"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:
COLORSEAL: Tensionless Movement,
Watertight, Aesthetic, Insulates:
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.
To 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.
For purposes of description, we are comparing COLORSEAL to a "pre-cured, caulk-and-backerblock" material. It looks like this:
Old For New
Tensionless Sealant Systems
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.
The Weakest Way to Use an Adhesive:
It 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 "pre-cured, caulk-and-backerblock".
The 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 failures.
The 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 unlikely.
Precompressed vs. Forced In Place
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 ˝ to 2 lbs per square inch of back pressure.
The 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 installation.
Testing--The Final Proof
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.
As always when conducting a comparison of two materials, Request a sample to compare composition and performance claims of the contenders.
In 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:
To give us feedback on this or any other topic on our website please feel free to call 508-836-0280.
Expansion joints and
sealants by EMSEAL
Last Modified: March 10, 2014