November 14, 2019

Advances in foam tape technology seal offsite construction

Foam sealing tapes can drive faster installation and improve energy efficiency, says Andy Swift of ISO Chemie, sales and operations manager – UK & ROI, ISO Chemie, who considers their use in offsite modular construction.


Despite wider construction sector struggles to deliver projects on time in the face of escalating costs, falling levels of customer satisfaction and wider economic uncertainty around Brexit, we have seen a surge in offsite modular construction, disrupting the construction industry in a positive way and shortening the time between project conception and completion. For example, the UK has witnessed a steady rise in off-site construction methods*. Demand from the market is also encouraging councils to open-up their doors to modular. Indeed, the market for prefabricated modular buildings and portable accommodation is estimated to have increased by 6% in 2017 – a significant improvement from 2016.

While modular will shorten build times and cut costs, it also leads to an improvement in safety, reduces wastage and protects against external elements such as the great British weather. Also, in the face of skilled labour shortages, the approach has the potential to reduce dependence on a manual skill-base by moving to a leaner manufacturing process.

In offsite construction, systems are delivered to site pre-assembled and pre-tested with guaranteed built-in quality and reduced installation times. The approach allows contractors to undertake smart engineering and co-ordination at the front end of a project, avoiding the problems often associated with putting fitted together systems on a construction site, leaving behind a legacy of a quality installation that can be easily maintained throughout its whole life cycle.

Companies like ISO Chemie, which provides foam and other tapes solutions for the high-performance sealing of windows, doors, construction joint gaps and facades, are working with other building products suppliers to develop integrated solutions, which meet the demands of offsite construction and deliver supply chain added value.

Faster installation

One such is Smartroof, whose panelised roof system provides advantages in terms of faster installation times when compared to traditional roof construction techniques, particularly for new build town houses. The system is factory insulated to the client’s specification and the party wall panels and the block work airtight, acoustic and thermally sealed, while accommodating potential differential movement between the two surfaces before shipping to site and final installation, using ISO-Chemie’s tape. The tapes that have featured in projects are an integral feature of Smartroof’s offsite construction activities, specified due their high performance and reliable performance.

Another offsite innovator is Modcell, whose cassette-style prefabricated system utilises the excellent thermal insulation qualities of straw bale and hemp construction to form prefabricated panels. These can allow super-insulated, low energy ‘passive’ buildings to be constructed using renewable, locally sourced, carbon sequestering materials, ensuring that buildings can be constructed to meet the demanding PassivHaus specification, with resultant almost zero heat requirements, saving money and CO2 emissions.

The firm has used foam tapes in several projects to provide airtight, acoustic and thermal interior and exterior seals between prefabricated panels, which are then used in offsite construction.

Sustainability was a key driver for the project: ModCell panels were used to build the super-insulated structure to the highest ecological standards using thermally efficient, 48cm thick, prefabricated straw bale wall panels, with tapes filling the 10mm expansion joints between panels and around windows and doors. This helped to achieve an excellent target of <2.0 m³/hour/m² measured at 50 Pascals air tight seal for the complete building – a good standard for the construction industry is anything between 3 – 5 m³/hour/m².

Another beneficiary of tape technology is the Spinelock Group, which specialises in manufacturing extruded aluminium framed housing sections that are constructed off-site and feature insulation, rainwater harvesting, and renewable energy systems already incorporated into the design. The Mansfield-based firm has used the ISO BLOCO One to provide an airtight sealing solution for its advanced structural floor, walls and roofing system, used in the construction of zero carbon emissions homes (A+ Energy Performance) – specifically sealing the gap between pre-engineered openings for doors and window systems to be compliant with full air tests.

Tapes such as ISO-BLOCO One and others offer a single product ‘fit and forget’ solution for fast and effective sealing based around the European RAL principles of three level sealing – the inside seal area is more airtight than the external one, allowing any trapped moisture inside the joint, or within the wall, to escape outwards rather than into the building.

The external seal area provides weather resistance and breathability with a minimum resistance of 1000 Pascals (hurricane forces), while the intermediate seal area provides extra thermal and acoustic properties, with a U-value between 0.55 and 0.8 subject to tape size, and the internal one air tightness and humidity regulation, the tape installation itself gives less than 0.01 m³ air loss when tested at 1,000 Pascals air pressure difference. All three levels are designed to accommodate movement between the adjacent materials.

Significant strides

Significant strides have also been made in reducing on-site window and door system installation times through the introduction of offsite construction techniques. Here, one company at the forefront is Sidey with its KitFix System, which adds value to timber frames and structural insulated panel systems (SIPS) while delivering significant benefits to contractors and, ultimately, customers looking for supply chain savings.

This system enables fully glazed windows and doors to be installed into timber frame and SIPS panels as part of the offsite production cycle, while having little impact on stacking, transportation and erection of the finished panels. ISO-CHEMIE’s ISO-CONNECT Vario SD humidity regulating foil, which offers ‘intelligent’ humidity control and complies with UK Building Regulations for air when used as an internal seal, offers Sidey’s system effective weather and air tightness sealing of the window and door frame connecting joints, facilitating faster onsite build.

Foam sealants provide superior moisture resistance together with air tightness and thermal insulation for timber-framed buildings, undoubtedly aiding product suppliers in the drive towards more sustainable, faster offsite construction. But equally important, with the careful management of all manufacturing logistics and sequencing, they contribute effectively to eliminating potential waste, risk and cost in the supply chain without compromising offsite construction quality.

Andy Swift, ISO Chemie

* https://www.amaresearch.co.uk/uk-market-for-volumetric-modular-buildings-increased-by-6-in-2017/