The present invention relates generally to electrical boxes for use in building construction that utilizes insulated concrete form building systems.
Recently, many building systems have become available that utilize insulated concrete forms to form concrete walls, floors, ceilings and other structural elements. With these systems, concrete is formed into the desired walls, floors, ceilings, and other elements using concrete forms that are made from a rigid foam insulating material. These systems are commonly referred to as Insulated Concrete Form (ICF) systems. In these systems, the insulated concrete forms are left in place after the concrete is poured thereby creating an overall insulated concrete element that includes the concrete and the insulated forms. These systems are typically modular and relatively easy to assemble. These systems also provide very well insulated and very sturdy structural elements that are relatively cost effective and very energy efficient compared to other building methods. Due to these advantages, this type of system has become more common in recent years.
One of the problems with using ICF systems in construction is that this building system makes the installation of electrical outlets and switches in walls, floors, and ceilings built using an ICF system potentially more difficult compared to conventional wood framing systems. In the case of conventional wood framing systems, a basic structure may be completely rough framed prior to installing any electrical lines and boxes. Once the rough-in framing is complete, electricians are able to install electrical boxes by nailing them to studs and running electrical wires before the installation of any drywall or other wall finish. However, when using ICF systems, the methods used to install electrical boxes and wires are typically different than those used in conventional stick framing.
Currently, two different general approaches to placing electrical boxes and lines in ICF systems are employed. In the first approach, the electrical boxes and electrical conduit that are needed in the ICF formed elements are all installed into the forms before the concrete is poured. In this approach, the electrical conduits are, in most cases, encapsulated within the concrete once it is poured into the insulated forms. In the second approach, the electrical boxes and wires or conduit are installed after the concrete is poured. In this approach, openings are cut into the foam forms after the concrete is poured and the electrical boxes are fastened to the concrete after the concrete has at least partially cured. Channels are also cut into the foam and the wire or conduits are installed into these channels. In both approaches, conventional electrical boxes, conduits, or Romex type wire are used.
When using the general approach in which the electrical boxes and conduit are installed before the concrete is poured, conventional electrical boxes are typically modified so that they may be attached to the insulated forms using fasteners. This modification and attachment of conventional electrical boxes can be vary labor intensive and can add significantly to the labor requirements associated with using the ICF system. In order to illustrate this problem, the typical approach to installing an electrical outlet box in an ICF wall prior to pouring the concrete will be described in more detail. In this example, it will be assumed that there will be an incoming electrical conduit and an outgoing electrical conduit, both of which are to be connected to the electrical box to provide conduits for pulling electrical wires after the concrete has been poured. This is the most common electrical box configuration used when electrical boxes and conduit are installed within the concrete of ICF systems.
As mentioned above, ICF systems are typically modular systems made up of standard sized blocks or panels that are assembled on site to create an overall form that is then filled with concrete. In most systems, the standard sized blocks have a uniform height, for example 16 inches, and have two, spaced apart, foam sidewalls having a particular sidewall thickness, for example 2 inches. Other systems use blocks that are molded and that do not have a constant sidewall thickness but instead have a contoured inner wall surface that causes the foam sidewall thickness to vary throughout the block. For the example being described, it will be assumed that blocks having a constant wall thickness are to be used.
As the blocks are assembled to create the overall forms, openings are cut into the foam blocks and the electrical boxes are installed into these openings. Conduit is then installed within the overall form interconnecting the electrical boxes. The conventional electrical boxes are typically modified so that they may be placed in the openings cut into the foam blocks and attached to the foam insulation of the insulated concrete form as the foam blocks are assembled into the overall forms. For illustrative purposes, the following example will be described using a conventional single gang metal electrical box that is approximately 3½ inches tall, 2 inches wide, and 2 inches deep.
In order to prepare the box for installation, several modifications to the box are typically made. First, in order to accommodate the connection of the two electrical conduits, two conduit sockets are installed on the back of the box by removing two knock-outs from the back wall of the electrical box and attaching the two conduit sockets in the conventional manner so that the conduit sockets extend outward from the back of the electrical box. Next, a mounting plate is fabricated and attached to the back of the electrical box. This mounting plate is typically made from a readily available material such as plywood that is cut to a size somewhat larger that the back of the electrical box, for example, approximately 6 inches by 8 inches. Also, holes are cut into the plywood mounting plate to allow the conduit sockets to protrude through the mounting plate. The mounting plate is then attached to the back of the electrical box using conventional fasteners such as wood screws. Additionally, depending on the thickness of the foam insulation used in the ICF system and depending on the depth of the electrical box being used, shims may need to be used as spacers to cause the electrical box to extend out from the mounting plate a proper distance. This proper distance is a distance that causes the electrical box to extend slightly beyond the outer surface of the foam sidewall when the electrical box assembly is installed into the opening formed into the sidewall of the foam block. This configuration allows electrical outlets or switches to be installed into the electrical box in the conventional manner after drywall has been installed over the ICF wall and over the electrical box that extends slightly from the outer surface of the insulated foam of the insulated concrete wall.
Typically, the openings for the electrical boxes are cut into the upper edge of the foam blocks as the foam blocks are being assembled into the overall insulated concrete form. The modified electrical box assemblies are then inserted into the openings cut into the top edge of the foam blocks with the mounting plate pressed snuggly against the inner surface of the sidewall of the foam block. The electrical box assembly is then attached to the sidewall of the foam block by installing long screws with large washers from the outer surface of the foam block, through the foam sidewall, and into the plywood mounting plate thereby pulling the mounting plate of the electrical box assembly tight against the inner surface of the sidewall of the foam block. Once the electrical box has been attached to the foam block, electrical conduit sweeps may be attached to the conduit sockets of the electrical box assembly and conduit may be attached to the conduit sweeps to interconnect the electrical box assembly with other electrical box assemblies.
In the second general approach used to install electrical boxes and lines in an ICF system, the entire ICF system is assembled and the concrete is poured prior to installing the electrical boxes and lines. Once the concrete has been poured, openings for the electrical boxes are cut into the foam sidewalls and channels for running wires or conduit to interconnect the electrical boxes are cut into the foam sidewalls. These openings and channels may be cut using a router, hot-knife, chainsaw, knife, saw, or other suitable tool and this process is typically a fairly labor intensive process that increases the costs of utilizing this building system. Once the openings and channels are cut, conventional electrical boxes are installed into the openings by power nailing or otherwise fastening the electrical boxes to the concrete wall that has been formed inside the insulated concrete forms. This may be a rather difficult process and may require the use of shims to position the box such that it slightly protrudes out from the outer surface of the foam sidewall of the ICF system in the same manner as described above in the previous example. After the boxes are attached to the concrete, wires or conduit may be installed into channels to interconnect the electrical boxes.
As described above, both of the currently used general approaches to installing electrical boxes and lines in ICF system walls or other elements are more labor intensive than conventional methods of installing electrical boxes in conventional stick framing systems. This increases the costs of building and time required for building when an ICF system is being utilized compared to a conventional building system. The present invention provides improved methods and improved electrical boxes that substantially reduce the time and labor requirements for installing electrical boxes in walls and other elements of an ICF building system.
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