SPF BUILDING SCIENCE: SPECIAL INDUSTRY STUDY
As an insulation material, ccSPF provides superior insulating performance at a given thickness, is inherently
moisture resistant, typically serves as an air barrier at just
1” of thickness6 and provides vapor barrier performance
at 2” thickness.
7 The multi-functionality of ccSPF makes
it ideally suited for use as an exterior insulating system
that provides a comprehensive building protection layer.
It adheres well to the mass wall, provides seamless monolithic protection and expands to seal penetrations and
other irregularities that are inevitable in wall assemblies.
In addition to its performance attributes, designers and
general contractors often find that ccSPF is a cost-effective solution that can simplify trade scheduling, improve
speed of installation and increase reliability compared to
alternative insulation systems.
As shown in Table 2, XPS, EPS, PIR and mineral wool
board products may not deliver the moisture and air infiltration protection that architects and builders require.
Consequently, these systems require additional layers or
detailing to provide sufficient moisture, air and vapor
control to adequately protect the building. Although
these extra layers result in additional costs associated
with the insulating system, they are often treated discretely rather than included in a total insulation system
A SYSTEM APPROACH TO INSULATION COST
Chart 1 breaks down the relative individual costs associated with each insulation system option based on meeting mid-climate Zone- 5 insulation requirements (R- 12).
Closed-cell spray polyurethane foam was considered
along with XPS, EPS, PIR and mineral wool board insulations. For the purpose of this cost comparison, only the
insulation, air barrier and moisture control measures were
included since the cost for the remaining components are
neutral relative to established wall system design.
In this comparison, the average of a sheet membrane
system and fluid applied bituminous layer was used
because they are the most commonly applied water/
air barrier layers for protection of mass wall systems.
Using the RSMeans database, the additional cost associated with installing these layers, based on national
averages, was determined to be $2.91 and $2.60 per
square foot respectively. When you include the cost of
these additional layers plus sheathing tape costs to seal
board joints, ccSPF becomes the clear choice as the external insulation system for mass wall designs. See the
Insulation System Cost References at the end of this
paper for additional cost data.
When one takes a system approach to comparing in-
CASE STUDY: MASS WALL CCSPF SYSTEM EXCELS AT
sulation costs, ccSPF becomes the preferred system
for mass wall design and construction. By looking at
insulation system costs holistically, a more accurate com-
parison can be drawn than by looking at the components
alone. Although individual project costs will vary by loca-
tion, the data indicates that choosing a ccSPF insulating
system for mass walls can result in significant costs sav-
ings in excess of 30% relative to board insulations that
often require additional air and water infiltration control
layers. In addition to these significant savings, contractor
feedback reveals that one of the greatest benefits when in-
stalling a ccSPF system is the simplicity and time savings
associated with using one material, one labor pool and
one time around the building. By coordinating a single
trade with the cladding installation, significant project
efficiencies can be realized that can often outweigh the
initial material cost savings alone.
Informed design and engineering firms have utilized high
performance mass wall systems with ccSPF for decades.
One such example is the 138,000 sq ft renovation and
expansion of Merrimack High School in Penacook, NH.
To meet the project’s energy savings criteria, the school
district worked in conjunction with the spray foam contractor (FOAM-TECH™), the design firm (Banwell Architects) and associated engineering firms to select a high
performance wall system using ccSPF on the exterior.
The design qualified Merrimack High School as the first
project in New Hampshire to meet the performance criteria of the Collaborative for High Performance Schools
program. Not only did the exterior ccSPF system meet
the program’s energy efficiency requirements, its superior air tightness and efficiency facilitated a 25% reduction in HVAC system sizing at a significant project cost
savings of $6.85 per sq ft (total project savings exceeded
8 This associated cost savings resulted in an immediate payback that far exceeded expectations.
ccSPF XPS EPS PIR MineralWool
$4.84 $4.73 $4.59
(i.e. windo ws, expansion joints)
Seam (Sheathing) Tape Water/Air Barrier Insulation (R- 12)
CHART 1: Average Cost/sq.ft. of Insulation System (R- 12)