Buying a House in Bangkok? Get the Termite Inspection Before You Sign

Buying a house in Bangkok involves a surprising amount of trust. You'll have a lawyer check the chanote, an agent walk you through the rooms, and a bank value the land. What almost nobody arranges — especially first-time buyers from countries where it's standard — is a termite inspection before buying the house.

That's a strange gap, because the ground every Bangkok house sits on is home to Coptotermes gestroi, one of the most destructive termite species anywhere, and the thing you're about to pay for is the part of the property it eats. The land keeps its value regardless. The built-ins, frames, parquet and roof timbers do not.

This guide covers what a pre-purchase termite inspection actually involves, when in the Thai buying process to book it so it can still change the deal, what sellers (not always deliberately) hide, and what to do with the report once you have it.

Why Thai property deals leave you exposed

In many countries, a house sale comes with a statutory cooling-off period or an inspection contingency built into the standard contract. Thai residential transactions typically don't work that way. The usual sequence is:

1. Reservation. You pay a small deposit to take the property off the market.
2. Sale and purchase agreement. A contract setting out the price, the transfer date, and the conditions. A larger deposit usually changes hands here, and it's normally forfeited if the buyer walks away without a contractual reason.
3. Transfer at the Land Office. You and the seller (or your representatives) meet at the district Land Department office, the balance is paid, taxes and fees are settled, and the title changes hands. Once the clerk stamps it, the house is yours, with whatever is inside the walls.

Between steps two and three there is often only a few weeks, sometimes days. After step three, there is no going back. So a termite inspection is only useful if it happens before the sale and purchase agreement is signed, or if that agreement contains a clause making the sale conditional on a satisfactory inspection. Ask your lawyer to write that clause in; it's routine and sellers with nothing to hide rarely object.

For expat buyers, the timing problem is sharper. Many arrive for a few days of viewings, put down a reservation on the Friday, and fly home. The inspection has to be arranged in that window — which, with an operator who works daily and covers all BTS and MRT zones, is entirely possible.

What a pre-purchase termite inspection actually covers

A proper inspection is not a man looking at the skirting boards. A licensed termite inspection should take an hour or more on a typical house and cover:

The exterior and perimeter

• Foundation line all the way around, looking for mud tubes where soil meets concrete
• Soil and garden bed levels relative to the internal floor — soil piled above the slab is a bridge over any barrier
• Air-con condensate drip points, outdoor taps, downpipe discharge: the damp spots where activity starts
• Carport, terrace and extension joints against the main house
• Any under-slab pipe injection points, and whether they're capped and real

The interior

• Every door and window frame, tapped and probed at the base
• Skirting and architraves for blistered paint, pinholes, mud packing
• Inside and behind built-in wardrobes and kitchen cabinets — the back panels and the floor beneath the bottom drawer
• Parquet and engineered timber floors for soft spots, lifting, hollow sound
• Bathroom and kitchen walls where pipes enter, the classic riser pathway
• Roof space and ceiling access, where available, for timber battens and purlins

The readings

• Moisture meter readings on timber and walls. Elevated moisture in a frame with no plumbing nearby is a strong signal even when nothing is visible.
• Activity detection — visual confirmation of live termites, frass, or fresh mud where accessible.

The output

• Photographs of every finding with location
• A written report: what was found, where, what it means, and a fixed-price proposal for treatment if any is needed

PestsRova's licensed termite inspection is ฿990 (free with any year package) and includes exactly that: moisture and activity readings, photographed evidence, and a written fixed-price proposal. The report is yours to use however you like — with your lawyer, with the seller, or with another company for a second quote.

Which houses deserve the most scrutiny

Every Bangkok house should be inspected, but some types come with a heavier prior:

| Property type | Termite exposure | Why | Specific things to check | |---|---|---|---| | Older detached house (pre-2000s) | High | Decades of soil contact, often no original treatment, more timber | Roof timbers, original frames, any extension joints | | Townhouse in a row | High | Shared footings and party walls; your risk is the row's risk | Party walls, rear kitchen extension, neighbour's condition | | Shophouse | High | Ground-floor commercial use, storage against walls, old timber stairs | Stair stringers, mezzanine floors, rear service area | | Newer moo baan house (under 10 years) | Moderate | Usually pre-treated, but barriers age and landscaping bridges them | Treatment certificate, raised garden beds, carport slab | | Renovated "flip" | Moderate to high | Fresh finishes hide old damage; the colony didn't leave | New laminate over parquet, freshly painted frames, new built-ins | | Khlong-side or flood-zone house | High | High water table degrades soil barriers faster | Lower wall moisture, ground-floor timber, any flood staining | | Ground-floor condo or low-rise unit | Moderate | Soil contact or podium gardens | Garden-side frames, riser walls — see our condo termite guide |

What sellers hide (and what they genuinely don't know)

Most sellers are not villains. Many honestly have no idea, because termites work inside timber and leave the surface intact. But an inspector learns to read the staging:

• Fresh paint on door frames only. Frames get painted because they look tired — or because the paint was blistering from termite moisture underneath.
• New laminate flooring in one room. Laminate is the fastest way to cover a parquet floor that went soft.
• Furniture pushed hard against walls. A wardrobe that hasn't moved in years can have a mud tube running up behind it.
• A new built-in kitchen in an old house. Perfectly normal renovation, and also the most common thing replaced after termite damage, with the colony still under the slab.
• A strong smell of air freshener or a house that's just been deep-cleaned. Not evidence of anything, but it's the moment to pull out the bottom drawers yourself.
• Absent paperwork. "The previous owner did termite treatment" without a certificate, a date or a company name is a sentence, not a treatment.

