5 Must-Have Features in a Phenolic Foam Slab

26 • Interface August
REVIEW
Most are aware of the well-documented, less-than-desirable
characteristics of phenolic insulation when interfaced with structural
steel roof decking. Millions of square feet of existing roof systems
have been removed to facilitate steel deck remediation,
overlay, and in some instances, replacement, due to the corrosion
that has occurred because of the known acidic properties of the
insulation.
In recognition of the problem, the two manufacturers of the
product initiated class action settlements
to accommodate the anticipated flood of
claims. Due notice was provided through a
media blitz that included newspapers,
magazines, and television ads, educating
and advising building owners of the potential
problems associated with phenolic
products. Both manufacturers presented
case studies demonstrating the varied levels
of corrosion that could be expected.
They also offered economic data suggesting
that the financial burden of the costly
re-roofing should acknowledge depreciation
or useful life of the existing assembly.
Their efforts satisfied the court, and an
agreement or settlement class was derived.
Building owners who were fortunate enough to opt out of the
class put themselves at an advantage, such that they could potentially
improve their settlements beyond that offered within the class.
The settlement terms are clear in presentation as they relate to eligibility
requirements. These requirements are largely based on the type
and arrangement of roof system components in the assembly. For
example, phenolic-installed, direct-to-steel deck in either built-up or
single-ply configurations would be considered an eligible claim
(Photos 1 and 2). In contrast, the manufacturers have turned a blind
This article discusses recent findings suggesting that, in the presence of phenolic insulation, the integrity of structural
steel components such as shelf angles and brick ties may be compromised. The sampling and subsequent testing of
these materials has established a chemical link between the phenolic insulation and the observed volumetric expansion,
corrosion, and failure of these building envelope support mechanisms. As a result, costly wall repairs may sometimes
be required in conjunction with re-roofing. Also presented are the legal effects of these findings and the potential
recourse against the manufacturers of phenolic insulation that may still be available to building owners.
Photos 1 and 2 – A contrast in conditions
is apparent and can be expected when
phenolic insulation is installed over
structural steel decking.
eye to some steel deck installations
that incorporated a vapor retarder.
The presence of the vapor retarder
is cited as providing adequate protection
for the steel deck. Moreover,
specific to discussion in the body of
this paper, the settlement terms
state in part that, “the following
persons are not included in the settlement
classes:…(b) persons whose
roof system and roof deck are
entirely non-metal.”
It is widely accepted that, in
the presence of moisture, the corrosion
is decidedly worse. This
suggests that the moisture is the
vehicle or transport mechanism for
the acid from the insulation to the
underlying steel deck. Those familiar
with the phenomenon are quick
to recognize the broad spectrum
and wide variability of corrosion
that can be expected. A sharp contrast
of conditions, ranging from
severe rust to near pristine conditions,
has been observed adjacent
to one another in the field of the
roof (Photo 3). In most instances, the insulation installed in areas of
severe localized corrosion is laden with moisture. As would be
expected, the level of corrosion varies as the insulation component
moves toward its equilibrium moisture content, or that determined
by the service environment and ambient conditions.
The following discussion presents our observations and findings
made on two phenolic projects. The first project was initially considered
a routine, “within-the-class” claim with phenolic insulation
installed over steel deck, vapor retarder inclusive. The second project
began as a façade inspection required by municipal code.
PROJECT NO. 1
On a recent re-roofing project, driven by the presence of phenolic
insulation, it was noted that some above-roof sheet metal accessories
were exhibiting
varied levels of corrosion.
More specifically, galvanized
cap and counterflashing
(items not in
direct contact with the
offending material) were
corroding. These components
of the assembly
were installed in conjunction
with the built-up roof
system as part of the original
construction.
The measured interior relative
humidity of the manufacturing
facility was
62%, and the building was
pressurized. The roof system
consisted of the following
components from
the deck up:
August Interface • 27
Photo 3 – The protection offered by a vinyl vapor retarder at this inspection opening is questionable,
as the deck conditions presented no more than one foot apart ranged from near pristine to severely
corroded.
Roof deck: Fluted steel
Vapor retarder: Reinforced paper laminate
