ICF FAQ
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Amvic ICF
Q - What are Amvic ICFs?
A - Amvic ICFs are hollow, light-weight "stay in place" forms made of two Expanded Polystyrene (EPS) panels which are connected by polypropylene webs.
During construction, the forms are stacked to the desired height then filled with concrete making stable, durable and sustainable walls.
They offer a "5 in 1" solution that provides structure, insulation, vapor barrier,
sound barrier and attachments for drywall and exterior siding in one easy step which dramatically reduces labor costs and construction time.
Q - What are the advantages of building with Amvic ICF?
A - Amvic ICF structures require 30-50% less energy to heat and cool when used in conjunction with other energy saving products.
They are also wind, fire and insect and rodent resistant as well as provide a safe, quiet and comfortable atmosphere for homeowners for many years.
Q - How long will an Amvic ICF structure last?
A - Concrete walls built with Amvic ICFs may last in excess of 100 years with minimal maintenance required to the walls.
This is at least 4 times longer than traditional construction.
Q - What ICF sizes are available from Amvic?
A - Amvic comes in 4, 6, 8 & 10" concrete cores, please contact us for more information.
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Why Amvic is Better
Q - Why is Amvic is the best on the market?
A - Below are some unique benefits offered by Amvic:
- Strongest form on the market
- Significant reduction in labor costs due to the form's unique design
- Dramatically lowered material wastage
In addition, Amvic offers excellent customer service and support through both the corporate office and extensive distributor network across North America.
Q - Is Amvic ICF easy to use?
A - Amvic forms are designed to make the construction process as quick and easy as possible in order to reduce labor costs.
Forms arrive on site pre-assembled, and the straight, 90 degree and 45 degree blocks provide for almost all shape requirements.
During the stacking process, taping, gluing and tying is minimized and the forms are fully reversible.
Q - What are the physical differences between an Amvic and traditional wall?
A - An Amvic wall is stronger, more soundproof, more resistant to natural disasters, better insulated, has a superior R-value, is more energy efficient and reduces air infiltration.
In addition it also provides numerous benefits from the thermal mass of the concrete.
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Construction
Q - How tall can you build with the Amvic ICF?
A - A structural engineer should design multi-storey structures built with Amvic, but the sky is the limit.
Q - Are there limitations on what kind of structure you can build with Amvic ICF?
A - No. Virtually any design that can be built conventionally can be built with Amvic ICF.
Q - Can I construct radius and angled walls using Amvic ICF?
A - Yes. Amvic offers 3 standard radii forms custom radius forms and custom radius forms can also be ordered.
ny angle that is required can be made by miter cutting the form at the proper angle and using foam to join the edges.
Q - Can the concrete in Amvic Forms be mechanically vibrated?
A - Yes. Amvic ICFs are one of few forms on the market that are engineered to withstand the internal vibration. In fact, this practice is strongly recommended by Amvic.
Q - Is a special concrete mix used for Amvic ICF?
A - Generally walls will require 3000 psi concrete or as specified by your engineer or code. Maximum aggregate size is 3/4" and placed at a 5-6" slump.
Q - What method should be used to pour the concrete?
A - Concrete can be placed using any one of several methods: concrete pump, conveyer belt, crane and bucket or by a chute directly from the truck.
A boom pump is far and away the easiest method using a 3" or 2.5" reducer in the hose to reduce the concrete velocity.
Q - What type of concrete consolidation does Amvic recommend?
A - Consolidation with an electric vibrator with a 1-inch head and a 12-14 foot shaft is ideal.
Q - We would like to build our house ourselves. Can we buy your system and install it?
A - Yes. You can install the Amvic Building System by yourself.
You should, however employ an ICF contractor to assist you with the final pre-pour check and concrete placement.
Q - How long do we need to wait after placing the concrete to backfill or put floor and roof systems onto the Amvic ICF Walls?
A - You should wait a minimum of seven days and follow guidelines set by your structural engineer.
Q - Where does the moisture from the concrete go once it has been poured into the forms?
A - Concrete must have water to gain strength and hydrating membranes are an essential part of concrete construction.
When ICF is used, the concrete achieves a higher strength than specifications because of this ability to keep moisture in the mix.
Eventually, all the water is converted to concrete crystals.
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How To
Q - How are doors and windows installed?
A - A wooden or vinyl buck is built to the desired rough opening size and incorporated into the AMVIC wall as it is being stacked prior to pouring the concrete.
Once the concrete cures, doors and windows are installed as usual into this opening.
Q - How do you run the electrical and plumbing?
A - Some of the utilities are placed prior to the pour, and others are done afterwards.
Services access cavities need to be cut before the pour. Just use a saw, utility knife or hot knife to cut through the blocks.
Then place the service pipes (or sleeves) in the openings. The gaps should be foamed to prevent concrete leakage during the pour.
Once the pour is complete cavities for wiring and plumbing can be cut into the surface using a router, chainsaw, or hot knife.
Place the services in chase. Generally, the Romex will be a friction fit into the groove. Occasionally a drop of foam is used to hold it in place much like a staple.
Make sure to observe all code requirements. If vents have to be run in exterior walls, they may need to be placed in the cavity of the block prior to the pour.
Generally, it is easiest to plan the layout of utilities to minimize use of the exterior walls.
