Question:  What kind of vibrator should be used?  An electric vibrator with a 1-inch to 1.25 inch head and a 12-14 foot shaft.    Rent a second vibrator as a spare and to use in doing windows while the second vibrator is up on the scaffold.  You never know what the probability of failure of a rental yard vibrator is and its not uncommon to experience failures sometimes after only a short few minutes of use.

Question: I’m confused --- some ICF manufacturers recommend vibration of the concrete, others say to rod it or tap the outside of the form, and others say none of the above.  What’s right?

The word here is to "consolidate" the concrete, which eliminates air pockets and voids.  Elimination of these voids is required for the concrete wall to take on its full design strength.   It is required by code and general good construction practice.  Consolidation has three basic accepted methods, internal vibration with a concrete vibrator (this works the best), rodding (simply using a rod or piece of rebar and poking through the concrete multiple times, or tapping (tapping the forms with a hammer or other item). According to the CSA and American Standards, "all site placed concrete is to be consolidated sufficiently". Some manufacturers suggest you use the tapping method, and fill with a more fluid concrete (5-6" plasticizer induced slump). The problem is that an inexperienced crew often does not remove all the voids using this method.   A reason that manufacturers make different recommendations regarding vibration is their concern for blowouts.   There are variations in the relative strength of the block systems (during the pour and setting up of the concrete) from one manufacturer to another.   Those manufacturers who suggest not to vibrate their forms in part stems from this blowout concern.  AMVIC ICF blocks were specifically designed to be strong and tight enough to resist blowout when they are mechanically vibrated with an internal vibrator.   Mechanically vibrating the concrete in your AMVIC wall provides assurance that the wall will assume its full design strength. AMVIC recommends appropriate vibration.

Question: What's the right way to vibrate concrete?
There is an excellent guide from Concrete Construction magazine that answers that.  Click here to view.

Question:    Why haven’t we seen more ICF construction on the West Coast?
The construction industry changes slowly. ICF got its start in more severe climates of the Northeast U.S. and Canada where the energy savings were obvious and overwhelming.  Milder weather, abundant wood and business-as-usual made the west coast slower to adapt this new technology.   Rising energy costs, cost and quality of lumber, and consumer demand have been changing this.  ICF has been gradually moving west, particularly into areas with significant needs for air conditioning where the thermal mass of ICF drastically reduces electric bills for A/C.

Question:    What will ICF construction mean for the future value of my home?
 As energy costs continue to rise, and as ICF construction is more widely understood and appreciated it is reasonable to project that ICF houses will command a 10-15% premium over comparable stick-built homes in the not too distant future.

 Question:  Will I be able to find contractors and subcontractors who are familiar with and capable of building with ICFs?
There are contractors throughout the area that have built with ICF’s and others that are eager to adapt to the technology.  We maintain a listing of contractors that are familiar with ICF and AMVIC.  In addition we provide training for builders, that combined with site assistance from one of our consultants should overcome any problems associated with a first-time ICF build.   Selection of subcontractors will require a bit more screening than normal ... some are willing to learn new systems, and others may be inclined to avoid the job by  "high bidding" their bid.  A little shopping around should find subs who will work at prices comparable to conventional construction.  The only subs that have to do anything different are electrical, and to some extent plumbing.

Question:  Are there limitations on what kind of house you can build with ICFs?
No.  Virtually any design that can be built with conventional framing can be built with ICFs with almost no limitations.   There are special engineering requirements however, to cantilever out upper floors in a “garrison” style construction and it remains simpler to contain all ICF walls directly over the wall below 

Question: Does an ICF-built house look different than others?
From the exterior, there is no distinguishable difference in appearance.  On the inside, the interior windows will be recessed deeper due to the 11 inch walls and have more interior design articulation.

Question:  Do local building departments accept AMVIC?
 Yes, however some local officials may have more experience with this than others. Most of the Northern California and Nevada counties have approved ICF projects recently.   Most building departments have dealt with ICF construction previously and are knowledgeable about it.  AMVIC's system has been approved by the ICBO Evaluation Service, the primary construction product certification organization in the country.  The ICBO report number is ER-5948.  Download this ICBO Report.     If your onsite inspector is dealing with his first ICF project, it may take a little education and Amvic Pacific will assist you in that. 