Ask the seller directly, in writing, whether the house has ever been treated for termites, by whom, and when. A truthful answer is useful either way. An evasive one is also useful.

The pre-purchase termite checklist

Work through this before the sale and purchase agreement:

• [ ] Ask the seller, in writing: any termite history, treatments, certificates, warranties?
• [ ] Ask whether the house has an under-slab pipe system, and where the injection points are
• [ ] Walk the perimeter yourself: soil level vs floor level, mud tubes, damp spots beside the air-con units
• [ ] Open every built-in and look at the back panel and floor under the bottom drawer
• [ ] Tap every door frame at the base; note anything papery
• [ ] Look at the neighbours: a townhouse row with one unit visibly unmaintained raises your risk
• [ ] Book a licensed termite inspection with moisture readings and a photo report
• [ ] Have your lawyer add an inspection condition to the sale and purchase agreement
• [ ] Get any treatment proposal in writing, fixed-price, before negotiating
• [ ] Decide: proceed, renegotiate, require seller treatment with a certificate, or walk

What to do with the report

The inspection produces one of three outcomes.

No activity, no damage, low moisture. Proceed, keep the report with the house documents as a baseline, and plan a post-purchase barrier or annual monitoring. A clean report is also a useful thing to hand to your own buyer in ten years.

Activity or damage found. Now you're negotiating from evidence rather than nerves. Options, roughly in order of how often they make sense:

1. Price reduction covering treatment and repair. A written fixed-price treatment proposal makes this a number rather than an argument. Full termite programs at PestsRova typically run ฿5,000–15,000 depending on structure and method; repair of frames, floors or built-ins is separate and depends entirely on the extent.
2. Seller treats before transfer, with a certificate from a licensed operator naming the product and scope, and ideally a warranty that passes to you. Insist on seeing the treatment report, not just an invoice.
3. Walk away. Rare, but sensible when damage is structural — roof timbers, floor joists in an older house — or when the row or the neighbourhood makes long-term control unrealistic.

Damage found, no current activity. The most ambiguous result. Old damage with a dead or relocated colony is common and may just need repair. But "no activity today" in the dry season doesn't mean much; the colony forages hardest in the monsoon. Treat the house as if it's exposed, and budget for a barrier.

Which treatment, if one is needed

If the inspection finds a problem, the method depends on the house. A detached house with soil on all sides and no active infestation is a textbook case for a perimeter soil barrier using a product like BASF Termidor HE, applied once and recharged every few years. A townhouse with an active colony and neighbours you can't treat leans toward the Exterra baiting system, which kills the colony rather than deflecting it. Our soil barrier vs baiting comparison covers the trade-offs, and the baiting explainer goes into how elimination actually works.

Timing matters too. A barrier protects from the afternoon it's applied, which suits a deal closing in three weeks. Baiting takes months to eliminate a colony, so if the seller is treating before transfer, a barrier plus localised treatment is usually what fits the calendar, with baiting added afterwards if activity continues.

Either way: quoted in writing, after inspection, never before. Any company that names a treatment price over the phone for a house it hasn't seen is guessing, and the guess is rarely in your favour. Current inspection and program figures are on our pricing page, and the products we use are listed on the products page.

After you buy

The inspection report is the first page of the house's termite file. Add to it:

• The treatment certificate and warranty, if treatment was done
• The under-slab pipe map, if there is one
• An annual inspection, which is included free on any PestsRova year package, or ฿990 on its own

And watch the first rainy season. Wings on the windowsill after the first big rains are normal in Bangkok; wings emerging from inside a wall are not. Our flying termites guide covers how to tell, and the warning signs post lists what to check every six months.

The short version

A termite inspection before buying a house in Bangkok costs ฿990, takes about an hour, and has to happen before you sign the sale and purchase agreement — or be written into it as a condition — because after the Land Office transfer, the house and everything eating it are yours. The report turns a gut feeling into a photographed, moisture-metered document you can negotiate with.

If you've got a reservation down and a transfer date looming, book through our termite control page or message PestsRova on LINE (@pestsrova) or WhatsApp. We're licensed, insured, open daily 8:00–20:00, and cover every Bangkok BTS and MRT zone from Ari to Bang Na — with English-speaking lead technicians who'll walk you through the findings, and a photo report in your inbox before you've finished the coffee.