The surfaces that require sealing. The choice of a sealant depends a great deal on the two materials that must be insulated/sealed. There are specific products that guarantee optimum qualities of the product on different materials such as concrete, glass, wood, marble, and aluminium, etc. Choosing the right sealant guarantees that the product will adhere to and be compatible with the medium upon which it is applied.
Environmental conditions. To choose the product type it is important to consider the climate and the temperature to which the joint is to be exposed and whether it is to be applied indoors or outside.
The conditions in which the joint is to work and whether the sealed joint must withstand a lot of contraction or expansion movements.