Base layer insulation: Mechanically fastened 1.7 in. phenolic
Top layer: 1/2 in. perlite mopped in asphalt
Membrane: Four-ply asphalt, fiberglass felts with
aggregate surfacing
Square footage: Approximately 300,000
Observations
The expansion joint wood blockings ran perpendicular to the
direction of the steel deck, centered over a 3/4-in. gap in the deck.
The sheet metal cap and counterflashing covering the expansion
joint were rusting. At the inspection opening, a wash of warm air
came out of the building, and condensation was noted on the vinyl
draped over the top of the wood blocking. The insulation adjacent
to the inspection opening was dry.
Another roof system feature was
the numerous curbs, installed as
part of the original construction,
intended to accommodate the owners’
needs relative to the predictable
changes in occupancy. These curbs
were wood framed and mechanically
attached to the deck. The steel
deck and vapor retarder were continuous
through the confines of the
curb, with the base and top layer of
insulation terminating at the outside
face of the curb. The curbs
were in-filled with fiberglass batt
insulation, covered with 3/4-in. plywood,
a single layer of plastic sheeting,
and a 24-gauge galvanized
metal cap (Figure 1). Severe corrosion was observed on the underside
of the sheet metal cap (Photo 4). Condensation was also noted
at these locations. The insulation around the curb was essentially
dry.
These observations suggest that movement of air through the
building envelope (more specifically, the steel deck flutes discharging
into deck openings at the expansion joint and curbs) may be a
sufficient avenue for the released acids from the adjacent, essentially
dry insulation. In this instance, the acids have migrated to
locations subject to condensation due to breaches in the roof system
components. This is supportive of the theory that essentially
dry phenolic insulation may contribute to the corrosion of steel in
contact with and close proximity to the offending materials. The
moisture content of phenolic insulation – that identified as the
transport mechanism for
the known acidic properties
of the material – need
not be in excess of equilibrium
or that established by
the service environment of
the installation.
It is worth mentioning
that the insulation manufacturer
dispatched its
claim specialist to this project
a number of years
before the owner decided to
move forward with the
remediation. Their expert
reportedly made one
inspection opening, witnessed
the presence of the
vapor retarder, and left the
project. The manufacturer’s
complacency worked
to the owner’s advantage in
successfully negotiating
more favorable settlement
terms.
Photo 4 – Excessive corrosion of sheet metal accessories (cap flashing) not in direct contact with phenolic
insulation. Free moisture, attributed to condensation, was present within the confines of the curb.
3/4” PLYWOOD
24 G.A. GALVANIZED CAP 4
COUNTERFLASHING
VAPER RETARDER
STEEL DECK
BATT INSULATION
PLASTIC SHEETING
FIBER CANT
4 PLY ASPHALT BUR
1/2” PERLITE MOPPED
IN ASPHALT
1.7” PHENOLIC
MECHANICALLY
FASTENED
Figure 1
28 • Interface August
PROJECT NO. 2
The author’s firm was retained to perform a critical
examination of façade components on a building in the
upper midwest. The structure was ten stories with the exterior
cladding consisting of a single wythe of brick tied to
CMU back-up wall. An insulated cavity wall was present. A
brick parapet wall extended approximately 3 ft. 6 in. above
the horizontal plane established by the poured concrete
roof deck. A series of limestone-clad, bay window assemblies
was present at regular intervals across each elevation
(Figure 2).
Observations
During the façade inspection, it became evident that the
brick veneer was exhibiting concentrated levels of distress
and out-of-plane conditions at the juncture of the roof deck
and outside face of the parapet wall (Photos 6 and 7).
Similar distress conditions were observed across the cutlimestone
cladding at the window heads (Photo 8).
A series of inspection openings in areas of localized distress
confirmed significant corrosion of the shelf angles
(Photos 9 and 10). The conditions were most prominent at
the tenth-floor roof slab and parapet interface, with conditions
improving at the juncture of the eighth-floor slab and
brick veneer (Figure 3). On the remaining similar floor slab
interfaces with the brick veneer, the deflection was present
but not as pronounced as that of the tenth floor. The subsequent
shift of loads from the upper limits of floors 10-8
was distributed to the remainder of the shelf angles
mechanically fastened to the outside face of the floor slabs
on floors 7-3. As a result, the integrity of the anchorage
mechanisms was compromised.
It was determined
that replacement of the
shelf angles and brick
veneer would be required
on floors 3-10.
Upon completion of the
façade inspection in the
fall of , a report was
issued in which the conditions
were described as
“safe with maintenance
and repair,” subject to repairs
by -04. Extending
the repair window
anything beyond the -
04 construction season
would have presented an
