"The common law of business balance prohibits
paying a little and getting a lot. It can’t be done. If you deal with the
lowest bidder, it is well to add something for the risk you run, and if you
do that you will have enough to pay for something better."
-John Ruskin 1819-1900
Caulk in Large Joints Can't Handle
Bond-Line Tensile Stresses:
stresses at the bond line and within the body of the sealant cause
COLORSEAL: Tensionless Movement,
Watertight, Aesthetic, Insulates:
(Click image to enlarge)
An old product is being marketed with renewed vigor. It is being
presented as a
equal in performance to EMSEAL's pre-compressed, hybrid,
silicone-and-impregnated-foam sealant (COLORSEAL) at a fraction of the cost.
Given the adage "if it sounds too good to be true, it probably is," the
following provides a basis on which to understand the fundamental
differences between these technologies and how this material is by no means
an equal to COLORSEAL.
see how this plays out in the field on a project where this material has
failed and been repaired with COLORSEAL, see the
Buffalo Thunder project profile.
purposes of description, we are comparing COLORSEAL to a "pre-cured,
caulk-and-backerblock" material. It looks like this:
Old For New
This product concept was introduced in the '80's by a company called
Williams Products. It never gained much traction in the commercial
construction market but now has been picked up by other expansion joint
products companies and is being sold by them as something new.
Tensionless Sealant Systems
The development of the COLORSEAL products is based on the fact that liquid
sealants in large movement joints do not function because tensile stresses
at the bond line and within the body of the sealant cause bond-fatigue over
time and ultimately result in adhesive or cohesive failure of the sealant.
COLORSEAL overcomes this shortcoming through
the application and factory-curing of a silicone sealant over a preformed,
impregnated foam backing at a width nearly twice that of the intended
joint-gap size. This wider-than-joint-size sealant is gathered into
bellows during compression of the product to less than the joint-gap size.
After installation into the joint, the silicone bellows simply folds and
unfolds during movement--free of tensile stresses. The addition of a
corner-bead of silicone is purely a redundant step in ensuring the bond of
the silicone bellows to the substrate. EMSEAL’S
COLORSEAL is watertight at the silicone face as well as watertight at the
foam secondary sealant level.
sealant is gathered into bellows during compression of the product to
less than the joint-gap size."
silicone bellows simply folds and unfolds during movement--free of
The Weakest Way to Use an Adhesive:
does have a pre-cured bead of sealant, however, this bead is formed to
less than the joint-gap size. It relies as a result on the field-applied
silicone to adhere the pre-cured caulk to the substrate.
is a well known fact of engineering that adhesives are weakest in tension.
This means that the field-installed sealant adhesive required to attach the
pre-cured caulk bead to the substrates, as well as the pre-cured caulk bead,
will be put into tension as the joint opens. Consequently,
there is no difference in performance between using caulk and backerod and
bead is formed to less than the
field-installed sealant adhesive required to attach the pre-cured caulk
bead to the substrates, as well as the pre-cured caulk bead, will be put
into tension as the joint opens."
product is not pre-compressed and relies on the field installation of
sealant to attach the undersized preformed bead to the substrate. As
movement occurs at the joint-gap the sealant is put into tension and is
therefore susceptible to bond-fatigue failure as well as cohesive failure of
the sealant bead. Furthermore, installation in this manner adds two
new bond lines to the system multiplying the potential for bond-line
system prescribes a 3/8" x 1/2" adhesive sealant bead. Given the
likelihood that the joint-gap into which the sealant is being installed will
vary in size from the base of the building to the roofline, it is improbable
that this adhesive mass will be regularly achieved. Consequently the
presence of sufficient adhesive to withstand likely tensile stresses will be
Precompressed vs. Forced In Place
polyurethane/polyester backer block used in the
is not pre-compressed – it is a “force compressive joint” (squeezed by hand
and shoved in), nor is it impregnated with any waterproofing additives.
Like backerod in conventional caulk-and-backerod installations, the
backer-block of foam performs no function other than to support the caulk
bead during installation. If the sealant on the
is breached the foam by itself is not watertight and will actually
EMSEAL's COLORSEAL features
an impregnated open cell foam which is pre-compressed at the factory
to less than the joint opening and, once released from compression
constraint at installation, is designed to push against the substrate with 1
½ to 2 lbs per square inch of back pressure.
water-based, stabilized, polymer-modified acrylic adhesive impregnated
foam of COLORSEAL is water tight without the addition of silicone and
therefore provides real belt-and-suspenders sealing in a single material
Testing--The Final Proof
An understanding of the principles of performance of the two systems should
be sufficient to demonstrate the considerable differences in composition as
well as performance. In addition, however, COLORSEAL by EMSEAL has
endured rigorous independent performance testing and passed all three of the
following performance tests usually reserved for evaluating curtain wall
systems. After all, shouldn't the sealant system used in the wall meet
the same standards applied to the components of that wall?
of Air Leakage Through Curtain Walls
Penetration of Curtain walls due to Uniform Static Air Pressure
Difference (with and without punctured and damaged primary seal surface)
Structural Performance of Curtain Walls under Uniform air Pressure
Difference (Gust Loads)
Watertightness, ability to handle expected movements, durability, and
aesthetics are reasonable standard performance expectations of an expansion
joint sealant. In addition, with today's emphasis on energy
efficiency, having your expansion joint sealant insulate an often overlooked
thermal breach is an added benefit. COLORSEAL provides 2.94 R value
per inch of depth making it unique in its ability to contribute to your
buildings climatic stability.
On this basis, the
product is by no means equal in design or performance to the
hybrid, silicone-and-impregnated-foam sealant
always when conducting a comparison of two materials,
Request a sample
to compare composition and performance claims of the contenders.
this age of conglomerations, buyouts, consolidations and spin-offs, the
commoditization of specialty products is a likely result. There do
remain a few suppliers whose integrity remains tied to that of their
owner/founders. That is not to say that these are the only reliable
sources of lasting joint sealing solutions but a healthy skepticism of bold
claims, rapid changes, and old technology revivals will serve your clients well.
Thank you for your consideration and continued support of EMSEAL's products.
As we move forward, one satisfied building owner at a time, we find
validation in our approach and in the words of a nineteenth century
observer of society and the construction arts, John Ruskin:
“It is unwise to pay too much, but it’s worse
to pay too little. When you pay too much you lose a little money—that is
all. When you pay too little you sometimes lose everything, because the
thing you bought was incapable of doing the things it was bought to do. The
common law of business balance prohibits paying a little and getting a lot.
It can’t be done. If you deal with the lowest bidder, it is well to add
something for the risk you run, and if you do that you will have enough to
pay for something better.”
To give us feedback on this or any other
topic on our website please feel free to call 508-836-0280.