Long-term energy efficiency begins in the wall

by brittney_cutler | April 22, 2022 3:46 pm

[1]

By Todd Gluski

Fluffy (and potentially messy) flash-and-batt insulation is primarily what still comes to mind when the general population thinks about ‘insulation’ for a building. This form of insulation is still used extensively, but it has been surpassed by higher-performing products which have an added benefit of meeting requirements for other wall components as well.

With innovations in material technology advancing how professionals think about—and ultimately construct—exterior walls, new methods of insulation have moved to the forefront of the conversation when it comes to performance over the long term.

Insulation needs to be seen as an investment capable of providing superior thermal performance while adding long-term value to a structure. Structural continuous insulation materials are a viable and industry-leading solution. This insulation type shields commercial buildings from outside elements such as heat, cold, air, and moisture. In addition, some variations of this product can include a structural component (equivalent to using structural sheathing) which effectively enhances lateral shear properties of an entire wall system. Speedier installation, expedited project timelines, and cost efficiency are all benefits of structural continuous insulation, with the added advantage of enhanced energy efficiency for the whole building and protection against water and moisture.

Selecting the right insulation for enhanced energy efficiency

Continuous insulation is vital to a wall’s overall performance and serves as the last line of defense when it comes to keeping heat inside (or outside) of a structure. For large-scale commercial buildings, its role is even more pivotal. In essence, as heat is transferred through studs, a barrier must be in place to reduce energy loss. If insulation is not installed continuously across the building envelope, a structure is not living up to its full potential in terms of thermal performance.

Every built structure must combat internal temperature fluctuations, and certain factors cannot be controlled, such as outside temperatures which vary from season to season. For building owners of every kind, maintaining a comfortable interior temperature is a perpetual challenge requiring constant adjustment to the thermostat for the HVAC system, or opening and closing the windows to suit owner and occupant preferences for comfortable internal temperatures. Choosing continuous insulation during the construction phase of a commercial project can make a discernible difference. This choice can also positively impact code compliance and can lead to greater efficiencies when it comes to project completion for building crews.

Choosing continuous insulation can pay dividends for building owners and occupants by keeping buildings cool in the summer and warm in the winter. In addition, because continuous insulation keeps interiors at the right temperature for longer, energy consumption is reduced. This carbon footprint reduction in a commercial or multi-family building can go a long way in supporting a healthy built environment and saving building owners money on monthly energy bills.

The key considerations are thermal bridging and moisture buildup. Continuous insulation products are manufactured specifically to overcome these challenges.

Thermal bridging occurs when heat is transferred through uninsulated material such as a wall stud. This occurs in wood and steel frame construction, but more so in steel because it is much more conductive than wood.

Exterior continuous insulation prevents thermal bridging (and therefore thermal loss) by providing an uninterrupted barrier outside of the studs. This allows builders to deliver high R-values even in 2×4 construction, which results in a thinner wall that still delivers on long-term performance. For the owner, this curbs the overall energy needs of the building.

[2]

Within the wall, location matters

Thermal loss can negatively impact the comfort of interior environments as well as energy consumption, but moisture penetration is potentially an even greater concern, as it threatens permanent damage to the skeleton of a structure. If it is a multi-family residential building or a high-use office building, repairs for moisture and water damage could lead to interrupted living arrangements and work schedules, as well as headaches for owners and building occupants alike.

Continuous insulation, however, is installed outboard of the studs, which moves the dew point from inside the wall cavity to the outer side of the sheathing. The location of the material is pivotal. As a result, the opportunity for condensation to form within the wall cavity is dramatically reduced. This form of insulation has often been described as a ‘blanket’ around a structure. Logically, it makes sense to install the material designed to heatproof a building around its exterior, not on the interior where thermal energy can already begin moving through the studs.

As added protection, continuous insulation products can be made with weather-resistive barriers applied directly to the surfaces of the product. Combined with the position of continuous insulation on the wall, this significantly decreases the risk of mold growth and defends against structural rot. By nature of being continuous, when installed properly with high-performance seam tape, this type of insulation provides a weathertight barrier enhancing long-term building envelope performance.

Strengthened by integration

Fully integrated continuous insulation serves as a high-performance product combining multiple wall layers into a single, lightweight, easy-to-install option. However, some continuous insulation products still require an additional layer of structural sheathing to complete the wall system. Structural sheathing, of course, is a necessary wall component to allow for the installation of exterior finishing materials like brick or siding. There are excellent alternative options combining these two key wall components—structural sheathing and continuous insulation—into a single solution capable of providing time and cost savings to builders.