“unsafe and imminently
hazardous condition,” as
upwards of 60-70% section
loss had occurred at isolated
locations in the shelf
angles on the upper limits of the building.
As part of the design survey required to develop bidding documents
for subject wall repairs, it was determined that the roof construction
consisted of the following components from the deck up:
Roof deck: Poured concrete
Vapor retarder: Two-ply fiberglass set in asphalt
Base layer insulation: 1.2 in. phenolic
Top layer: 1/2-in. wood fiber
Membrane: Four-ply fiberglass in asphalt with
aggregate surfacing
Photo 5 – Wall system movement at the parapet/roof slab interface resulted in the meandering upper limits
of the balustrade capstones.
TOP OF PARAPET
CAP STONE
EXISTING
ROOF SLAB
WITH STEEL
SHELF ANGLE
TENTH FLOOR
SLAB
CRACKED LIMESTONE
CLADDING AT WINDOW
HEAD
OPEN MORTAR JOINTS
AND CRACKED BRICK
Figure 2
August Interface • 29
30 • Interface August
Given accelerated levels of corrosion observed on the shelf
angles at the roof slab interface, the discovery of phenolic insulation
as a component of the building envelope resulted in further
investigation. As a result, samples of corroded steel (rust pack) and
phenolic insulation were obtained from inspection openings at the
cut limestone clad window head of the tenth floor and at the shelf
angle mid-span, between the window bays. The samples were submitted
to a forensic lab for chemical analysis.
Samples of both the insulation and steel (rust pack) were
extracted in deionized water. Through Fourier Transform Infrared
(FTIR) Spectroscopy, used to analyze the extracts, it was determined
that the IR spectra were a match for para-toluene sulfonic
acid (PTSA). The measured pH of the extracts ranged from 3.5-3.8.
The results of the testing concluded that the presence of the PTSA
on the corroded steel and in the residues was a clear indicator that
the phenolic insulation contributed to corrosion of the steel. The
low pH and conductivity of the extract supports the findings that
acids were involved in the corrosion.
In contrast, a similar group of severely corroded steel samples
from window head lintels and fire escape connections was obtained
from a nearby building known not to include phenolic insulation as
a component of the roof assembly. This group of samples was subjected
to the same series of tests to determine if acids contributed
to the corrosion process. The measured pH of the extracts ranged
from 6 to 7 (basically neutral), with no evidence to suggest that
acids (more specifically PTSA), contributed to the corrosion.
Based on the above-mentioned lab results and the apparent
role of the phenolic insulation as a catalyst for the corrosion, leaving
the phenolic in place was considered an unacceptable risk. It
was determined that complete removal of the phenolic would be
required prior to introducing the new steel
shelf angles that would be necessary as
part of the wall repair contract.
A temporary roof covering consisting of
a torch-applied modified was specified. The
temporary roof included a four-foot band of
1/8-in.-per-ft. tapered material at the outside
parapet roof edge. This feature directed
water to the interior roof drains,
significantly reducing the likelihood that
water would be retained in the work area
soon to be occupied by the masonry contractor.
The removal of the existing roof provided
the opportunity to gather additional
information related to as-built conditions
of the roof assembly and its relationship to
the masonry features of the parapet. As
previously mentioned, there was a two-ply,
fiberglass vapor retarder mopped in
asphalt to the concrete deck. The felt plies
of the vapor retarder were turned up at the
parapet wall approximately 1.5-2.0 in. A
large quantity of the phenolic insulation
Photo 6 – Previous caulking repairs at open joints and cracks
of the brick in-fill between the window bays.
Photo 7 – At outside corners, the established horizontal
pattern of caulking repairs at open joints was supplemented
by additional vertical cracks.
was saturated, primarily to the north, south,
and east of the centrally located penthouse,
with moisture content in excess of 650% by dry
weight. That to the west of the penthouse was
essentially dry.
It could be argued that the vapor retarder,
installed over a concrete deck, would provide
adequate protection for any steel that might be
in close proximity to phenolic insulation, wet or
dry. However, on this project it was determined
that the portion of the vapor retarder that continued
through the transition from the horizontal
plane of the roof deck up the vertical surface
established by the interior of the parapet was
largely void of mopping asphalt.
The lack of mopping asphalt, in conjunction
with the porous fiberglass felts, results in a feltply
envelope in a critical location that is less
than watertight. It is at this location that the
soluble acids carried by the excess moisture
that could no longer be retained in the insulation
made its way into the wall cavity, resulting
in the accelerated corrosion of the shelf angles
(Photo 11). At no time since the roof was
