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Reader Dave – Termite Control?

from Dave

You have to be careful that the wood used for measurement and forms is not left in the floor when cement is poured. This leaves a track for termites.

Also, many tile installers do not fully fill the area under the tiles, allowing a termite path.

Anyone have tips for termite prevention ?

Poison is useless. It is not used to actually kill termites (only making a barrier). But Thais consider this the primary action.

Some houses have a sand substrate. I could never get a good reason for this, but it can be used to prevent termites.

I find that commonly sand about 1.6-2.4 mm (95%) can prevent termites in the US. Any specs for Thailand ?

Editor: Yes, termites are a huge problem here. My friend when doing a remodel project on an older house actually had the floor broken up and removed, then went beneath the floor an mixed termite poison in with the soil. After that the floor was replaced! This was pretty effective.

The normal treatment of pest control companies of drilling a small bore hole and force spraying poison to the sub strata doesn’t seem to be that effective. The best time to try to treat is before construction starts.

I think normally the reason for the sand substrate is to prepare the house subfoundation with material that will not settle. I never thought about it as a method for controlling termites but it probably isn’t a bad idea.


  1. Hi Dave I have an ongoing termite problem in our village house. They came in through a tiny crack where the floor meets the wall If you google for termites you will find a lot of info from australia where its a savage problem

    The bottom line is that you cannot completely eradicate termites. You simply make it unpleasant for them. Local lore says spray with old diesel engine oil periodically. The worst thing is getting them in the roof void when using wooden rafter construction – very nasty In short dont use wood at ground level, fill in any cracks with silicone mastic. Inspect once a month, look for tell tale mud tracks, particularly around wooden door frames – jambs they can creep up inside unnoticed. The only way is to get a young thai lady to bend down and put her ear to the post. She can hear the critters munching away Another problem is any kind of wardrobe that is rarely moved. You would be amazed what will go on behind one of these. I found a huge tokai nest (those big house lizards) I dont see the logic in sand? they will just tunnel through it if they smell food. I think the main nests are up to a metre below ground which is why they are so difficult to eradicate. They dont respond to the conventional japanese ant poison I once had an infestation in a woodblock floor of an appartment that was on the fifth floor of a condo!! I moved

    rgds Robin

  2. The key to the sand is that it must be too big for them to move and too small to hold position (not allowing a hole as they build). There is an optimal size – from 1.6-2.4 mm seems to good basec on my “Internet Research”, but it depends on the type of termite. I don’t know what termites are found in Thailand. Perhaps there is a University in Thailand that has done this research ? This is a science.

    An alternative is to use a stainless steel mesh of a specific size, but this must of course be done during construction – sand can be done afterwards. I didn’t find the mesh in Thailand – it may be expensive in relation to Thai house prices.

    Great care must also be taken during construction to avoid cracks. We are lucky in Thailand because their are not high temperature swings which cause expansion/contraction cycles to worsen cracks.

    Also avoid leaving bait around – remove all wood and paper rubbish (don’t bury it next to the house, which is popular with lazy contractors). And don’t leave things next to the house (and don’t plant shrubs next to it.

    Avoid stupidity as well – I had an apartment where the door frames when all the way into the ground…

    Most Thai house have an additional helpful feature which helps – the concrete walkway. Termites don’t like to walk horizontally, so they avoid the walk over the walkway. Just avoid the crack between the walkway and house.

    Additional care should be taken where PVC pipe comes into the house – avoid it if at all possible. (Go into the ground outside the house is better, but watch out for the crack between the walkway and the house…). It’s hard to get rid of the 4″ sewer pipe for the toilet however – so special attention must be paid to this.

    As for poison, basically it is not used to kill them – there are too many (unless you use one of the baits that they bring back, which is only temporary). So the house must be made “termite proof” – if there is no way in, they can’t come. And you make it “undesirable” as well.

    The poison provides a temporary to stop them from passing a certain line. Obviously the line has to be complete or they go around it (so all the around the house, and don’t trap them inside the under house area). Oil is just another type of poison.

    I prefer not to use poison if I can help it. As for Doo-Gae, I like them. As they say, if the lizards won’t live in your house, then there must be a problem with it. So I have lots of lizards. As with the expansion of masses of people (eating them…), I had to travel far to get a seeder-bunch. But now I have a healthly population to add ambiance to nice evenings under the porch with a ice cool beer in hand !

  3. Hi Dave

    I did a web search when I found our problem

    Dr Don’s Termite page


    University of Kentucky


    There’s a lot about

    I couldnt find Fipronil in Thailand so I ve resorted to used engine oil and silicone mastic

    Much of what you mention above is quite right. Never seen SS mesh, it would be very expensive.

    How about a layer of PVC sheeting which acts as a dampcourse and termite proofer? thats cheap enough a 600 baht roll would cover 1.5 m x 30 meter

    With the sand I guess you would have to seive it, but really if you have a 100mm reinforeced concrete floor with tiles and a tiled skirting strip, you should get a problem



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