Watertight Expansion Joints and Construction Sealants by EMSEAL

SJS-FP System

Seismic Joint System For Plaza Decks & Split Slabs

A seismic plaza deck expansion joint system the SJS-FP System is designed to provide a watertight, trafficable joint system in wide expansion joints in hardscaped decks of split-slab design. SJS-FP expands the use of the SJS System to waterproofed hardscaped split-slab deck designs through the use of structural-slab mounted retainer legs with integral waterproofing side sheets that integrate with the deck waterproofing membrane.

The retainer legs are available in leg heights that can be matched to the topping slab or wear course thickness. The waterproofing side sheets lock into the top of the retainer legs and are embedded in and encapsulated by the deck waterproofing membrane. The SJS System foam/spline assembly installs between the faces of the retainer legs. The foam/spline assembly is constructed from two precompressed foam sealants pre-assembled in parallel adjacent to a heavy-duty extruded aluminum spline. The spline acts as a receptor for attaching the surface-mounted traffic plates that bear vehicle and other loads.

The result is a system that is watertight and covered with a cover plate that is securely anchored into the wear course.

SJS-FP System

Seismic Joint System For Plaza Decks & Split Slabs


  • Watertight & traffic durable
  • ADA Compliant
  • Watertight and static tie-in to deck waterproofing
  • Sound dampened
  • Non-invasive cover plate anchors


Straddles structural joint-gaps 1″ (25mm) and greater. Minimum joint gap between SJS-FP angles is 2″ (50mm)


100% Total (+50% and -50% of nominal supplied size.)


  • Standard cover plate is aluminum with ADA-compliant, sand-blasted finish. Stainless steel also available.
  • Other finishes by request (contact EMSEAL)


  • Split-slab decks with concrete, paver or asphalt hardscaped wear courses
  • Parking decks
  • Plaza decks
  • Podium decks
  • Airport roadways
  • Mall bridge connectors
  • Stadium concourses, etc.
  • For new construction, as well as repair and retrofit of old or failed expansion joint systems.
  • For restoring watertightness to chronic leaking over occupied spaces.
  • Uniquely suited to joint openings designed for seismic separation of structural building elements.

Watertight – Emseal FP (For Plaza) systems are purpose-designed to provide watertight joint sealing and watertight integration with the buried deck waterproofing membrane. The DSM System material is installed between the faces of the FP retainer legs with the silicone bellows facing the weather to ensure watertightness in the joint gap. The tensionless silicone bellows are installed essentially flush to the deck surface just below the stainless steel capping strips thereby ensuring watertightness at the wear-course surface. This eliminates the need for secondary moisture barriers and gutter systems.

Sound Attenuation – The flanking impregnated foam and silicone hybrid dampens sound and shock effectively. When installed over EMSEAL-supplied elastomeric nosing material, the result is arguably the quietest watertight coverplate system available.

Self-Locating Coverplate Screws – The center spline is a continuous receptor for the coverplate screws that are self-tapped into the anchor channel. This dramatically reduces the installation-related problems of locating self-centering, sliding ball devices and pantographs. The probability of screws being left out is eliminated ensuring proper anchoring.

Self-Locking, Vibration-Dampened Screws – Vibration in systems that rely on metal-to-metal connections and contact points is the main cause of screw loosening. SJS by EMSEAL minimizes vibration through the dampening action of the massive and continuous springs of impregnated foam along the entire length of the joint. In addition, 30 pounds of force is required to loosen the screws offering excellent screw tightness without the need for thread-lock compounds.

Field-Adjustable Plate Support – Concrete in new and retrofit applications is inevitably uneven across and along the joint. The SJS can be installed over a leveling-bed of EMSEAL-supplied Emcrete elastomeric nosing material. This provides the ability to fine-tune the support of coverplate sections reducing rocking and noise caused by unleveled plates. Systems that attach or utilize intrusive extruded rails to receive sliding ball and socket devices cannot be adjusted to eliminate unevenness across and down the length of the joint.

Continuity of Seal – All EMSEAL expansion joint systems feature continuity of seal through changes in plane and direction –– an essential performance differentiator. Fabricated transitions from deck to wall, at curbs, sidewalks, parapets, tees, and crosses are available with the SJS.

