Monday, April 11, 2011

ICF House Plans

There are thousands and thousands of different house plans available from designers, architects, plan books and on the internet. But virtually none of these have been specifically designed to utilize ICFs or insulated concrete forms.

Framed construction is the most common form of residential construction, so most designers do not create many plans specifically for ICFs. But many designers are often willing (sometimes at no charge) to modify their plans for a client who wishes to utilize ICFs. I do not charge extra to modify one of my existing plans for ICFs or to design a new home using ICFs.

While ICFs are a fairly common building material, some aspects of ICF home construction differ from more traditional stick-frame construction. One main difference is the thickness of the walls. The most common ICFs use about 6” of concrete in the middle of the wall. Then there is a layer of foam on either side, typically 2” to 2 ¾”. This brings the total wall thickness to 9” or 9 ½”. Standard 2x4 framed walls are only 3 ½” thick while 2x6 walls are 5 ½”.

In most rooms of a home, the additional wall thickness is no problem. Without a tape measure, you cannot tell the difference between a living room that is 22’ across from one that is 21’-6”. However, in small rooms such as a bump out for a master bath, this extra wall thickness can reduce the interior space by too much. This is easily fixed by slightly increasing the exterior dimensions of that area. Small rooms against exterior walls is one area to be aware of when converting a plan to utilize ICFs.

The floors of multistory ICF homes do not use stacked platforms between stories as with stick-framed homes. Typically, ledgers are attached to the ICF walls with special steel brackets to support the floor platform. This configuration allows the ICF wall to be continuous from the footing to the roof. There are no issues with this configuration; it is just different than stick framing.

But be assured that virtually any home design can be converted to utilize ICFs with a little effort and at possibly no extra cost. If you really want an ICF home, check with your designer to see if they can modify the plan for you. If not, many ICF manufacturers provide a list of designers who are very familiar with this product. ICFs are a great product; don’t let your plans hold you back.

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