i believe for long term solution to prevent termites is to seek help from pest control company to do perimeter drilling plus chemical injection (agenda EC) or you may try DIY by get the Stedfast termite solution from local hardware shop

TERMITE SOIL BARRIER TREATMENT

AGENDA 2.5 EC

Agenda’s (formerly Termidor) unique mode of action combines structural protection and colony management. It uses a new molecule called Fipronil, which is extremely active even at low doses. Agenda is made from a revolutionary non-repellent or undetectable chemical technology treatment. This means termites cannot see, smell, taste or avoid Agenda. Instead they contact, ingest, and share it with their nestmates. This amazing feature of Agenda makes it the Number 1 termite defense product in the world today.

Agenda is a termiticide that has been tested in Asia and around the world. Due to the tropical conditions and high intensity of termites often encountered in Asia, these trials represent the toughest test for any termiticide. No other termiticide in recent history has demonstrated such complete effectiveness at such a range of sites as Bayer's AGENDA.

Stedfast® Liquid. Repellent with quick knock-down. Optimal for long-term protection in combination with Ceptiva®. Termites Alpha-
Cypermethrin
http://www.agro.basf.com/agr/AP-Internet/asean/en_GB/

agenda ec aka termidor

http://www.termidorhome.com/