derived from petroleum has been the most widely used insulation material, but it degrades over time due to moisture exposure. Soil can also serve as an insulating material, but it is compressible and exhibits pressure- and deformation-related limitations.

Alternative insulation options include mineral wool and stone-based products, which offer durability with an R-value of approximately 4.0 per inch. However, despite their effectiveness, these materials require high energy input for production, making them less sustainable. Mineral-based glass insulation, a low-embodied-carbon solution, enhances moisture resistance and provides R-values ranging from 0.9 to 1.7 per inch, reducing environmental impact.

Another method to prevent energy loss is column-bearing blocks, which provide both structural support and thermal insulation. These blocks serve as effective thermal breaks for roof penetrations, with compressive strengths ranging from 300 to over 2,000 psi at 2% deformation and R-values between 1.5 and 2.5 per inch.

Due to evolving energy codes, insulation placement is now mandatory around buildings, whether installed on the interior, exterior, or within foundation walls. When installed on the exterior, insulation typically extends up to the façade, forming a continuous thermal envelope. However, placing insulation inside a basement or foundation wall requires additional structural design elements to transition insulation beneath exterior walls.

Insulation transition challenges can be addressed using autoclaved aerated concrete (AAC), hemp-based blocks, graphite polystyrene (GPS), and treated wood. These materials ensure proper alignment with the exterior wall envelope while offering durability. Additionally, middle-layer insulation uses low-conductance ties to secure foam insulation panels, similar to concrete sandwich wall panels.

In conclusion, structural engineers play a critical role in advancing energy-efficient design methods. Their expertise can drive improvements in energy codes, enhance building durability, and promote sustainability. Through informed material selection and product specification, engineers can achieve optimized structural designs that balance operational energy efficiency with embodied energy impacts.