installed has the owner reported disruption of
occupancy due to water leakage into the building interior, in spite
of the large quantities of wet insulation. Free moisture that could
no longer be retained in the saturated insulation moved laterally,
discharging into the wall cavity and making contact with structural
steel support mechanisms for the limestone cladding and brick
veneer (Photos 12, 13, and 14).
August Interface • 31
Photo 8 – Repetitive pattern of horizontal cracks across the
limestone-clad window heads. The distress conditions presented
were typical of the building’s four primary elevations.
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32 • Interface August
The results of this
investigation are supported
by sound mechanics
and the industry-accepted,
less-than-desirable performance
characteristics of
phenolic insulation in the
presence of moisture. As
such, the larger question
is, what happens beyond
discovery? Do these findings
challenge the terms,
conditions, and potentially,
the accepted limits of product
liability? Is there any
recourse for an owner of a
building currently exhibiting
wall distress conditions
that can be attributed to
the presence of phenolic
insulation? The following
discussion on legal issues will explore options that may be available
to building owners under current law.
LEGAL ISSUES
The History of Phenolic Foam Litigation
From through early , two companies manufactured,
distributed, and sold phenolic foam roof insulation to roofing
wholesalers, contractors, and property owners in the United States.
Beazer East, Inc., formerly known as Koppers Company, Inc.
(Beazer), manufactured, distributed, and sold phenolic foam roof
insulation from through January 17, . Schuller
International, Inc., now known as Johns Manville Corporation (JM),
manufactured, distributed, and sold phenolic foam roof insulation
from January 17, , through approximately March 31, .
From through early , Beazer or JM phenolic insulation
was installed on literally thousands of commercial, industrial, and
apartment buildings throughout the United States.
By the early s, some building owners who had installed
phenolic foam insulation over metal roof decks began to notice corrosion
problems on their metal decks. The costs of replacing the
roofing systems and repairing or replacing the supporting metal
decks were significant. Roof consultants and experts hired by the
building owners began to link the corrosion to the phenolic foam
insulation. However, early on, Beazer and JM often either denied
that the roof deck corrosion problem was caused by their phenolic
foam insulation or simply refused to adequately compensate the
owners for their repair or replacement costs. The inevitable lawsuits
against Beazer and JM followed.
The Phenolic Foam Class Action Lawsuit and
Settlement
In the mid s, some of these separate lawsuits were consolidated
by a Massachusetts federal judge into a single class action
captioned Sebago, Inc. and Flint Village, LLC v. Beazer East Inc.
f/k/a/ Koppers Company, Inc, Johns Manville Corporation, et al,
18 F.Supp.2d 70 (D.Mass. ). Interestingly enough, while the
original lawsuits that were consolidated contained many “state law”
claims against Beazer and JM for negligent representation, negligence,
strict products liability, fraud, and breach of implied and
express warranties, many of these claims were actually dismissed
or limited by the federal judge. The judge, however, did allow the
Photo 9 – A severely corroded shelf angle, and
subsequent rust jacking, was determined to be
the apparent cause for the out-of-plane
conditions observed at the brick in-fill between
the window bays.
Photo 10 – Volumetric expansion of the steel
shelf angles at the parapet/roof slab interface.
class action plaintiffs to proceed with their claims under a federal
statute known as the Racketeer Influenced and Corrupt
Organizations Act (“RICO”), based upon alleged mail or wire fraud
committed by Beazer and
JM in sending out “misleading”
brochures and
information.
In mid-June, , the
federal judge entered an
order granting preliminary approval of a proposed settlement.
Building owners who would otherwise be included in
the class for settlement purposes were given until
November 22, , to “opt out” and pursue claims on their
own. In mid-December, , the proposed settlement was
given final approval. For purposes of the settlement, the
class members were all persons or entities who had not
opted out and who, as of June 30, , owned an “Eligible
Property,” which was defined as a building on which the
phenolic insulation was installed over a metal roof deck and
within a built-up roofing system, a single-ply roofing system,
or a shingled roofing system. The class members, for
settlement purposes, did not include any building owners
who had installed phenolic foam over non-metal deck or
owners who had included phenolic foam within a metal roof
system whose exterior membrane was all metal.
Those who participated in the class action settlement
ended up signing global releases absolving Beazer and JM
from any liability whatsoever with respect to the phenolic
