TOILET CISTERN All aspects of plumbing questions and answers, help, tips and information

[L&A]

Hi. could expanding foam be used to line my toilet cistern in an attempt to stop condensation? I'm not sure if it is waterproof. I realize that I will need to restrict its expansion, but is it waterproof?

[plumbbob]

Probably not. I would think it would interfere with the workings of the cistern fittings, and more importantly, would reduce the cistern capacity of water, which in turn would prevent the toilet from flushing properly.