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RCI January 2018

PITCHED ROOFING Sealants in joints in building façades the different things that contractors should be considering when choosing a sealant for their building façade Regardless of the method of Marc Rampling, technical services manager of Hodgson Sealants discusses construction, the sealing of interfaces between materials, and the joints they create, is critical both from an aesthetic and performance perspective. Therefore, it is essential that you select a suitable sealant product for your building project. Joint movement is caused by numerous internal and external factors. Failing to use an appropriate sealant in your building’s joints can lead to a breadth of issues and complications, including reduced building performance. However, there are a wide variety of materials in common use to compensate for such problems. What must be considered when choosing a sealant? When selecting a sealant for the joints in your building’s façade, there are a number of areas that you must carefully consider. The sealant must be compatible with adjacent materials and suitably adhesive to a variety of substrates, therefore taking the full building façade into account. You must address the sealant’s durability and the ways in which its physical property may change after exposure to the elements; in turn, this requires you to consider sealant movement capability. Finally, the effect of the sealant on your building’s appearance is also crucial when considering the project as a whole. What are the advantages and disadvantages of cartridge-applied materials? Cartridge-applied materials have been used as a 078 JANUARY 2018 RCIMAG.COM joint sealant for many years, and are still as relevant today. They are easy to apply to preconstructed joints, and allow you to adjust the depth of seal required to cope with building tolerances. Traditionally, the two primary options for a onepart moisture curing were silicone or polyurethane technologies. However, whilst each has numerous strengths, they also have inherent weaknesses, as illustrated in the table. Whilst the technology surrounding hybrid sealants has been around for a number of years, the latest generation of materials offers additional benefits that earlier materials could not match. As shown in the table, the mature hybrid technologies have the same benefits as the silicone and polyurethanes; however, they are without many of the disadvantages. Why consider a Hy-Spec hybrid sealant? Despite the table showing the increased benefits offered by a typical hybrid sealant, not all of the properties are ideal. Early formulations were slow to cure, gave poor resistance to water immersion, and suffered from yellowing. To solve these common problems, Hodgson Sealants used their 50 years’ experience supplying to the construction industry to create the Hodgson Hy-Spec Hybrid range. This new generation of sealants not only address the issues presented by standard hybrid sealants, they also offer dramatically improved features. Developed and manufactured within the UK, Hodgson Hy-Spec Hybrid sealants provide the possibility of greater sealant strength, with higher extension and movement accommodation. They have no surface tack, and therefore a faster cure, and have low VOC properties. Virtually odourless, they are solvent and isocyanate free, with a stable formulation and long shelf-life. Furthermore, some products in the Hodgson Hy-Spec Hybrid range have also been independently tested and found to meet the requirements of EN15651 Part 1 for ‘sealants for non-structural use in joints in buildings and pedestrian walkways’, in addition to ‘sealants for façade elements’. The products are also manufactured under ISO 9001, IS0 14001 and ISO 18001 quality management systems. When selecting a sealant for the joints in your building’s façade, it is essential to find a suitable product that not only enables both optimal appearance and performance properties, but also overcomes the limitations of traditional silicone and polyurethane sealants. A hybrid range, such as the Hodgson Hy-Spec Hybrid, delivers a strong and stable sealant ideal for fast cures and assured building performance. Hodgson Sealants offers to test customerspecific substrates for adhesion and compatibility to ensure the product offers the best performance possible. www.hodgsonsealants.com


RCI January 2018
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