Energy consumption is directly related to the costs to own, rent and operate residential and commercial buildings. Finding ways to reduce energy consumption in existing and newly constructed buildings has been a target by governing agencies, owners, tenants and design professionals. There is an upfront cost to designing for roofing systems that are efficient and then purchasing and installing those systems as compared to lesser comparable options that do not yield the same efficiencies.
One innovative solution that has been on the market for about a decade but has grown in popularity is the use of vacuum insulated panels (VIPs) for roofing. These panels are different in the market compared to other insulation for their high R-value. The R-value of insulation is a value that is used to measure how well a specific type of insulation can resist heat flow. In this case it would be to support the most efficient way to retain heat or prevent heat from entering a building.
These panels provide excellent thermal insulation and can significantly enhance the energy efficiency of a building with less material. In this article, we will explore the benefits of vacuum insulated panels for roofing, the installation process, the cost analysis, as well as the challenges and limitations associated with this technology.
Introduction to Vacuum Insulated Panels
In recent years, vacuum insulated panels (VIPs) have emerged as a promising solution for improving the energy efficiency of buildings and working within existing parameters such as flashing heights. Some are touted as R-50 in 1 ¼”, other technologies and similar panel insulation have R-values closer to 30 per inch, but when compared to their traditional counterparts they all have one thing in common: significantly higher thermal R-values, in a fraction of the space. The benefit of having significantly more R-value and significantly less material mass to the insulation product can be quantified by reviewing the limitations of any building structure and all the components that are interfacing with the building envelope. The factors of R-value, which have always been directly correlated with insulation thickness, cause limitations because the thickness of roofing systems impact so many other building elements. The cost to install high R-value roofs with typical R-value insulation must integrate the following systems and components: mechanical, electrical and plumbing (MEP), heating, ventilation and air conditioning (HVAC), exterior walls, doorways, roof heights, roof top equipment, roof decks, parapet walls, drain systems, etc. The International Building Code, and state and local codes have been changing for decades to include higher efficiencies in new construction as well as retrofits and replacements in existing buildings. These changes are systemic to a broader impact on building design and construction practices in an effort to minimize our carbon footprint.
If you are unfamiliar with the basic technology, VIPs are essentially sealed boards that achieve higher R-values due to the absence of air within the film. There are specifics around what type of core they have or what they are sealed with, but they often end up looking a bit like a pop-tarts® wrapper.
Their exceptional thermal performance, combined with their slim profile, make them an attractive choice for roofing applications, particularly roof replacements. With their ability to significantly reduce heat transfer, VIPs can help keep buildings cooler in the summer and warmer in the winter, leading to reduced energy consumption.
Benefits & Drawbacks of Vacuum Insulated Panels for Roofing
One of the key advantages of VIPs is their slim profile. Unlike traditional insulation materials, such as polyisocyanurate, extruded polystyrene (XPS) or even closed cell spray foam, which can be bulky and take up valuable space, or require costly and disruptive access to the interior; VIPs are incredibly thin, allowing for more design flexibility in terms of retrofit applications. Take for example a typical existing building in the greater Boston area. Perhaps there is an existing roof mounted safety rail, and the door thresholds and related existing roof flashings are currently 8” above the finished roof surface. Where there are roof leaks, it is typical for roof penetrations and the existing insulation to be saturated with moisture, requiring the roof system to be replaced. In a traditional scenario, the existing insulation is removed (let’s call it 2”) exposing the structural deck. The energy code now requires R-33 to be achieved. This would require almost 6” of polyisocyanurate insulation; the through wall flashings, drains, pipe vents and any equipment curbs would have to be raised at least 4”. Additionally the roof safety rail might need to be modified and/or replaced to meet code requirements. Those modifications are often as expensive, if not more so, than the actual roof replacement!
In that same scenario, the R-33 value can be easily achieved by utilizing a VIP and the flashing heights or railings would not have to be modified.
