Insulated Panels are prefabricated building panels used in floors, walls, ceilings on buildings. Installing insulated panels for building constructions are aimed to ensure the energy efficiency, easy and fast installation and a decrease in operating costs. A structural insulated panel (SIP) is a composite building material; consisting of an insulating layer core sandwiched between two layers of metals.
Features of SIP
SIP’s are commonly made of the Oriental Strand Board (OSB) panels sandwiched around a foam core made of expanded polystyrene (EPS), extruded polystyrene (XPS) or rigid polyurethane foam. Other materials such as plywood, pressure-treated plywood for below-grade foundation walls, steel, aluminum, cement board such as Hardie Backer, and even exotic materials like stainless steel, fiber-reinforced plastic, and magnesium oxide can also be used in replacement of OSB. SIPs provide continuous air and vapor barrier as well as increased R-Value compared to traditional constructions. When labor cost, material waste and energy efficiency are considered SIPs are comparable to more conventional building methods.
The Idea of Structural Insulated Panels (SIPs) introduced The Forest Products Laboratory in Madison, Wisconsin in 1935. The laboratory developed a prototype panel consisted of framing members, plywood and hard board sheathing, and insulation. These initial panels were used to build test homes and tested after 30 years to reveal that the panels retain their initial strength. In 1952 Alden B. Dow created the first foam cores SIPs which were being mass produced in the 1960’s.
How to use SIP
The SIPs are designed to resist axial loads, shear loads and out of edge loads. These can be used for floors, walls, roofs etc… for the buildings. They have the ability to resist the bi-axial bending and lateral shear; so, they are very much suitable to be used as roofs and floors. The most widely used panel joint connections are the Surface spline and Block Spline. The Surface spline Joint Connection consists of the strip of OSB or plywood inserted into slots in the foam. The block spline is a thin and narrow SIP assembly that is inserted into recesses in the foam along the panel edges. These connections result in a continuous foam core across the panels. This helps to eliminate air filtration at the joints.
Another joint connection is Mechanical cam locks; create a tighter joint between the panels. In any type of connection, the seam along the sheathing must be covered with a continuous line of panel tape. Openings may occur at the edges and corners of the panel, and so the panel foam can be recessed to access lumber headers. Any opening within the SIPs that accept another enclosed element must be properly sealed.
Benefits and Drawbacks
1. SIP provides the tighter building envelope and the walls will have higher insulating properties.
2. Decrease in operating costs.
3. Buildings made with insulated panels can be easily dismantled and reused
4. Insulated panel properties (strength and thermal insulation property) will remain the same if reused.
5. It is cost effective as it can be installed easily
1. Quite poor performance with respect to the noise control.
2. Can be damaged by moisture. Better to use the panels with waterproof surfaces.
3. Panels should be properly protected from pests/insecticides.
4. Requires a proper mechanical ventilation system
5. Modification of the initial project is costly.
The Structural Insulated Panels come prefabricated and ready to be assembled, and hence it helps to speed up the construction.Also, it requires minimal equipment and workforce and hence cost effective.