This is especially true for crews charged with constructing larger-scale buildings such as apartment buildings, offices, restaurants, churches, and other commercial structures, and even residential homes. The burden of installations for big buildings requires a great deal of time for crews. When a manufacturer can integrate many different components into one product, the number of passes around the structure is reduced. Traditionally, sheathing, insulation, and then the control layers protecting a structure from moisture and air penetration all require separate installations. These represent at least four trips around a building. Consolidating each of those layers into one product, allows crews to move on to the next phase of the project much sooner.

[3]

Some manufacturers have developed four-in-one product solutions that combine all of the necessary components that need to be installed behind the builder’s cladding of choice.

These four-in-one insulation materials tackle four key elements necessary for high-performing exterior walls:

∞ Structural sheathing

∞ Continuous insulation

∞ Air barrier

∞ Water-resistive barrier

Integrated structural continuous insulation products such as these ease the installation burden for installers. Plus, many of these products remain lightweight and can be lifted by a single worker. This allows them to complete construction of the building envelope in much less time and with less effort.

Doing the math on R-values

Building code requirements are evolving, which forces builders to choose products able meet a particular standard. Climate change and energy conservation continue to influence this paradigm, and in the United States and elsewhere, more jurisdictions are requiring specific R-values[4] for residential and commercial structures.

However, there are a variety of ways to meet the R-value minimum for an exterior wall. Depending on thickness, integrated structural continuous insulation products can deliver R-values of 7.5 up to 13 when installed. This is before cavity insulation or other means of insulating a building are even considered.

According to the International Energy Conservation Code (IECC), R-values for wood-framed structures in climate zone one require a value of R-20. This means continuous insulation with a value of R-13 gets builders more than halfway to the desired final sum for a large portion of new builds throughout the United States, including the northernmost states. Of course, this number changes depending on the climate zone, but continuous insulation is a viable option to help builders solve the R-value equation, regardless of location.

Installation of this product type is continuous across all structural members by nature of its design. Panels of insulation are secured to the exterior side of the studs, and then high-performance tape is applied to the seams between each panel. This delivers comprehensive coverage behind the cladding of choice, whether that is siding, brick, stone, or another exterior finishing material. This seam tape will also allow for the natural expansion and contraction cycles which occur throughout a building’s lifespan as the seasons change.

Once the panels are installed and seam tape is applied at the gaps, the insulation is completely continuous. Therefore, when calculating the R-value of a home, an additional R-2 is factored into the equation. Builders who opt for R-13 continuous insulation panels (plus the additional R-2 for being installed continuously) can achieve a value of R-15 before adding in supplementary flash-and-batt or spray foam insulation on the interior side of the wall.

Tangible savings: Labor, time, and costs

Performance-wise, structural continuous insulation is the optimal solution when assembling and constructing the exterior wall of any building. An added benefit is this solution also delivers time and cost savings on the jobsite.

Structural continuous insulation is typically one-third the weight of traditional oriented strand board (OSB). This allows for more efficient use of labor, requiring less hands on deck. A single worker can efficiently prep, mount, nail, and tape a board of continuous insulation without any special tools or additional help.

In addition to structural and insulating components, these products feature an integrated water-resistive barrier as well as an air barrier. In typical construction, OSB or another sheathing product must be installed first, then a weather-resistive barrier, and finally a layer of continuous insulation. Combining each layer into a single product dramatically reduces the amount of time crews need to spend on the jobsite, saving both time and money for the installers and the owners.

Insulation of the future

The construction process can be a balancing act for managers and their crews. It requires paying mind to using the right high-performance materials, meeting building codes for a particular climate zone, and working efficiently to finish the job within the established timeline and on budget. Architects and contractors must simultaneously deliver on the mandate from the eventual owners and occupants of a building—a safe, comfortable structure built to last.

Regarding performance, integrated structural continuous insulation provides a solid defense against hot/cold air transfer, moisture accumulation, mold growth, and structural rot. It is a long-term solution for an incredibly important phase of the construction process, and a key consideration able to answer the call for code compliance mandates.

When factoring in the efficiencies and potential cost savings on a job site, continuous insulation can be a gamechanger for construction projects of all types.

Author

Todd Gluski is the director of marketing for OX Engineered Products and has been with the organization for four years. Prior to his time with OX, Gluski served in a variety of marketing and brand management roles at leading building materials manufacturers across the United States. Gluski can be reached at tgluski@oxep.com.

Source URL: https://www.constructionspecifier.com/long-term-energy-efficiency-begins-in-the-wall/

---