The tents in the camp we are managing are leaking. It is cold and it is raining. The tents are single skin canvas family tents and we have tried waterproofing them using a layer of plastic sheeting, but they are still very wet inside. What can we do?
This is a question that I've been asked in the field so I wanted to share it with everyone on KnowledgePoint
Thank you for your question. Tents should be kept dry inside because damp can encourage mould growth and respiratory infections.
There are two possibilities. The first is that the tents are indeed leaking when it rains, and the second is that condensation from breathing, sweating and cooking, is building up in the tents causing the canvas to remain damp. If the tents are leaking then it will be noticeably worse when it rains, with dripping from specific places, and damp patches are likely to be localized around the seams. However, the area of roof directly under the plastic sheet should stay reasonably dry. If condensation is the issue then the damp will be fairly evenly spread across the roof.
If the tents are leaking it is possible to purchase waterproofing spray, but the tents will need to dry out before using it. You will need access to alternative accommodation for the families close by so you can rotate them into it while you treat a small number of tents at a time.
It is more likely that condensation is the problem, and plastic sheet touching the canvas will trap the moisture in the tent. Fixing it away from the canvas may help. This can be done by attaching guy ropes to the four corners of the sheet and at one meter centres, then pegging out the ropes so the plastic sheet is at a shallower angle than the roof of the tent. The plastic sheet may still provide some benefit by trapping warm air just above the canvas, which is the principle of a double fly tent. In general single fly tents should not be used for family shelter.
For details on how to attach ropes to plastic sheet please see: Plastic Sheeting: A guide to the use of plastic sheeting in humanitarian relief, Chapter A.5, Fixing Plastic Sheeting p26. http://policy-practice.oxfam.org.uk/p...
To reduce the condensation the tent must be ventilated as much as possible. This is not easy in cold weather because it means letting in cold air, but if the family can leave the doors open several times a day this should help. Reducing the number of people staying in each tent will also contribute, if you have enough land, additional tents and families who are willing to split their members between tents.
A more radical, but common, solution is to locate the tents in a large indoor space such as a hangar or hall, where the air immediately outside the tents will be dryer and warmer. An added benefit to this arrangement is the large covered space outside the tents that families can use without getting cold.
Tents are the best answer in many cases. However with so many climatic problems, there needs to be something else. These needs to be something that is fast and resistant to the weather over the long term. Tent-houses are the answer. Using Air-form construction. They are almost as fast to construct as a tent, are almost as strong as a house and more waterproof than any other form of normal house. Constructed with rubble. They are the ideal new method for re-homing the islands of Caribbean, helping refugees and particularly good for longer term camps. They can be constructed any size and one village of 9 structures with WC and kitchen. We have a top UK academic, experts and property developer endorsing this project. We have a very wealthy investor who wants to partner with an NGO or NGOs on this and give people solid homes. With today's weather it is an absurdity to expect tents alone to be up for the job of rapid shelter. It is incorrect to believe anything less than rapid build homes are required with today's climate. We have a prototype constructed in Surrey. Anyone interested in partnering with us please contact me.
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