Q - How is drywall attached?
A - Mechanically with drywall / gypsum screws into the polypropylene webs.
Frequently an EPS compatible adhesive such as Foam2Foam is used with the screws.
Q - How do you hang pictures?
A - Normal to lightweight pictures can typically be hung using a picture hanger with a nail driven anywhere into the sheetrock just like in frame construction.
Heavier weight objects will need to be hung by screwing or nailing into the imbedded web,
one of which is imbedded in the block running floor to ceiling spaced every six inches (3 times more than conventional construction).
The webs can be located much the same as in frame construction using either a magnetic stud finder (find the screws), or a sensitive electronic stud finder.
Once you've located one web the other webs will be easy as they are in multiples of exactly 6" from there.
If you need to hang something between the webs, you can use a molly type anchor into the sheetrock just like you would in frame construction.
(If necessary in extreme cases you can use a concrete drill and go back into the concrete and set a concrete anchor.)
Q - How are grab bars, towel bars, other fixtures installed?
A - Fixtures can be screwed into the webs (there is one every six inches), or installed using molly bolts through the sheetrock.
Alternatively backing can be installed between the sheetrock and the block.
One method is to use a hotknife and skin off 1/2 inch of the foam (flush with the webs) and install a strip of 1/2 inch plywood that is screwed into the webs wherever possible.
Then fasteners can be screwed into the plywood at any point. A second and easier method is to use Windlock Grapplers.
These are 4" x 6" perforated steel plates' corners dig into the foam and when sheetrock is applied over it they become firmly locked in place.
A fastener can then be screwed in at any point and it will pierce and lock into the Grappler backing.
Q- How do you connect internal frame walls to the ICF wall?
A - For regular walls; if the stud lands over a web, screw through the stud with a 3" deck screw and connect to the web.
If it doesn't span a web, you can use Grapplers (see above) or just spring the stud out and use an adhesive such as Foam2Foam polyurethane foam,
liquid nails or similar and glue the face of the 2X to the foam.
In the uncommon case where the frame wall is a shear wall, then use anchor bolts or Simpson Ties just like you're installing a ledger and bolt the stud to the concrete.
Q - How are exterior finishes attached?
A -Stucco (acrylic or cementitious) is adhered directly to the foam.
Wood, plastic or metal cladding is mechanically fastened to the imbedded plastic ties.
Stone and brick are attached according to design specifications.
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Attachments/Finishes
Q - What does an Amvic House look like when it is finished?
A - An AMVIC home looks like any conventional new home on the outside and inside. The window sills are deeper since the walls are thicker.
Very few people can tell the difference between ICF construction and other types of construction.
Q - What kind of siding can be used on the Amvic Building System?
A - Virtually any conventional exterior finish can be used with the Amvic Building System.
Proper planning should be considered. Check the AMVIC Tech Manual for details.
Q - Can we use stucco on the Amvic Forms?
A - Yes. Any type of stucco can be applied directly to the EPS Forms.
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Architectural/Engineering
Q - Does Amvic provide engineering for Amvic walls?
A - No. Amvic does not engineer specific projects.
A local engineer that is familiar with local codes and building conditions should consult the Amvic ICF Tech Manual for engineering guidance.
Q - Do you have to use special plans for the Amvic ICF System?
A - No. Conventional house plans can be used; you must simply have the exterior wall dimensions increased to accommodate the Amvic walls.
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Cost & Performance
Q - How much does it cost to build with Amvic compared to other building materials?
A - 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 studding, vapor barrier, 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 more cost effective 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.
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.
Q - How does Amvic compare to concrete block or poured wall construction?
A - 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.
Q - What will ICF construction mean for the future value of my home?
A - 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.
Q - What thermal efficiency results will I achieve with Amvic ICF?
A - R-Value is a term given to the property of any material to "resist" the conduction of heat. R-Value as a property is legitimate.
The functional design of the laboratory determination of this property, relative to commercial insulation and building materials,
is flawed at a fundamental level since performance predictions using heat transfer calculations based on tested and published R-values alone do not accurately predict real-world performance.
Amvic ICF alone has an R-Value of 22; however, when the mass and thermal efficiency of the concrete core is taken into account,
Amvic ICF can achieve a thermal efficiency equivalent to R-50 depending on the size of the core.
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Health & Safety
Q - Does Expanded polystyrene (EPS) present a serious fire hazard?
A - No. Amvic is manufactured with a flame-retardant additive which 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.
Q - Will my Amvic ICF home provide any hurricane or tornado protection?
A - With the proper roof configuration, Amvic ICF homes are very resistant to tornados and hurricanes.
In most cases, damage is to the external finishings only.
Q - I am concerned about mold and mildew in my new building. Will building with AMVIC block reduce or eliminate this problem?
A - Mold and mildew are not a problem when building with the Amvic 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.
Amvic ICF provides 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.
Q - Do the Amvic forms "off gas"?
A - No. The Amvic forms are inert, non-toxic and do not "off gas".
Q - Do I need to worry about termites?
A - While termites don't feed on EPS like they do wood, they can tunnel through EPS to reach a food source.
While this is infrequent, there are several ways of installing the block to create termite barriers that should satisfy building inspectors.
Amvic can assist you with alternative considerations.
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ICF Tech. & Install. Manual
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