Termites attacking timber and plastic sheeting on tents
Emergency (timber and plastic sheet) shelters are being aggressively attacked by white ant (termite) despite the lower ends of the embedded timber frames being treated.
Any suggestions to (a) arrest current termite attack and (b) to prevent future attack requested urgently.
Solutions need to be practical and low cost and readily resourced (limited supply and logistics into north Sri Lanka) and due to the potential scale
have a look at humanitariantimber.org - the booklet for download there has a summary of key points re: termites and timber(section 9.4)..
the best document on this is building out termites - have a copy at home - best sourced through Amazon or similar second hand bookseller as it is out of print. happy to chat if better support is needed - or call Dave Hodgkin - he is great on this kind of thing..
Mixing wood ash into the soil around the pole footing is reportedly meant to discourage termites attacking the poles in Somalia. although I don’t have first hand knowledge of seeing this working myself. It a cheap (potentially free) solution though if it works, so may be worth a crack.
Other option could be to clad the pole footing with old tin cans. I’ve done this with unskilled labour and seemed to work ok. Another potentially cheap option if you can get hold of WFP oil tins for free from distribution centres, but needs a lot of labour…
OR…design some kind of detail that separates the timber pole from the soil all together.
OPTION 1- A small concrete footing around structural poles (e.g. corners only) might reduce degradation in the key structural parts of the shelter. Half a bag of cement per family, plus four buckets of aggregate and some sand ought to add some durability for limited financial outlay.
OPTION 2 – (the gold plated option!!) would be to supply a precast concrete footing with a L section metal fixing plate welded in. Then you bolt your poles to the metal upstand in such a way that the poles don’t touch the ground. This is fairly standard construction detail in lots of places globally where you don’t want timber touching the ground. This could be cheap if you manufacture on site with a casting mould and an angle grinder.
One technique I have come across in the West Indies is to paint on used engine oil. Not only is this messy, I hate to think what the environmental consequences are. One way around this is to bore a hole in the timber at an angle and putting the oil in it so that it can soak through the wood. Not very effective on dense hardwood, but generally this is less susceptible to attack.
The other important consideration is avoiding embedding timber at all, but this is probably not appropriate for emergency shelter.
As usual, the first response would be to ask locally how they deal with the problem. If that is not effective you may wish to consider the following, however our experience is not extensive, being limited to eastern and western Africa.
Look at insect control in the index, or pages 258, 278, 284. A termite shield is usual, however this requires a continuous wall, or posts bolted to steel in concrete pads rather than in the ground (converting any block making capacity locally into a temporary pad foundation factory might work). Ensure that the angle of the shield overhang is 45 degrees and there is no break, especially at door sills. Also, termites tend not to like passing over plastic sheeting, especially if stretched as walling, as the tunnels they build on the surface to avoid the sunlight do not adhere easily to it.
A layer of ash is used in some cultures in mud walls, however I have no knowledge of its effectiveness, and it would need to be implemented carefully.
One other method for prevention is digging up and setting fires in the termite mounds in the area, ensuring that the queen is killed. Termite mounds have underground pathways that can run for a very long distance. This process needs to be continually monitored. Beware setting a bounty on termite queens, as they might come from any mound. Community participation can be effective, especially if picks and shovels are supplied (I also managed lunch from a feeding centre). Termite mound earth often makes excellent mud bricks.
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