Sweating Containers

Our fears of sweating containers

  July, 2015

I am frequently asked about containers sweating. When I started this project, I heard or read tales of how containers sweated, and I would have to put in drain holes every few feet to let the water out. The containers would rust, and it would be terrible. I made pictures in my head of rivers of condensation running down the walls. For some reason, I started building them anyway.

The theory goes something like: A thick wall of steel that has two different temperature on either side, will create condensation. Much like it does on your house or car windows in certain conditions.

Containers are fitted with tiny vents in each corner.

I was concerned water would be running down the walls and dripping off the ceiling.

My precautions: Blind optimism. I put a layer of silver insulating bubble foil over the ceiling panels so the water would not drip into the electrics. I used a layer of the same foil on the walls in most places to begin with. But not all areas.

My experience: The rivers never appeared and no drips from the ceiling have been felt.

Even with some areas of the container being exposed steel, we never saw moisture that caught our attention. We have dry carpets and no mould. Living in the container house is quite open plan. We experience more of the weather than in our previous suburban dwelling. We keep the window open, most of the time, and the house is generally well ventilated. With no condensation in summer we noticed, I thought it would appear when we had the fire on in winter. Still no dampness was experienced.

When the second container came on line, and the shower was operational I thought that we would see it then. I even fitted a metal ceiling over the bathroom so it would drip without damaging the ceiling. I installed a 240v extraction fan by the shower. Apart from the day I was testing the fan, it has never been turned on. The roof above the shower has never dripped.

We live with the kitchen cargo doors open, with flyscreens all year. We close them at night. In summer we have the bedroom cargo doors open for cooling on warm summer days and evenings.

I have never gotten around to fitting extra vents, whirly birds and forced heating or ventilation.

It has been three years of living in containers, drought, rainstorms and everything in between.

My conclusion: ItŐs not as bad as people think. All the same arguments apply to your car. Yes, it sometimes mists up inside, but with a heater or some ventilation it clears quickly. You donŐt need your snorkel and flippers. My old house had a wall of glass, but we never did anything other than draw curtains over them in summer and winter.

Disclaimer: I may be lucky, live in a bubble or be missing something. If you have real experience of a problem please share your experience and the circumstances, and I will post it here for people to consider.

shipping container house interior