ICF Concrete Walls

[TTForm]

Why is it necessary to have a solid, continuous wall of concrete for residential basements? Why wouldn't some sort of waffle configuration with the appropriate rebar suffice? An analogy: no one uses a solid block of wood to build exterior walls but instead uses stick framing. Plywood provides shear strength, and the joists/trusses provide the bracing. You use less concrete and more foam (R-value) when an ICF with a waffle configuration is used..

 

[Ron]

ICF can be used for basement walls, provided it is designed appropriately for the latera loads.

 

[concretemasonry]

Some of the older systems were a waffle-type system, but insect, pest and rodent could eventually use the EPS foam ties as an entry path. They are very bulky to ship and store.

The newer panel systems do not have this problem due to the ties used and a same panels (inside and outside) are cheaper to ship and more flexible since the same panels can be used for different wall thicknesses. The panel systems are actually easier to vibrate concrete properly into.

The concrete is very cheap, allows flexibility of design and the walls have more than enough shear strength if designed properly and plywood forms are gone and hopefully reused a few times after stripping.

Dick

Engineer and international traveler interested in construction techniques, problems and proper design.

 

[MiketheEngineer]

One reason - typically concrete is very cheap compared to any type of labor intensive forming system!!

And today - many interior/exterior wood walls are factory built and shipped to site. Straighter, quicker, dryer and done with $10/hr labor vs $40.00/hr labor!!

 

[TXStructural]

Waffle or screen grid ICF systems are available, but there is no universally accepted design methodology which fits ACI 318 and the IRC/IBC for these forms. See the linked site. There is a newer version (3rd edition) available from PCA for $$, but the linked one is still useful.

As noted, you probably want the strength and low permeability of solid concrete, particularly underground.

ICF construction is economical when you consider the minimal skill level required for construction, the speed of production, and the efficiency of the system in creating a combined structure and insulated building envelope.

Use of moderate strength, low cement concrete mix designs with local aggregates minimizes concrete costs. The cost of reinforcing is low, even when the prescriptive method is used. Labor cost is relatively low, compared to those for traditional form and finish labor.

 

[TXStructural]

The missing link:

http://www.huduser.org/portal/publications/destech/icf_2ed.html