What needs to be considered in a retrofit plan?
When deciding on enclosure-specific ECMs, consideration for thermal efficiency, durability, structural capacity, and constructability, among others, is necessary. Therefore, understanding the unique challenges of different building envelope retrofit options is critical to ensure appropriate solutions are applied. Let’s dive deeper into what that looks like.
Thermal efficiency: Existing buildings—whether commercial, institutional or residential—will typically have little to no insulation within the envelope, resulting in excess heat loss and increased energy consumption. More importantly, they usually have poorly installed or non-existent air barriers, making them very leaky and further increasing energy waste. The addition of insulation in exterior walls and roofs, combined with an appropriate air barrier system, is integral to improving building performance, reducing leaks, and creating more comfortable indoor environments. When it comes to the assembly’s thermal efficiency, we must consider the system's overall effective thermal performance, not merely the insulation layer's nominal thermal resistance. This means accounting for the thermal resistance of all applicable layers within the assembly and calculating reductions caused by thermal bridges.
Durability: One of the critical benefits of retrofitting buildings is that we can increase their lifespan. The added longevity and durability of an envelope and the energy savings they create are a way to justify the upfront costs. Considerations for an enclosure's durability include assessing the primary control layers, in particular those related to water and moisture management. It is critical to ensure that appropriate drainage and drying measures, and vapor diffusion control considerations are in place, as poorly designed retrofits may lead to unintended moisture damage.
Constructability: Simply put, a retrofit strategy's constructability relates to how simple it is to install and execute as well as the overall cost. In practice, each retrofit is unique, with no one approach to rule them all. Upgrading the building envelope can introduce different constructability challenges, depending on the building site and existing condition. The strategies applied will vary and cannot necessarily be used on all projects in the same manner. One common thread that does connect all projects, however, is people. Therefore, an effective strategy must also consider the impact on occupants.
Aesthetics: While very subjective, a building's aesthetics is often a primary concern for the architect, building owner and occupant. For existing buildings, the retrofit strategy may require the aesthetics of the façade to be altered or left untouched altogether. With more product options available for meeting retrofit goals, including ROCKWOOL stone wool batts and rigid insulation boards for both interior and exterior applications, increasingly a building’s aesthetic design doesn’t always have to be sacrificed for performance.
And though energy conservation is the primary driver for most large-scale retrofits today, there will be some other consistent criteria that should be considered in different types of commercial retrofits. Many are driven by the needs of the occupants. For example:
Office buildings: evidence shows that an office building’s indoor environmental quality (just like office ergonomics) will impact the long-term health and performance of employees; controlling noise with a proper acoustical insulation plan will protect their health and improve productivity.
Schools: student performance is also closely linked to the building’s indoor environment; receiving natural light during the day will help students sleep better at night, and while colder environments tend to improve concentration, once it exceeds a comfortable level, it will create a negative effect on student performance. Noise reduction is also beneficial for learning as well.
Hotels: a positive guest experience can rely as much on physical comfort and noise control—both in guest rooms as well as common areas—as it does on the building’s aesthetics; if design is an important criterion in a hotel’s retrofit, it need not be sacrificed for the sake of thermal or sound performance by the building envelope; new solutions in stone wool insulation products can satisfy both requirements.