foam on their buildings. For example, in the Beazer settlement
agreement and release, the release language broadly
states:
Roof Owner does hereby release and forever discharge
Beazer… from any and all claims, liabilities, rights,
demands, suits, matters, obligations, damages, losses
or costs, actions or causes of action, of every kind and
description, in law or in equity, that the Roof Owner
has, had or may have against Beazer… whether known
or unknown, foreseen or unforeseen, accrued or which
may hereafter accrue, asserted or unasserted, latent or
patent, that is, has been, could reasonably have been or
in the future might reasonably be, asserted by the Roof
Owner against any Beazer party, either in this Action,
or in any other action or proceeding, in this Court or
Photo 11 – Apparent breach
in the two-ply vapor retarder
at the transition from the
horizontal plane of the roof
deck and adjacent wall. The
tear in the felt plies and gap
between the roof slab and
parapet wall are present
due to the corrosion of the
shelf angle, subsequent rust
jacking, and upward
movement of the wall
section. It is at these
locations that free moisture
carried water soluble acids
from the wet phenolic
insulation into the wall
cavity.
August Interface • 33
TYPICAL SECTION THROUGH PARAPET WALL
STRUCTURAL CONCRETE
1.0” INSULATION
CONT. L 5”X5”X5/16” SHELF
ANGLE
POURED CONCRETE
ROOF SLAB
COPPER COUNTER
FLASHING
TWO PLY VAPER
RETARDER
1/2” WOOD FIBER
1.2” PHENOLIC
INSULATION
AGGREGATE SURFACE
BUR
CANTILEVERED POURED
ROOF DECK EXTENDING
INTO WINDOW BAY
LIMESTONE CLAD WINDOW
BAY BEYOND
Figure 3
34 • Interface August
any other court or forum, regardless of the legal
theory, and regardless of the type or amount of
relief or damages claimed arising from or in any
way relating to the design, manufacture, distribution,
sale, handling, written or oral instructions,
specifications, marketing, use, performance or
any defects or alleged defects of Beazer, PFRI, and
any replacement, repair, treatment, remedial
work, removal or disposal of the Roofing System
or Deck at the Building, or any part thereof which
have accrued or will accrue as a result of having
Beazer PFRI on the Roof Owner’s Eligible Property
(“Settled Claim”)…
The form class action JM settlement agreement and release
contains similarly broad language.
Accordingly, building owners who settled with Beazer or JM
under the terms of the class action settlement are possibly barred
from bringing any claim for the new building envelope corrosion
phenomenon identified earlier in this paper. This is true even
though arguably the damage to the building envelope, as discussed
in the earlier portion of this paper, was not known at the time of the
settlement or even contemplated by any of the plaintiffs in the class
action. To be successful in any new legal action against Beazer or
JM, a building owner who already released claims pursuant to the
class action settlement would first have to prevail on an argument
that the class action settlement should be voided or reopened, or,
in spite of the express language of the signed release, that the settlement
and release did not cover damages for the new claims.
Claims Against Beazer or JM by Building
Owners Who Opted Out of the Class Action
or Who Were not Covered by the Class
Action
For the most part, building owners who opted out of
the class action, but who settled with Beazer or JM on
their own, signed settlement agreements and releases provided
by Beazer and JM that also contained very broad
release language, which arguably bars any new claims.
The only building owners who do not face the broad
release language problem are those who have yet to settle
any claims with Beazer or JM, either inside or outside the
class action lawsuit.
Applicable Statutes of Limitation and Repose
In addition to the release language issue, another hurdle
to a possible recovery against Beazer and JM for the
phenomenon discussed earlier in this paper is state law statutes of
limitation and repose. Many, if not most, states have statutes that
will bar a building owner from bringing a lawsuit for damage resulting
from negligent design, faulty construction, or defective materials
after a certain amount of time has passed. In Nevada, for
example, the applicable statute of limitations provides that any lawsuit
based on a construction defect must be commenced within
three years after the defect is discovered (NRS 11.190[3]). Further,
the Nevada statutes of repose provide that regardless of when (or
even if) the defect is discovered, any lawsuit based upon a patent
(or obvious) defect must be brought within six years after substantial
completion of the construction, and any lawsuit based upon a
latent (or hidden) defect must be brought within eight years after
substantial completion (NRS 11.204-205).
Most states have similar statutes of limitation or repose, although
the time periods will vary somewhat from state to state. In
Photo 12 – Relationship of segmented shelf angle providing
support for the limestone cladding, outside face of poured
concrete deck, phenolic insulation, and related roof system
components.
