Filling the Gap: ZB & ZBSM


Welcome to our first installment of “Filling the Gap,” a new series dedicated to educating you about expansion joint solutions. For this inaugural post, we’re going to explain what makes our ZB and ZBSM expansion joint systems excellent choices for parking deck applications. (Hint: no elastomeric concrete.)

First, a bit of background information. Zip Block® (ZB) is a waterproof, one-piece, extruded EPDM elastomeric seal with integral nosings. It is easily installed in four steps using high-strength epoxy to bond to the substrate and self-leveling edge sealant, eliminating the need for messy elastomeric concrete. ZBSM offers the same features as ZB but is surface mounted with ADA-compliant wings. Both versions result in a watertight system that is so durable it will last for the entire lifetime of the parking deck.

Filling the Gap ZB ZBSM CS Blog

How do we know it’s durable? Rigorous testing, including rolling loads of 3,000 lbs., with simultaneous vertical slab deflection; sub-zero temperature testing, including several freeze-thaw cycles, and all applicable ASTM cycling tests. At 35,000 cycles, the seal exhibited no wear or tear from the rolling load.

Traditional winged seals with elastomeric concrete fail regularly due to wheeled impact causing hairline cracks in typical applications. Through further wheeled impact, cracking becomes more severe until the seal’s wing pulls away, allowing water penetration. Additionally, elastomeric concrete wing joints require a 12+ step installation process that includes mixing and pouring multi-part elastomeric concrete and a precise amount of hardener accelerator aggregate. If the mixture is too dry or too wet, performance issues arise.

Filling the Gap ZB ZBSM CS Blog

As you can imagine, installing ZB is significantly easier and it takes about 30% less time than elastomeric concrete wing joints, meaning your labor costs will be reduced. We think it’s a no-brainer, but don’t just take our word for it—here is what our representative Jim Baker in Indiana has to say about the ZB series:

     When I first joined Construction Specialties as their rep, I was very impressed with the ZB joint. I had been a rep for a competing manufacturer for many years that had the traditional wing joint       with and without mechanical fastening. From personal experience with installing traditional wing joints, the ZB joint is 100% a better choice.     

     Let me reassure you that the ZB joint will outlive any traditional wing joint on the market today. Many garages in my territory have had ZB joints installed in them for well over 15 years.

    The full bed of epoxy both under the wings and down the vertical sides of the joint throat in addition to the edge joint sealant provides three different ways to stop water from getting in.

    The single-piece construction improves the impact resistance of the joint. To date, there has not been one failure due to durability or movement issues with projects in my territory.


Wow. We couldn’t have said it better ourselves. And don’t fret if you already have elastomeric concrete wing joints in place—when they inevitably become damaged, you can easily replace them by removing the old seal, applying epoxy, and “walking in” the ZB seal.

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ADS Life Cycle Cost Analysis

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