Failure of sealant joints usually occurs because of incorrect application, either when the wrong type of sealant is used, it’s incorrectly applied, insufficient provision is made for expansion, or due to other errors.
So how can you ensure that the job is done properly and prevent sealant failures from occurring?
The most common reason for failure of exterior sealants is the size of the joint. Joints are there to allow for expansion of other materials: if they’re in the wrong place or they’re the wrong size, then they won’t be able to absorb the amount of expansion needed. This can lead to failure of the joints but also to cracking occurring elsewhere.
It’s usually better to have multiple small joints than a small number of large ones. However, when specifying silicone sealants, architects and designers need to take account of factors such as changes in material and changes of angle on the surface. It’s also important to consider weather conditions – wind, for example, may cause panels to flex.
The Right Sealant
A good supplier such as www.ct1ltd.com will stock many different types of sealant. There are lots of things to take into account in sealant selection, and if the joint is to have a long life it’s important to get it right.
The choice of sealant needs to take account of flexibility. Some joints move more than others and the sealant used needs to be able to take account of the amount of expansion required. How the sealant recovers is important too. Although most will stretch, not all will return to their original shape afterwards, leading to premature failure.
It’s also vital to consider the environmental conditions, including how the sealant stands up to exposure to UV light. Some types will harden and dry out over time, leading to cracking or discolouring which makes them look unsightly. Depending on the conditions, you may also need chemical and abrasion resistance. Ability to resist dirt is important if you want to ensure the building continues to look good.
As well as the right sealant you also need to ensure effective preparation. The joint needs to be clean and properly primed or prepared to ensure an effective application. It’s also important to consider conditions on the day of application, ensuring that it’s dry and the temperature is right.