Energy Efficient Wall System

Sponsored by:
Energy Concrete Structures, Eco Block Distributor
Email Jerry Cox 828-361-2757

We chose an ICF wall system because of the benefits they offer a solar heated home. They provide very good insulation to keep the heat inside, and a lot of thermal mass to even out the temperature fluctuations common to solar homes. ICF stands for insulated concrete forms. Concrete is poured inside forms that also provide insulation. With this system, the wall has the strength of reinforced concrete and lots of insulation for energy efficiency. Another reason we chose this sytem is the ease of construction. I design homes, but I am not a builder. Jerry Cox was very easy to work with. He sponsored a class where I learned how to design and build an ICF wall system. Since taking this class I have been able to design ICF homes for my clients who want to use the same system.

The footers are ready to pour and we have assembled some of the ICF forms for the first course.

Pouring our first footers. We needed a pump because the concrete truck could not get close enough to the cabin.

Brian Schmitz of Georgia Mountain Concrete is a friend of mine who is doing all of my concrete work. He reccomended that we set our first course in the wet concrete for a much stronger bond. We ran a stringline for alligning the tops of the first course. At first the concrete was so wet that the ICF blocks kept floating up. But after a few minutes they stayed where they were set. When the footers dried, they are bonded very well to the ICF blocks.

Here Brian is cutting one of the ICF forms to fit in a wall. These forms are very easy to cut. The marks on the form help you make straight cuts.

The next day a lot of good friends showed up to help us put up the walls. They ran a little ahead of our planning and the walls ended up a little crooked. An advantage of this system is that we can take it apart and rebuild it so quickly. Each block is 48" long and 16" high, the size of six concrete blocks, but so much lighter! Next we built the window frames (bucks) and rebuilt some of the walls. We used strong corner braces that we can adjust to make the walls straight and square. Then we built the corners of the walls before filling in the rest of the walls. This allowed us to build the walls accurately.

Because I got very busy with work, I hired a good friend of mine to build the window frames (bucks). The purpose of the buck is to prevent the concrete from pouring into the window opening area when the ICF walls are filled with concrete. The bucks also provide a way to attach the windows. The ICF company reccomends two types of bucks. One is a very nice extruded vinyl system that fits perfectly to the ICF walls. My limited budget would not allow for these. The other type is using pressure treated 2x12 boards. I don't like the idea of pressure treated wood around every window and door. Besides the issues some have with the chemicals that are used to treat the wood, there is the possibility of moisture causing the wood to warp, opening up the home to air and water leaks. Being a designer, I decided to come up with a cheaper and better sollution.

For the actual buck material I found surplus vinyl decking at a construction salvage yard. These planks are made of vinyl and cedar chips. They were old and sun faded. Vinyl decking is not strong enough to withstand the force of wet concrete, so I designed a system of reinforcement with 2x4 lumber and OSB panels cut into 12" strips. 1/2" anchor bolts are mounted into the vinyl to anchor it to the concrete wall. The OSB and the lumber provide strong bracing around the edges of the window opening. After the concrete is cured, the wood and OSB will be removed, leaving behind the vinyl for window attachment. The advantages of this system are many. It costs a lot less. The wall insulation is much tighter to the window frames. I used salvaged materials. The vinyl material will not warp or rot. It is very well anchored to the wall. I can also take advantage of a much better way to install the windows using a clip mounted system. If I ever have to remove the windows, I will be able to do this very easily from the inside of the home. The windows will be recessed over two inches from the outside surface of the wall, allowing for much better protection from the rain. I can stucco around the window openings for a very clean, attractive look. My ICF supplier likes my window buck design.

Here is a buck sitting on a single ICF form, to illustrate how they work. In the house, the buck will have ICF forms around the bottom, sides, and top, with concrete poured between the white foam panels. The 2x4 cross braces give the buck enough strength to hold back the wet concrete. The round holes in the bottom of the buck are for pouring concrete into the wall section below the window. The boards and OSB will be stripped off when the concrete is cured. All that will be left is the dark brown vinyl planks, anchored to the concrete with the anchor bolts. The windows will be attached to the vinyl planks.

Here are some photos of these window frame bucks installed into the walls. They are reinfirced with 2x4 lumber across the inside, and around the outside of each window.

Next came pouring the ICF walls. This is very tricky. If the concrete is too wet, it will blow out the foam blocks. If it is too dry, it will not fill in all of the areas inside the wall. While the walls are being poured, they must be carefully watched to make sure the blocks or window frames are not stressed. Everthing went very well. The cabin was poured and anchor bolts were set in a half day.

If you would like more information about this innovative product, see the top of the page to contact Jerry Cox.

Would you like to see this home under construction?
Come to the next Mountain Home Show, and you will get an invitation to our open house.
For more informaiton, click on the link to "Detailed information about the home show."
If you are interested in building, you may also be able to make an appointment to visit.
Click on "Email Richard" to make an appointment. Or perhaps you would like to observe the construction of this home on line.
Click on "Construction Diary." You are welcome to visit often as we continually update it.

How to Contact Richard C. MacCrea
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