Overlaying ICFs onto Existing Frame Plans

Commonly used methods

Method 1: Line up exteriors of the walls and reduce interior dimensions slightly

Method 2: Line up interiors of the walls and increase exterior dimensions slightly

Method 3: Line up centers of the walls and let wall encroach a little to both inside and outside.

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Comments:

Peter Juen- SE Florida Polysteel Inc.
Phone: 561-225-5404
Email: seflpolyst@aol.com
In Florida, we have a lot of concrete block houses. For overlaying ICFs over existing plans for concrete block walls, the same methods as frame apply.

Pieter VanderWerf- Building Works
Email: pvander@buildingworks.com
I recommend lining up the interior sides of the walls and letting the exterior dimensions of the ICF building be a little bigger. Reason #1: You don't have to change any of the interior dimenisons so there's a lot less change work to do on the plans. Reason #2: this preserves the interior space, which is important to buyers and often has already been promised at a specific square footage.

Lud - Tricom Construction
Email: ladell@rcslv.com
Another plus for ICF's- you can attach thinner wallboard(1/2" instead of 5/8") The form backing offers the strength, which is more than what 5/8" offers on a stick wall.

Joe Villeneuve - Concepts in Design
Email: joe@conceptsindesign.com
I recommend a form of Method 3. The reason I use this method is because it allows me to minimize waste of the forms. Since most forms can be layed out using a 48" grid (from outside of forms) and it is rare to find conventional construction using this same grid (although they should too), I can adjust the exterior walls to get as close as I can to a 48" grid ... and reduce waste.