How to stop condensation under toilet lid?

gnomy1

Hi all,

Noticed there was some moisture near the top of my toilet lid. So took  off the lid to take a look (see pic). Both toilets pretty much look the same, where it looks like condensation/splash back is making the cut out section damp.

Seems like a terribly poor design to me! 

I'm wanting to prevent any damage, and coming into the hotter months, it's likely condensation will increase.

Was hoping for some suggestions to protect the back of the wall? Maybe silicone, spread thinly to create a waterproof barrier?

Any help would be greatly appreciated!

Kind regards,

Emma

MitchellMc

Welcome to the Bunnings Workshop community @gnomy1. It's sensational to have you join us, and many thanks for your question about moisture in cisterns.
 

What you’re seeing is very common and is almost always condensation rather than a leak. Cold water sitting in the cistern cools the porcelain, then when warm, humid air hits it, moisture forms and runs down into that recess and onto the wall. In hotter months with higher humidity, this can definitely get worse, especially if the bathroom doesn’t ventilate particularly well. It’s also worth keeping this in perspective. Your toilet has likely been in place for quite some time, and from what you’ve described and shown, there doesn’t appear to be any visible damage to the wall or surrounding area. That suggests the moisture has been fairly minor and intermittent rather than an ongoing issue causing deterioration. Taking a few preventative steps now is sensible, but it’s reassuring to know that the existing setup hasn’t shown signs of harm, so this is more about future-proofing than fixing a serious problem.

Your thinking about protection is on the right track. Running a neat bead of wet-area silicone along the cut-out edge and lightly spreading it to form a thin waterproof barrier is a perfectly reasonable approach. You’re not trying to glue the cistern to the wall, just create a moisture-resistant skin so any condensation can’t soak into plaster or paint. Make sure the area is completely dry before applying it.

Improving ventilation will also make a big difference. If you have an exhaust fan, make sure it’s working well and being used during and after showers. Even cracking a window can help reduce humidity and condensation overall.

Please let me know if you have any questions.

Mitchell