Photo 13 – Overall poor condition of cast-in-place receiver and anchor
bolt for shelf angles at outside face of poured concrete roof deck.
some states, claims otherwise time barred by an applicable statute
of limitation or repose will be allowed to proceed if the owner can
show fraud or fraudulent concealment on the part of the defendant.
The legal point is that even if claims against Beazer or JM have not
been expressly released in a settlement, they may be barred by the
applicable state statute of limitations and repose. Roofing contractors
and consultants who discover conditions with the building envelope
similar to those discussed in this paper should recommend
that the building owner immediately consult with a lawyer to determine
whether a timely claim could be brought.
THIRD PARTY ISSUES
Depending upon the severity of the problem, a building owner
who discovers conditions with the building envelope similar to
those described in the first sections of this paper may have to
immediately initiate costly repairs, whether or not there is a potential
recovery from the phenolic manufacturer(s) or others responsible
for the construction or design of the roofing system. A failure to
initiate repairs could result in significant additional damage to the
building in the future. Further, if portions of the building envelope
crumble or fall away, this could result in catastrophic loss or injury
to third parties, either in the form of third-party property damage,
injury, or death. If this were to occur in a situation where a building
owner knew or should have known about the problem but did
nothing, significant additional (and uninsured) liability could
attach. Roof consultants who continue to discover phenolic foam on
buildings should immediately alert their clients (in writing) to the
possibility of problems beyond the corrosion of metal roof decks.
Under certain conditions, it should also be recommended that
structural members that may have been exposed to the water soluble
acids known to be present in the phenolic insulation be inspected
as well.
SUMMARY
The findings of this investigation suggest that difficulties associated
with phenolic insulation may reach much further than that
accepted by the
industry and so
far acknowledged
and recognized
by the manufacturers.
The manufacturers
are
quick to discount
the claim, stating
they have never
heard of their product resulting in the described conditions/loss.
Lack of previous knowledge alone is not just cause to dismiss a
claim. With most product-related claims resulting in loss, there is
a discovery phase that is a precedent-setting, defining moment,
supported by fact that drives reaction to and acceptance of the phenomenon
as real.
The conditions described in this paper are driven by special circumstances
(high interior relative humidity, saturated insulation).
It is not being suggested that all buildings with phenolic insulation
will exhibit similar problems. However, the testing performed to
date indicates the release of para toluene sulfonic acid (PTSA) is a
continual process, supplemented by extreme service conditions.
The soluble acids are distributed to susceptible areas of the building
through the movement of free moisture and perhaps by moisture-
laden air moving across the building envelope to condense
elsewhere. The migration of acids through the building envelope
results in corrosion of steel elements that would typically be
thought of as not susceptible to damage. Buildings with concrete
decks and wall cavities are more likely to be subjected to damage,
as leakage to the building interior may not occur due to the monolithic
nature of the roof deck. ■
August Interface • 35
ABOUT THE AUTHORS
Photo 14 – Cracks
in the outisde
face of the
limestone
cladding were
caused by the
rust jacking of
both the
horizontal and
vertical legs of the
steel shelf angle.
Donald W. Kilpatrick has been
employed with INSPEC, Inc., since
. During his tenure in the laboratory
environment, he has evaluated
a broad range of roofing systems
and components, with an emphasis
on construction defects. Don’s
observations and analysis of these
components and assemblies has
been utilized in compliance and
workmanship testing on both new
and existing construction and failure
investigations. Most recently, he
has been assisting building owners with their specific needs
related to compliance with façade ordinance inspections.
Michael G. Taylor is a shareholder
and chair of the Construction Law
Group of Leonard, Street & Daimond,
Minneapolis, MN. He has extensive
experience negotiating engineering,
design, construction management,
and design/build contracts, and he
has represented architectural, engineering,
roof consultant, construction
manager, developer, owner and contractor
clients in construction-related
litigations, arbitrations, and
mediations throughout the country. Mike is active in the litigation
and construction insurance sections of the American Bar
Association. He has written and lectured extensively on various
construction, litigation, and insurance issues, and is an active
member of AIA, RCI, AGC, and ABC.
DONALD W.
KILPATRICK
MICHAEL G. TAYLOR

