Mould and Condensation

I have recently built a holiday house on the South Coast of NSW.
Towards the end of last summer I had finished the downstairs storage, laundry, bathroom and had noticed after installing the fridge we had a large amount of furry mould start growing in certain areas. After cleaning and relocating the fridge to upstairs the problem seemed to be solved.
I have had the room waterproofed internally and externally but it is on the south side of the house with little air movement from the outside. I now have the problem of condensation on the tiles to about 300mm from the floor. The toilet also has condensation. This condensation is now collecting on the tiled floor and a black spotted mould growing.
My thoughts are that the humidity from the outside is entering the window and condensating on the cold tiles and toilet. I do not think it is moisture tracking through the external walls. Should I install an in line duct fan on timer to get the air moving or be sucking fresh air from the outside. Any ideas greatly appreciated.
Regards,

Brett :D

Sounds like its drawing moisture from the ground around it, is the bottom floor dug in to the earth at all??

The slab was laid on black plastic. All the external walls were painted with a bitumen paint and internall walls waterproofed. Only half of one wall has gravell against it and this has aggy line to take away the water.

BB:D

The problem is that you have "waterproofed" the area. I suggest you do some research into "vapour barriers" & "vapour blocks". Increased airflow should solve the problem.