Adapting Designs and Plans for AMVIC ICF Construction
- 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.
- 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.
- 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.
- Curved walls of nearly any radius can be built with far less difficulty than would be experienced in conventional construction.
- Angle corners: There are 90-degree and 45-degree blocks pre-manufactured. Corners of any other degree can be field constructed with no difficulty.
- Blocks are 16 inches 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.
- Up to 4 stories can readily be built and engineered.
- Rim joists/floor ledgers can be installed at any height on the walls, irrespective of the block courses.
- Typically six-inch block will work in all situations. Added strength can be gained by increasing the rebar schedule typically. If 6-inch block is used it will save 25% on concrete. The one case where 8-inch block is usually going to be necessary would be where more than 7-8 feet of retaining is involved, or where a wall is taller than 12 feet without an intervening diaphragm connection. In any case, the structural engineer is the final authority.
- The installer, as required, can accommodate any height of windows or doors.
- 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.
- Projections and overhangs are important considerations. The most straightforward approach is to support upper story concrete walls by placing them directly above a corresponding concrete wall below. Otherwise, detailed structural engineering and steel beams will be required.
- 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 as wood or steel (you can't readily switch back to ICF and concrete).
- Raised concrete floor systems are also possible at about the same cost as wood systems using ICF type forming systems.
See www.litedeck.com for one excellent system.
- Bumpouts. Short wall bumpouts should extend outward by 30" ideally (but at least 18") using 6" block and 20" when using 8" block.
- 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.
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.
Suggested reading: A comprehensive guide to Designing Energy Efficiency in New Home Construction
Additional extended design notes are available for use in the
Working Drawing/detailing phase of design by the architect/draftsperson. Download Complete Design Notes
Full CADD architectural details are available for download:
www.caddetails.com (Go to the Company tab, select Amvic, login as guest.)
Download this Design Guide in Adobe Acrobat PDF format