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High-density fiberglass batts for a 2 by 4-inch (51 by 102 millimeter [mm]) stud-framed wall has an R-15 value, compared to R-11 for "low density" types. A medium-density batt offers R-13 for the same thickness. High-density batts for a 2 by 6-inch (51 by 152 mm) frame wall offer R-21, and high-density batts for an 8.5-inch (216-mm) spaces yield about an R-30 value. R-38 batts for 12-inch (304-mm) spaces are also available.

Fiberglass insulation is made from molten glass that is spun or blown into fibers. Most manufacturers use up tp 40% to 60% recycled glass content. Loose-fill insulation must be applied using an insulation-blowing machine in either open-blow applications (such as attic spaces) or closed-cavity applications (such as those found inside existing walls or covered attic floors). Learn more about where to insulate.

One variation of fiberglass loose-fill insulation is the Blow-In-Blanket System® (BIBS). BIBS is blown in dry, and tests have shown that walls insulated with a BIBS system are significantly better filled than those insulated using other forms of fiberglass insulation such as batts because of the effective coverage obtained by this method of application.

The newer BIBS HP is an economical hybrid system that combines BIBS with spray polyurethane foam.

Cellulose insulation is made from recycled paper products, primarily newsprint, and has a very high recycled material content, generally 82% to 85%. The paper is first reduced to small pieces and then fiberized, creating a product that packs tightly into building cavities.

Manufacturers add the mineral borate, sometimes blended with the less costly ammonium sulfate, to ensure fire and insect resistance. Cellulose insulation, when installed at proper densities, cannot settle in a building cavity.

Cellulose insulation is used in both new and existing homes, as loose-fill in open attic installations and dense packed in building cavities such as walls and cathedral ceilings. In existing structures, installers remove a strip of exterior siding, usually about waist high; drill a row of three-inch holes, one into each stud bay, through the wall sheathing; insert a special filler tube to the top of the wall cavity; and blow the insulation into the building cavity, typically to a density of 1.5 to 3.5 lb. per cubic foot. When installation is complete, the holes are sealed with a plug and the siding is replaced and touched up if necessary to match the wall.

In new construction, cellulose can be either damp-sprayed or installed dry behind netting. When damp sprayed, a small amount of moisture is added at the spray nozzle tip, activating natural starches in the product, and causing it to adhere inside the cavity. Damp-sprayed cellulose is typically ready for wall covering within 24 hours of installation. Cellulose can also be blown dry into netting stapled over building cavities.

Polystyrene--a colorless, transparent thermoplastic--is commonly used to make foam board or beadboard insulation, concrete block insulation, and a type of loose-fill insulation consisting of small beads of polystyrene.

Molded expanded polystyrene (MEPS), commonly used for foam board insulation, is also available as small foam beads. These beads can be used as a pouring insulation for concrete blocks or other hollow wall cavities, but they are extremely lightweight, take a static electric charge very easily, and are notoriously difficult to control.

Other polystyrene insulation materials similar to MEPS are expanded polystyrene (EPS) and extruded polystyrene (XPS). EPS and XPS are both made from polystyrene, but EPS is composed of small plastic beads that are fused together and XPS begins as a molten material that is pressed out of a form into sheets. XPS is most commonly used as foam board insulation. EPS is commonly produced in blocks, which can easily be cut to form board insulation. Both EPS and XPS are often used as the insulation for structural insulating panels (SIPs) and insulating concrete forms (ICFs). Over time, the R-value of XPS insulation can drop as some of the low-conductivity gas escapes and air replaces it--a phenomenon is known as thermal drift or aging. 

The thermal resistance or R-value of polystyrene foam board depends on its density. Polystyrene loose-fill or bead insulation typically has a lower R-value compared to the foam board.

