Adapting Designs and Plans
for AMVIC ICF Construction
DESIGN PHASE

Updated April 2006

1. The main difference in building an ICF structure as opposed to frame construction is that you are dealing with thicker walls and need to accommodate that in the design. If using "6-inch" blocks, there is 6 inches of concrete sandwiched between two 2-½ inch EPS foam panels for a total wall thickness of 11 inches. 8-inch block is 13 inches in finished thickness.

2. To maintain the same interior dimensions of a stick plan, stretch the exterior dimensions on all sides. As interior walls are usually framed conventionally, no other overall size adjustments are necessary.

3. Generally, significant compromises to the design to accommodate the block are not recommended. Make the design work within normal good design practices and the block can be adjusted to accommodate that.

4. Curved walls of nearly any radius can be built with somewhat less difficulty than would be experienced in conventional construction.

5. Angle corners: There are 90-degree and 45-degree blocks pre-manufactured. Corners of any other degree can be field constructed readily.

6. Blocks are 16 inches high. (Exception: the 10-inch core blocks are 24" high) Two inches can be taken off by ripping either the bottom or the top of AMVIC block. Blocks can also be ripped in the center if needed, and with the new reversible design, the two half blocks are usable interchangeably. It is convenient, but not essential that the overall height of the walls either be right on the course intervals (16") or if it is greater than, then the greater than should be by at least a ½ course height (8") or more.

7. Up to 6-8 stories are readily feasible.

8. Rim joists/floor ledgers can be installed at any height on the walls, irrespective of the block courses.

9. Typically six-inch block will work in most situations.  8-inch block is usually required where more than 7-8 feet of retaining is involved. In any case, the structural engineer is the final authority.

10. The installer, as required, can accommodate any height of windows or doors.

11. Consider including full basements.   It is relatively low cost space, is easy to build with Amvic ICF, makes good use of sloping sites.  We have excellent design details and waterproofing systems to facilitate design.

12. Remember that concrete walls cannot be supported by wood framing below.  Cantilevers and setback upper story walls can be accommodated but generally are more expensive and where cost is a consideration should be approached with some caution.  The most straightforward approach is to support upper story concrete walls by placing them directly above a corresponding concrete wall below. If the design dictates otherwise, early discussions with the structural engineer are highly advisable. 

13. In some cases it may make sense to switch over to conventional framing in a segment of the wall and that is acceptable. In such case, all structure above the wood or steel frame should continue upward as wood or steel (you can't readily switch back to ICF and concrete).

14. Raised concrete floor systems are also possible at roughly the same cost as wood systems using ICF.  These systems form concrete drop beams that are the sole support of the floor.  The advantages include excellent thermal and acoustic isolation between floors and a high thermal mass decking system that is ideal for radiant heat or for designs featuring passive solar.   The Amvic AmDeck system is the newest and most advanced system on the market for poured in place elevated concrete floors, external decks, or roofs.  It can free span up to 40 feet, and up to 20 feet can be poured without requiring temporary shoring. 

15. Bumpouts. Short wall bumpouts should extend outward by 30" ideally (but at least 18") using 6" block and 20" when using 8" block.

16. To complement the energy-efficiency of the ICF wall systems, we strongly encourage using EnergyWise Structures to design and specify your HVAC system and other energy related elements of the structure.  More details.

If you are building either in a rural area or in the rural/urban interface area where you have a potential for wildfire, then our Firesafe Tips for New Construction outlines additional design considerations.
 

Full CAD architectural details are available for download at: www.amvicsystem.com

Other Suggested reading:  A comprehensive guide to Designing Energy Efficiency in New Home Construction.