Another key advantage with VIPs is the increased insulation value leading to deceased energy consumption. In a study by the General Services Administration (GSA) from 2014, they found that energy savings of up to 10% can be achieved. Unfortunately, that energy savings is only that high on single-story buildings. The savings diminish on mid- and high-rise structures due to the relative smaller area of the roof in proportional ratio to the façade.
An important consideration when choosing to utilize VIPs versus traditional insulation methods are the modifications necessary to make existing flashing heights work with those traditional systems. If those modifications are cost prohibitive, that tends to be the perfect case to consider VIPs. While VIPs offer excellent thermal performance, they can be more expensive upfront compared to traditional insulation materials. It is crucial to weigh the long-term energy savings against the initial investment to better determine the cost-effectiveness of VIPs for your specific project. Consulting with professionals in the building envelope field can provide valuable insights and help you the Owner make an informed decision.
The major drawbacks for VIPs revolve around material cost and the product fragility. While they are not as fragile as they once were, they still cannot be punctured, otherwise they lose almost all insulating properties. The handling of the material is paramount to the integrity of the product. This can make them difficult to utilize if the roof has a lot of penetrations since those areas need to be infilled with polyisocyanurate insulation. The other part of the “no puncture” stipulation that affects VIPs is the fact that they cannot be mechanically fastened. This means that in certain high wind uplift environments, they cannot be used at all. If the fictional roof example from before had wind loads that did not allow for fully adhered roof systems to work, the Owner would have to unfortunately foot the bill for raising all of the flashings, thresholds, railings, door heights, etc. As for cost, when compared to the material board of polyisocyanurate insulation, VIPs are significantly more expensive, but when prospective customers bring this up as an argument, they almost never factor in the savings, such as raising those flashings.
If you are considering upgrading your roofing system or looking for ways to reduce your energy consumption, vacuum insulated panels may be a valuable investment. Their ability to provide superior thermal insulation, combined with their slim profile and durability, make them an appealing option for both residential and commercial applications. By reducing heat transfer and improving energy efficiency, VIPs can contribute to a more comfortable living or working environment. Consult with professionals in the field to assess the suitability of VIPs for your specific needs and make an informed decision that can lead to long-term energy savings and a more sustainable future.
Vacuum insulated panels are a game-changer in some applications when it comes to roofing insulation. Their exceptional thermal performance, slim and lightweight design, and energy-saving benefits make them an ideal choice for retrofitting projects.
Installation Process of Vacuum Insulated panels Roofing
The installation of vacuum insulated panels requires careful planning and expertise. The process begins by assessing the existing roof structure and determining the appropriate thickness and size of the panels. This crucial step ensures that the panels will fit seamlessly into the roofing system, maximizing their thermal performance.
Once the panels are manufactured to the desired specifications for R-value, size and quantity, they are delivered to the site and installed by trained roofing professionals. The roofers meticulously handle the panels to prevent damage during transportation and installation. Their expertise ensures that the panels are installed correctly, guaranteeing optimal energy efficiency and long-lasting performance. Lead times for manufacturing and delivery can vary, but as always, it’s best to get a schedule from the Contractor early in the process.
First, the existing roof surface is prepared by cleaning and ensuring it is free from dust and debris. Any imperfections or irregularities in the roof surface are addressed to provide a solid substrate for the installation of the VIPs. Then, a layer of adhesive is applied to the roof surface. This adhesive is specifically designed to bond the vacuum insulated panels securely to the roof, providing a strong and durable installation. The adhesive is carefully applied, ensuring an even distribution across the entire roof surface. Next, the VIPs are carefully placed and secured in the designated areas. Once the panels are installed, the remainder of the roof system, including cover board, membrane and flashings can be installed as typical with low slope roof systems.
At Duffy Engineering, the intent for any product and system recommendation is that it will be well suited for the structure and will meet and exceed industry standards. In this case, the VIPs serve as an innovative product to help bridge the need that older existing buildings have to be changed for code compliance and improved efficiencies such as better R-value.
