Insulated Concrete Panels (ICP)
Insulated Concrete Panels
Rubber Seal Beneath Sill Plate
Framing: "L" Buck Corners
Energy Heel Truss
Rob Derksen's House
Submitted on 10/10/2007 by Michigan Geothermal Energy Association.What makes a house energy-efficient? Are the extra benefits worth the price? Rob Derksen incorporated new and innovative building techniques and products in his new house in Michigan, which are documented here to allow you to learn more about the home's energy-saving features.
Rob's basement uses Benchmark's new Insulated Concrete Panels (ICP), which are made of 2x6 steel studs placed 12 inches on center. Two-inch Dow foam is placed on the inside and the outside of the panel. Once the panels are in place, concrete is poured into the panels.
The benefits of this type of basement construction include:
1) Drier basement, since there's no direct contact between the earth and the concrete to wick moisture.
2) Warmth, because the foam panels provide R-20 insulation value.
3) Lower heating costs - approximately 1/3 of the cost to heat a standard poured or block basement.
4) Convenience, because the basement is ready to finish, with no additional framing needed. Drywall can be installed right on top of the furring strips provided.
Another energy-saving technique is to use a special rubber seal beneath the "sill plate" to seal air leaks from penetrating cracks between the framing and the top of the basement wall. Leaks in this area can be significant and contribute to higher energy bills. Further inspection of this area will be made as the rest of the house is constructed. Any visible gaps will be sealed with low expansion foam.
"L" buck corners are a method of framing the exterior corners of the home. This type of framing actually uses one less piece of lumber and allows the insulation to extend all the way to the exterior corner of the house. Traditional framing methods leave an air gap in the exterior corner. Corners that lack insulation not only waste energy, but can lead to mold or mildew forming. This is because the corner is cold in the winter time, and the warm and humid air inside can condense on the cold surface, causing mold.
A similar technique allows insulation to be placed in the wall where an inside wall abuts to the outside frame. Older techniques created a pocket of air in a "box" formed by the wall studs. In the new method, one of the studs is turned 90 degrees so insulation can be placed behind it.
An energy heel truss is simply a roof truss that has a "raised heel". In traditional framing, the heel height may be too short to allow for enough insulation over the outside wall. Inadequate insulation in this area is the primary cause for ice dams in cold climates. By raising the heel of the truss to at least 10 inches, you can get adequate insulation to avoid ice dams and the damage associated with them.
Caulking and foaming are essential to eliminate the abundance of cracks in the framing of a home.
A great deal of time and caulk was spent "energy sealing" the home. This is a project that the average homeowner can tackle with a little direction and some spare time. The thing to remember is that, if you are in doubt, "caulk it".
Around windows and doors, I recommend the use of low-expansion foam. Please note that the use of high-expansion foam will cause damage to your window or door frame and/or impede the proper operation of the unit. Using fiberglass around windows and doors will not stop air from leaking into or out of your home.
The following areas tend to be the best place to start:
1) Bottom and top plates (this is the bottom and top framing of a stud wall)
2) Exterior corners and corners where an interior wall meets an exterior wall
3) All electrical, plumbing & heating penetrations both into the attic and through exterior walls
4) Around the sill plate (this is the area where the floor joists sit on top of your foundation wall, there can be irregularities in the concrete that are not sealed by the gasket material discussed earlier in this tour)
5) Joints where two stud come together as shown in the photograph.
The house wrap I chose to use for my project is Tyvek. Tyvek is designed to perform 3 main functions.
1) To resist air penetration. Air penetration or infiltration is the source for the single largest energy loss in a home. By reducing the air infiltration, a smaller heating and cooling system can be installed, therefore saving installation cost as well as lowering energy bills.
2) Bulk Water Hold out. Because my home is mostly brick, I want to protect my sheathing against bulk water. A properly installed Tyvek system can keep the water that penetrates my brick or any other siding material from soaking my sheathing and causing rot.
3) Moisture vapor permeance. The way Tyvek is made allows it to let moisture vapor escape. In tightly constructed homes, such as mine, moisture that is in the home or in the exterior walls needs to be able to escape so as not to cause any moisture related problems hidden in the wall cavity. Tyvek accomplishes this task
As I stated, a properly installed housewrap is critical to get the performance you expect. I took the time to tape all of the seams, and, as you'll notice in the photograph, I also taped the flanges of the windows.