Soakers are an integral part of weatherboard construction as they are an effective way of keeping water from gaining access to the ends of weatherboards when butted up on external corners.
When selecting soakers it is important to get the correct sizing and soaker material to match the cladding. Galvanised soakers should not be used on cedar weatherboards due to the interaction of natural acids in the timber and the metal. In this instance copper or stainless steel are recommended.
To ensure a correct fit the soaker selected should be appropriate to the profile of the weatherboard and its width. The soaker will need to cover the exposed wall but not the full width. In other words a 150mm board will use a 135mm deep soaker with a return of 18.5mm if it is a standard thickness board. This allows for the timber to overlap but not to cover the drain channel.