Re: Insulated Concrete Forms (ICF)
From: Jerry McIntire (
Date: Thu, 7 Jan 2016 20:55:41 -0800 (PST)
Insulated concrete forms use lots of concrete, which has a bigger
environmental impact than lumber (the equivalent structural component), and
plastic foam to insulate which also has a greater environmental impact than
recycled cellulose which is easily used in a wood-framed structure.

If thermal mass is needed in a passive-solar design, ICFs don't provide it
because the concrete is insulated on both the exterior and interior.

What are they good for? Basement walls maybe.

SIPs panels are another alternative I like more than ICFs. They have a
greater R (insulation) value per wall thickness than ICFs and have equal or
better structural value if polyurethane foam is used in the SIPs. They can
be used for roof, wall, and floor panels and they save on labor costs.

Jerry McIntire

On Thu, Jan 7, 2016 at 12:05 PM, Thomas Lofft <tlofft [at]> wrote:

> ON Date: Wed, 6 Jan 2016 10:39:27 -0500
> From: Miranda Castro <mirandacastro [at]>
> Subject: [C-L]_ Insulated concrete forms
> Miranda wrote:
> Hi All
> I am curious as to whether any cohousing group has used "insulated
> concrete forms? in the construction of their homes -
> or researched this and decided not to and if so why.
> Thanks so much
> Miranda
> Hi, Miranda et al.:
> At Liberty Village, MD,
> there was one home built with ICF (Insulated Concrete Forms) which is now
> 15 years old.
> I witnessed the construction, but was neither the builder nor the project
> manager, however, I do now own the home.
> I have otherwise watched the development and use of this technology and
> consider it very beneficial.
> However, I'm not sure how its current cost balances against all its
> benefits.
> Local construction costs will depend upon both material and labor typical
> local cost variables.
> Benefits: It creates a very airtight structure,
> It's very highly resistant to external noise;
> It's well insulated and totally air infiltration resistant except at
> openings for doors, windows and utilities which must be well sealed;
> It's insulation levels can be upgraded by thicker ICF's at the onset.
> The roof structure may be conventional framing or trusses with structural
> insulated panels (SIP's) used for roof structure.
> Constraints:
> It requires a very well trained and experienced crew and manager to be
> well constructed;
> Like any other construction it is still totally dependent upon
> knowledgeable soils testing and foundation construction;
> Effective use for a PassivHaus would still require high insulation values
> for doors and glazing, possibly triple glazed;
> I expect long term value will be very high, offsetting possibly higher
> initial expense.
> Similarly, this house was also developed with Ground Source Geothermal
> Heat Pumps for Heating & Air Conditioning (HVAC).
> These also added front end expense in 2000, but very high value long term
> benefits with HVAC operating expenses less than 50% of comparable fossil
> fuel costs.
> I personally believe strongly in making front end investment for long term
> value, so I have added photo-voltaic (PV) panels to the rooftop.
> In this case, the house was planned for perfect southerly roof orientation
> and all roof penetrations were avoided.
> In 2014, 36 - 255 watt PV panels were added for a 9.2 KW DC system,
> eliminating any electricity cost from last May through this month.
> The house is about 2,400 sq. ft. on 2 levels, with three baths, four
> bedrooms, 2 kitchens, 2 living-dining areas.
> It is currently used as an upper and lower level duplex, and has an
> attached 1 car garage.
> It is now offered on the local real estate market for $385,000, including
> a 30,000 sq. ft. lot.
> All inquiries are invited.
> Tom Lofft
> Liberty Village, MD
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