Open Cell Spray Foam Insulation in Commercial Buildings
Historical Center of Bastogne World War II Memorial
Photos courtesy of ICYNENE, Inc.
Opened in 1976, the Historical Center of Bastogne is a World War II memorial that recognizes the support from United States troops during the Battle of Ardennes in 1944-45. Close to the Luxembourg border, the Historical Center is in the Belgian city of Bastogne and was built as a joint effort between the United States and Belgium commemorating the infamous Battle of Ardennes, also known as the Battle of the Bulge, in 1944/45. Together with the nearby Memorial du Mardasson, the Historical Center of Bastogne celebrates the support from U.S. troops and remembers the numerous casualties sustained in the battle. The center showcases weapons and uniforms, and depicts stories from the battle and World War II, attracting thousands of visitors from across the globe annually.
In spring of 2013, the center re-opened as the Bastogne War Museum beside the Memorial du Mardasson providing visitors with a new space to learn about the battles within the region. The City of Bastogne hired local Wallonian construction company Wust Corporation, part of the BESIX Group, to lead the construction of the new museum space and restore the star-shaped historical center.
The Challenge
Initially, the project only included the construction of two new buildings designed to complement the existing building. The Historical Center of Bastogne, a large wooden framed structure in the shape of an American star with a slate roof, was considered well insulated by officials. However, when drilling into the walls of the star-shaped structure to connect the new and existing buildings together, contractors discovered serious problems due to the poor insulation that had been previously installed. Their first discovery was that there was no vapor barrier or air seal. The insulation that had been installed was a traditional fiberglass material. Furthermore, the slate roof was not breathable since the underside of the roof had been covered in PVC plastic.
The climate in the Ardennes region of Belgium, France and Luxembourg fluctuates with humid summers and temperatures often plummeting to -20°C (-4°F) in winter. As a result of this climate interacting with the center's construction, the contractors discovered abundant condensation, mold as well as rot at the bottom of the wooden frame structure. The rotting frame would lead to a stability problem, a problem that officials were not expecting and knew they had to address quickly. City officials, designers, and contractors sought to eliminate these concerns by finding a solution that did not require the roof to be completely renovated since officials had stipulated that the roof would not be replaced.
The Solution
The construction contractor and insulation sub-contractor, Delhez Systemes met with officials from the City of Bastogne, engineers and architects to ensure that every discovered problem was addressed. The team also had to ensure they could sufficiently address the non-breathable roof. The team at Delhez had studied the problem areas with a variety of scenarios and proposed solutions. Open-cell, light density spray foam insulation was chosen as the ideal solution for the historical center. It was recognized that this soft, flexible material maintains an air seal throughout the seasonal changes. As a vapor permeable material, it also supports bidirectional drying of assemblies. The lightweight, air-tight and healthy insulation solution proved to be ideal for the historical center and was successfully applied. The application took about four days and was installed throughout the building, with some areas reaching 20 meters high.
One month after the application, lightning struck the historical center during a thunderstorm, causing the center's wooden frame to ignite. The fire burned the wooden frame but was slowed down by the airtight spray foam insulation, which does not propagate flames, thereby limiting the damage caused to the building and to its frame. The spray foam insulation managed to slow down the fire enough to be able to keep all of the physical properties of the building intact. Firefighters, as well as officials and engineers, were pleasantly surprised at the insulation's fire dampening qualities. Once the damage was repaired by the contractor, insulation sub-contractors re-sprayed the fire damaged area with new insulation returning the damaged areas to like new condition.
The Result
Following application of the low-density spray foam insulation, the historical center is now a well-insulated and air-tight building. Right-sized mechanical ventilation systems were installed to ensure that visitors to the center, as well as employees, are comfortable throughout the seasons. The probability of condensation leading to mold and rot is now minimized, ensuring that the historical center's structure and frame remain sound over the long term. City officials and Wust engineers were not only surprised by the spray foam's qualities following the fire but were impressed with the ease of the insulation's application. The professionalism, cleanliness and knowledge from insulation subcontractor were also acknowledged by city officials. Construction was able to continue at the site with the opening of the new Bastogne War Museum occurring in spring 2013 with more than 400 artifacts and interactive exhibitions.
Enhancing Building Durability with Open Cell Insulation
Durability of a construction assembly and a building relies on the integrity of materials remaining intact during the full service life of the building. The biggest common threat to that integrity is damage from moisture seeping into enclosed cavities and causing damage to materials or structural components of a system. According to ASHRAE, moisture damage contributes to 90 percent of all building and building material failures. Moisture issues in commercial buildings contribute to the corrosion of metal components (i.e. ducts, framing) and the general degradation of other building materials (gypsum sheathing, ceiling tiles, wood products, etc.). Unwanted moisture in building systems can also create the growth of mold and poor indoor air quality thus affecting the health of the occupants.
The predominant source of this unwanted damage causing moisture is from air leakage which carries that moisture with it through openings or irregularities into wall and roof assemblies. In this case, low-density open cell spray foam insulation can play multiple roles in preventing moisture laden air from penetrating into a building assembly. By creating an effective air seal to begin with, the potential for air leakage and moisture penetration is reduced notably. If any moisture does get through, the insulation itself helps to prevent it from condensing by keeping the moisture laden air from meeting cold exterior surfaces.
The open cell make-up of the insulation helps manage any bulk water present by allowing it to drain away and enhancing the ability of the assembly to dry out. In roof assemblies, this quality can make it easier to spot the source of leaks and thereby permit any roof repairs to be made more easily. Even after minor wetting, most low-density open cell spray foam products are not a food source for mold so they will not contribute to that problem or the associated indoor environmental quality issues associated with it. Overall, creating an air barrier with low-density open cell spray foam insulation can pay off with a longer life of commercial building assemblies, can help prevent the need for costly repairs and can avoid lost operational time.
Separate from air leakage, the other means for vapor to enter an assembly is direct diffusion through materials. This raises the question of whether or not a vapor retarder is needed to stop that diffusion when open cell spray foam insulation is used. In the warmer U.S. climate zones 1 through 4, an interior vapor retarder is not required by code, with the exception of places where high interior relative humidity is present such as indoor swimming pools. In other climate zones or locations where a separate vapor retarder is required, it can often be achieved by using vapor retarder paint which creates a full and continuous barrier to moisture diffusion. Some approved vapor retarders can be painted directly onto the insulation in cases where the insulation is either exposed or the finished covering is not going to be painted. The more common approach is to use any one of a wide range of vapor retarder coatings available for painting on the sheathing or gypsum board which the open cell insulation is covered with. This vapor retardant paint then keeps any moisture from penetrating into the gypsum board or into the rest of the assembly.
Properly designed and installed then, roof and wall assemblies in commercial buildings that use open cell spray foam insulation and appropriate vapor retarders will notably reduce the chance of moisture damage and contribute to the overall durability and long term integrity of the building.
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