The sandwich wall panel process provides a low cost, thermally efficient and decorative alternative to traditional brick and mortar construction. An insulated sandwich wall panel consists of two wythes (a continuous layer of concrete) separated by an insulated void. Typical panel thickness ranges from 8 to 12 inches depending on the thermal R-value desired. Stonecast’s two wythes of the interior and exterior concrete layers surround high R-value insulating foam and are held together with steel or composite fiberglass connectors.
Although there are many different techniques in the industry to hold the sandwich panel layers together, Stonecast utilizes the proven HK Composites system utilizing the fiber-reinforced connectors. Concrete sandwich panels historically held together with steel trusses are inferior to those held together with composite fiberglass connectors. This is because the steel creates a thermal bridge in the wall, significantly reducing the insulation performance and reducing the ability of the building to utilize its thermal mass for energy efficiency.
There is also the risk that because steel does not have the same expansion coefficient as that of concrete, as the wall heats and cools, the steel will expand and contract at a different rate to the concrete, which can cause cracking and spalling. Fiber-reinforced connectors such as the HK composites system that are specially developed to be compatible with concrete significantly reduce this problem.
Sandwich wall precast concrete panels can be used on most every type of building. Depending upon building function and layout, the interior and exterior layers of concrete can be easily designed to handle both the structural requirements for strength and safety, as well as the aesthetic and sound attenuation qualities the owner desires. Speed of construction, durability of finished structure, and energy-efficiency are all hallmarks of a building that utilizes a precast insulated sandwich panel.
A general example of how a standard sandwich panel is constructed is shown below. Stonecast utilizes the proven HK composites system to create insulated sandwich panels. For more information on the HK composites system, click here, https://hkties.com/.