Boss SpineSeal – A new expansion and control joint seal

Boss SpineSealA unique expansion and control joint seal system for gaps in vertical, horizontal and overhead structures is delivering fast installation times, high performance weather and sound insulation, and reduced environmental and OH&S impact.

The key to the Boss Polymer Technologies SpineSeal design is an extruded rubber fin shaped seal, which is folded over a rigid backbone and then driven into the gap. The rigid polymer backbone forces the SpineSeal into the gap and the “fins” on the rubber seal provide several layers of weather and sound barriers. In addition, a range of architectural exterior finishes and colours can be compounded and permanently moulded into the SpineSeal. This allows the architect or designer to tailor the seal design and its exterior appearance to suit the application.

This new product is the result of innovative development work invested by Boss with collaboration from the sound barrier engineers at Thiess John Holland, contractors on the EastLink freeway project connecting Melbourne’s eastern and south eastern suburbs. One of the largest road construction projects in the world, this 45 kilometre freeway features state of the art safety and environmental elements, including a range of purpose built sound barriers.

Gasket contract leads to SpineSeal

Initially, Boss won the tender to supply Thiess John Holland 50,000m of UV resistant EPDM rubber gaskets for the 7500 brightly coloured acrylic sound panels rising over the hills and bridges of the freeway. Then Boss was introduced to the bigger challenge of providing a 30-plus year weather resistant seal that could be installed quickly, cleanly, and in any weather for the thousands of huge, cantilevered concrete sound barrier panels to be installed on both sides of the roadway for much of the freeway’s length.

To win the contract for this seal system from the traditional caulking materials and common compression seals, Boss became the polymer engineering partner on the sound barrier project.

The Boss engineering solution delivered real benefits, including:

  • Easy application – light weight SpineSeal is easily installed by one man working from a boom lift using simple mallet and press hand tools to ensure perfect fit with no variations.
  • Fast installation – each seal is installed uniformly in a single piece in minutes in any weather conditions.
  • Clean and safe installation – improves OH&S and environmental performance by eliminating adhesives, chemicals, caulking, and their dirty containers and messy clean up.
  • No preparatory work – the SpineSeal design allows for a wide range of variations in:
    • The manufacture of the concrete panel (rough gap edge surface condition).
    • Panel installation gap widths (ranging from 5mm to 80mm on the EastLink project).
  • Excellent sound and weather insulation – each “fin” in the SpineSeal provides an extra layer of air lock and sound barrier.
  • Flexibility and retainability – the SpineSeal adjusts to gap variations caused by expansion, contraction or subsidence of the concrete panels, while remaining locked in place due to the multiple fins on either side of the rigid backbone.
  • Long life – the elastomer can be engineered specifically for the climatic exposure predicted for each application, including high UV levels, moist or dry conditions.
  • Aesthetically appealing – the elastomer can be engineered in any colour required to match / contrast with the concrete panel, and surface designs can be applied.
  • Non-skilled labour can install SpineSeal following a simple, short training session.
  • Boss SpineSeal is OH&S and environmentally friendly to manufacture and to install on site.
  • Quality Control – the SpineSeal design and ease of installation allows for easy pre and post installation quality control auditing.

Boss SpineSeal cuts costs

Compared to the traditional joint backing rod and caulking method, which requires experienced labour working in good weather conditions to build up layers of caulking compound in wide and uneven gaps in a vertical plane, the Boss SpineSeal proved an economical solution. On the EastLink project, it was up to two times faster to install and was fitted in all but the very worst weather conditions.

Thiess John Holland Noise Barrier Manager, Paul Belcourt said that previously precast concrete barriers were jointed with traditional caulking materials. The Boss SpineSeal solution was achieved through collaborative work by the Thiess John Holland engineers and the Boss Polymer Technologies team. “The enthusiasm and dedication of the Boss product development team helped to achieve acceptance of the concept. The SpineSeal proved to be more effective than caulking, especially in the wider gaps. SpineSeal can be installed even if panels are wet. Quicker installation meant money saved,” he said.

The key to the success of this new seal technology on the EastLink project was speed of installation. Thiess John Holland Project Engineer Frank Kose said that productivity up to 200 lineal metres of seal installed in nine working hours was achieved with a two man crew. “Using the SpineSeal, we minimised general construction rubbish on site, such as plastic caulking tubes. The Boss product is user friendly and less messy for the applicators to use. It adapts to the gaps size and shape and its consistent nature minimises seal quality issues. We have certainty that once installed, it satisfies design requirements and that simplifies quality control,” said Frank Kose.

Boss Polymer Technologies Managing Director Norman Mills said the SpineSeal can be extruded in a wide range of polymers to tailor the performance and aesthetic requirements to each application. “The ELASTOSIL R® silicone rubber used in the EastLink application is UV, heat, ozone and weathering resistant, and was proven in industrial tests, including climate DIN50018-SW2.0S and ozone DIN53509-1. Even after 30 years or more exposure, there is virtually no change in the properties of the silicone seal,” he said.

International patents are pending for the Boss SpineSeal technology. In addition to the initial application of the Boss SpineSeal in concrete panels, Norman Mills envisages a wide range of applications for the product in the construction of roads and commercial buildings, including filling gaps in overhead panels, which are difficult and costly to seal with traditional methods.