Finite Element Analysis (FEA) Compiled Safety Factors – Prior to field trials, the SJS by EMSEAL was modeled using FEA to determine the suitability of design to worst case possible parking deck loads. Under the scenario of a 4,000 lb vehicle skidding across the joint system to full stop once past the coverplate, FEA modeling predicted lateral displacement of the coverplate of less than 3/4-inches (19mm) and safety factors in key components as follows:

FEA Safety Factors:
Traffic Plate – 5; Screws – 11; Spline Pins – 10; Center Spline – 7

  • The system consists of two subassemblies:
    1. The structural-slab mounted supporting legs with integral waterproofing side sheets
    2. the joint sealing and coverplate assembly
  • The mounting leg assembly is delivered with opposing legs factory-set to the nominal joint size. It is installed into a wet-setting bed of epoxy mortar and bolted to the deck.
  • The joint sealing and bridging assembly consists of a central stiffening spline flanked by two watertight silicone bellows supported by precompressed, impregnated foam shock absorbers, and covered by a heavy duty coverplate.
  • The factory-assembled spline, bellows, foam, are shipped with factory attached, installation hanger-bars.
  • Epoxy gel adhesive is applied to the faces of the previously installed mounting leg assembly.
  • The sealing assembly is lowered into the joint gap where it self expands into the wet epoxy adhesive.
  • Consecutive lengths are joined through the field-application of manufacturer-supplied, low-modulus, high-movement silicone to the spline and intersecting bellows surfaces. Friction fit alignment pins prevent the joins from moving during silicone cure.
  • A field-applied silicone sealant band is injected at the bellows to joint substrate interface to complete the waterproofing.
  • The deck waterproofing membrane is installed on the deck and brought up to the SJS-FP System. With the SJS-FP side flashing sheets pulled out of the way, the membrane is installed over the top of, and up the SJS-FP mounting legs. The side flashing sheets are lowered into the liquid membrane (or into the non sag mastic component of a sheet waterproofing system) and sandwiched with another layer of waterproofing.
  • Concrete, pavers, asphalt, or other topping slab or wearing course material is installed up to the stainless steel retaining caps on the SJS-FP mounting rails.
  • The SJS-FP joint-sealing assembly installation hanger bars are removed sequentially as coverplates are lowered over the joint and screwed to the center spline, completing the installation.The basis of the SJS-FP System is SJS System which is comprised of silicone-and-impregnated-foam hybrid components that ensure watertightness, absorb sound, dampen vibration and offer uncomplicated installation. Created from the latest evolution in the field-proven technology that EMSEAL has used for 30 years of sealing horizontal plane joints with impregnated foam sealants, the SJS System is constructed from two horizontal joints pre-assembled in parallel adjacent to a heavy-duty extruded aluminum spline. The spline acts as a receptor for attaching the surface-mounted traffic plates that bear vehicle and other loads. The result is a system that offers features and benefits not found in alternative products intended for large horizontal structural joint gaps.

Joint Sizes: Because SJS-FP installs into its own legs, the legs can straddle mean-temperature, structural slab, joint sizes from: 1-inch (25mm) up to 24-inches (600mm). The minimum gap between the SJS-FP legs is 4-inches (100mm).

Leg Heights: 4-inches (100mm) to 12-inches (300mm)

Depth of Seal (Foam Depth):
4-inches (100mm) to 8-inches (200mm) wide = 4-inch (100mm) deep
9-inches (225mm) to 18-inches (450mm) wide = 5-inch (125mm) deep


  • Standard coverplate is 3/8-inch (10mm) shot-blasted aluminum or Type 304 stainless steel. Other custom metals are possible–consult EMSEAL.
  • Coverplate thicknesses can be customized to suit load and traffic expectations-Consult EMSEAL.


  • As with any construction product, the useful life of the material can be maximized with routine inspection and repair if required.
  • Clearing of surface debris and inspection will reveal any damage to the product or adjacent substrates that might affect building performance.
  • Repair, if necessary of the system can be accomplished by removing the cover plates and without removing the FP capping strips–requiring only damaged sections of the foam-and-spline-assembly to be removed and reinstalled–not the entire length of the joint as is typical of extruded-seal systems. Consult EMSEAL to discuss specific conditions.
  • In installations subject to snow removal, the detail for recessing the system to flush with the deck should be used. Consult EMSEAL. For guidance on appropriate snow removal practice click here.
  • Available for shipment internationally.
  • Prices are available from local distributors or representatives and/or directly from the manufacturer.
  • The product range is continually being updated, and accordingly EMSEAL® reserves the right to modify or withdraw any product without prior notice.