Question:  Do I need an engineer to review my building plans?
ICF construction within seismic zones 3 & 4 (all of California and Northern Nevada) require that an engineer specify the structural elements of the design plan.  Proper engineering  will ensure that your construction project meets with local code requirements as well as ensuring proper design loads for hurricanes, earthquakes and other natural environmental conditions.  Our listing of AMVIC ICF-experienced structural engineers has qualified engineers for California, Nevada, and most other western states.  Engineers can perform all of the calculations, or can use the HUD Prescriptive Tables for ICF Construction, 2nd Edition.

Question: Can I construct radius and angled walls using AMVIC ICFs?
Yes.  Radius walls are constructed by removing sections from the inside side panel and bending the ICF into the required shape. Similarly, any angle can be made by miter cutting the form at the proper angle and using foam to join the edges. Ninety-degree and 45-degree corners are manufactured to speed construction since they are the most commonly used corner angle. A newly introduced product/service from AMVIC is custom manufactured curved blocks to build curved walls.  Available in three standard radii, if a custom radius is required, this is also available.  Contact Amvic-Pacific if you are interested in this.

Question:  Can I leave this product exposed to sunlight for extended periods of time?
Exposure of up to a year should not pose a significant problem. However, the ultraviolet light of sunlight will produce a light oxidation layer on the surface of the forms after extended periods of exposure. This oxidation does not indicate any detrimental effects to the wall form.   If the proposed finish is to be a stucco (or other hard coat material), it is recommended that the oxidized layer be brush away to provide a clean bonding surface for the stucco materials.  Ultimately the product needs to be protected with a covering coat of material.

Question: Does Expanded polystyrene (EPS) present a serious fire hazard?
The potentially flammable material in ICF walls is the foam. AMVIC is manufactured with a flame-retardant additive; these foams, unlike lumber, will not support combustion. Tests have shown that in the event of fire, EPS does not emit any gases any more harmful than those emitted by burning wood.. 

Question: I am concerned about mold and mildew in my new building. Will building with AMVIC block reduce or eliminate this problem? 
Mold and mildew are not a problem when building with the AMVIC wall system. Mold and mildew are fungi that grow in a moist atmosphere. They tend to form on the interior/exterior of walls where moisture condenses as a result of surface/air temperature differences. (For example, interior warm air contacting relatively cool spots on a surface becomes colder, increases in relative humidity and condenses.) Once the fungus forms, it can discolor the materials beneath it, deteriorate the materials' structures, and emit particles that cause unpleasant odors or affect the health of the building occupants. The AMVIC block will not allow condensation and resultant mold or mildew growth on either side of a wall as there are no thermal breaks in the wall; the inside wall remains at room temperature and the outside wall remains at the outside ambient temperature. The AMVIC ICF form the perfect air and thermal barrier. When used below grade, the inside of exterior walls should have a coating applied that allows moisture to pass through it should any moisture make its way behind the surface.   Water based latex paints "breath" and allow any trapped moisture to ventilate.

Question: How much does it cost to build with AMVIC compared to other building materials?
This isn’t a simple question to answer. Best case is that it the same or slightly cheaper than framing with 2X4 construction.  The worst case is  up to a 4% greater project cost.  The walls themselves cost more than equivalent wood framed walls. That’s only a part of the story however.  With an experienced crew, the walls will go up faster than stick framing.   There are construction savings on insulation, prepping for an exterior hard coat, reduced waste, and on sizing heating and air conditioning equipment, which can be reduced due to the thermal efficiency of the AMVIC building. If you are building on a hillside and would need to form a retaining wall, then building with the AMVIC system will be the same cost or even slightly lower than building conventionally.   Probably the best working assumption is to assume either the same cost as stick frame up to a 1-2% increase in cost to go with AMVIC, and slightly higher to use other ICF block systems.

Building with AMVIC is comparable in cost to building with 2x6 wall construction. The AMVIC wall will give you an effective insulation value of R32—much greater than a 2x6 wall—allowing you to save 50-80% on your heating and cooling costs and rapidly becoming cheaper than stick framing over a very few years. Contact your local rep, Amvic-Pacific for assistance in estimating your project.

Question: How does AMVIC compare to concrete block or poured wall construction?
When cured, the concrete in AMVIC walls is 50% stronger and use 30% less concrete than traditionally poured walls. While the cost of a bare block or poured wall is less, AMVIC provides insulation and furring strips, and is ready to finish, making it a cost effective and less labor-intensive choice.  AMVIC also is far less labor intensive to use where there are frequent openings and/or popouts as are frequently the case in residential construction.

Question:  Can I see an actual AMVIC project?
Yes. Contact Amvic-Pacific 530-265-9085 ... we will let you know when the next project will be going up in your area.