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Polyisocyanurate or polyiso is a thermosetting type of plastic, closed-cell foam that contains a low-conductivity, hydrochlorofluorocarbon-free gas in its cells.

Polyisocyanurate insulation is available as a liquid, sprayed foam, and rigid foam board. It can also be made into laminated insulation panels with a variety of facings. Foamed-in-place applications of polyisocyanurate insulation are usually cheaper than installing foam boards, and can perform better because the liquid foam molds itself to all of the surfaces.

Over time, the R-value of polyisocyanurate insulation can drop as some of the low-conductivity gas escapes and air replaces it -- a phenomenon is known as thermal drift or ageing. Experimental data indicates that most thermal drift occurs within the first two years after the insulation material is manufactured.

Foil and plastic facings on rigid polyisocyanurate foam panels can help slow down the aging process. Reflective foil, if installed correctly and facing an open air space, can also act as a radiant barrier. Depending upon the size and orientation of the air space, this can add another R-2 to the overall thermal resistance.

Some manufacturers use polyisocyanurate as the insulating material in structural insulated panels (SIPs). Foam board or liquid foam can be used to manufacture a SIP. Liquid foam can be injected between two wood skins under considerable pressure, and, when hardened, the foam produces a strong bond between the foam and the skins. Wall panels made of polyisocyanurate are typically 3.5 inches (89 mm) thick. Ceiling panels are up to 7.5 inches (190 mm) thick. These panels, although more expensive, are more fire and water vapor-diffusion resistant than EPS. They also insulate 30% to 40% better for given thickness.

Polyurethane is a thermoset foam insulation material that contains a low-conductivity gas in its cells. Polyurethane foam insulation is available in closed-cell and open-cell formulas. With closed-cell foam, the high-density cells are closed and filled with a gas that helps the foam expand to fill the spaces around it. Open-cell foam cells are not as dense and are filled with air, which gives the insulation a spongy texture and a lower R-value.

Like polyiso foam, the R-value of closed-cell polyurethane insulation can drop over time as some of the low-conductivity gas escapes and air replaces it in a phenomenon known as thermal drift or ageing. Most thermal drift occurs within the first two years after the insulation material is manufactured, after which the R-value remains unchanged unless the foam is damaged.

Foil and plastic facings on rigid polyurethane foam panels can help slow down thermal drift. Reflective foil, if installed correctly and facing an open air space, can also act as a radiant barrier. Depending upon the size and orientation of the air space, this can add another R-2 to the overall thermal resistance.

Polyurethane insulation is available as a liquid sprayed foam and rigid foam board. It can also be made into laminated insulation panels with a variety of facings. 

Sprayed or foamed-in-place applications of polyurethane insulation are usually cheaper than installing foam boards, and these applications usually perform better because the liquid foam molds itself to all of the surfaces. All closed-cell polyurethane foam insulation made today is produced with a non-HCFC (hydrochlorofluorocarbon) gas as the foaming agent.

Low-density, open-cell polyurethane foams use air as the blowing agent and have an R-value that doesn't change over time. These foams are similar to conventional polyurethane foams but are more flexible. Some low-density varieties use carbon dioxide (CO2) as the foaming agent.

Low-density foams are sprayed into open wall cavities and rapidly expand to seal and fill the cavity. Slow expanding foam is also available, which is intended for cavities in existing homes. The liquid foam expands very slowly, reducing the chance of damaging the wall from overexpansion. The foam is water vapor permeable, remains flexible, and is resistant to wicking of moisture. It can provide good air sealing, is fire resistant, and won't sustain a flame.

Soy-based, polyurethane liquid spray-foam products are also available. These products can be applied with the same equipment used for petroleum-based polyurethane foam products.

Some manufacturers use polyurethane as the insulating material in structural insulated panels (SIPs). Foam board or liquid foam can be used to manufacture a SIP. Liquid foam can be injected between two wood skins under considerable pressure, and, when hardened, the foam produces a strong bond between the foam and the skins. Wall panels made of polyurethane are typically 3.5 inches (89 mm) thick. Ceiling panels are up to 7.5 inches (190 mm) thick. These panels, although more expensive, are more fire and water vapor-diffusion resistant than EPS. They also insulate 30% to 40% better for given thickness.

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