It does look as though the main cause of the rot that spread throughout our bathroom floor came from the toilet cistern, which is boxed in and seemed to be forever sweating litres upon gallons of water. After fitting the new floor, we lifted the lid to find condensation was still running and forming around the outside. Insulation is a popular solution to this, with the internet throwing up the suggest to lag around the inside with either an old gym or exercise mat or, good old expanding foam.
All along, I’ve felt as though ventilation (drilling a hole through the exterior wall and fitting a vent) would fix this. My dad’s solution was to throw a towel over the cistern and to ‘insulate’ it that way… Although the situation eased at first, it didn’t go away.
Over the last few days, we’ve made a decision to leave the lid up on the fitted surrounding unit (I used the towel for this purpose) and, low and behold; we haven’t seen a drop of water falling from the cistern since! The chipboard floor has also had a chance to dry out!!
(That jug at the bottom collects nothing.)
So, I’m now looking in to drilling a hole somewhere the rear wall that’ll allow me to fit a vent… We’re probably talking 100mm in diameter here, which could mean hiring a diamond core drill, as I don’t think I could justify buying a new one right now.
There doesn’t appear to be a lot of room but, if I can remove the front panel again, I might be able to find a way through an area just beneath the cistern and to the left. I’m not sure whether it’s best to have the vent higher or lower in this situation but I don’t recall seeing any pipes heading up this part of the wall when we had the floor out.
My dad’s adamant that we need a complete new cistern, although there is still the issue of the ill-fitting cistern lid – it looks as though they guy attempted to cut the back edge off so it would fit but actually trimmed the front… Either that or, it’s a different lid from a different toilet! That towel only seemed to absorb the water, rather than preventing anything. Fitting a vent could lead to an increase in draughts but, as this area is sealed off, I could close off any gaps between the units with strips of self-adhesive draught-proofing strips.
I apologise for the two blurry photos above. They were actually taken with my camera and not my phone. I think I was breathing a bit heavily down the cavity as I tried to hold a torch in my left hand… 😛