Termite Proofing in Naval Housing Scheme Karsaz: Every Extension Broke the Barrier at the Joint

Termite proofing in Naval Housing Scheme homes is rarely a fresh whole-house job. Most NHS Karsaz and Zamzama houses have been extended, re-floored or re-plumbed at least once, and every one of those alterations cut a seam through whatever soil barrier existed before. Our termite proofing work in this scheme is therefore mostly seam work: finding the joints where old slab meets new, and closing them.

A house that has been altered is a barrier with joints in it

Picture the history of a typical Naval Housing Scheme house. Built decades ago to a standard plan. A room added at the back in one decade, a kitchen widened in another, bathrooms re-plumbed when fittings wore out, floors lifted and re-laid in tile or marble somewhere along the way. Each of those projects poured new concrete against old. Concrete cast at different times never fuses into one piece; it meets at a cold joint, a hairline seam running from the soil right up into the floor. Even where the original construction had anti-termite treatment under it, the extension slab usually went down on untreated fill, and the joint between the two is a ready-made channel wide enough for termites, which need less than a millimetre.

In the altered houses we survey in this belt, activity maps onto the alteration history with striking regularity: the back-room addition, the widened kitchen, the re-laid bathroom floor. Homeowners are often puzzled that the oldest part of the house is clean while the newest part has damage. Once you know where the joints are, it is not puzzling at all.

What comes up through the seam

Coptotermes heimi is the main structural threat here, a deep soil-nesting species that follows moisture and finds cold joints, pipe sleeves and expansion gaps with remarkable efficiency. Heterotermes indicola turns up as the thin mud lines on boundary walls and inside store rooms. Both are subterranean: the colony stays in the ground, and the house is a feeding site reached through whatever gap the structure offers. That is why the joint matters more than the wall above it. Kill the traffic in the seam and the wood damage stops; spray the skirting and ignore the seam, and the colony simply routes around your effort.

How we treat a jointed house

The survey comes first, and in NHS houses it is partly an interview: when was the extension built, where did the plumbing move, which floors were re-laid. We map the joints before we drill a single hole. Treatment then concentrates on the seams: drilling at close centres along both sides of each construction joint, at the wall-floor junction of the altered rooms, and around every pipe penetration, then injecting Imidacloprid ^[1] 17.8% SC (Premise 200 SC) at label dilution so the soil each seam feeds from becomes a treated zone. Imidacloprid is non-repellent; termites moving through the joint pick up the active without detecting it and pass it through the colony by contact and grooming. The perimeter still gets attention, but the metreage concentrates where the house’s history says the risk is, which is also why two NHS houses of identical size can be quoted differently.

The honest limit: some joints sit under finished floors

Now the part that works against us commercially. Some construction joints run under fitted wardrobes, kitchen cabinetry or expensive marble that the owner does not want lifted. We can often reach the seam by drilling at an angle from the nearest accessible line, but not always, and where we cannot reach it we say so on the survey sheet rather than drilling a cosmetic line nearby and calling the house covered. You will get a quote for an honest partial with the unreachable run marked, and the warranty wording will reflect it. If a competitor promises full coverage without lifting anything, ask them to draw the joint plan they treated; the difference between our pre- and post-construction methods exists precisely because finished structures hide their own geometry.

Moisture: the second half of the alteration story

Alterations do not only cut joints; they move water. A re-plumbed bathroom carries new pipe runs through old fill, and a slow weep at a buried elbow can keep the soil under a floor damp for years without ever showing on a wall. Damp fill beside a cold joint is the complete termite invitation: moisture, access and wood in one place. During the survey we check floor-level dampness along the altered sections, and where we find an active leak we tell you to get the plumber in first, because injecting termiticide beside a leaking pipe treats a symptom while the leak keeps recruiting the next colony. Sequencing the plumber before our crew occasionally delays our invoice by a week. It also means the treatment we eventually do stays done, which is the version of this work we are prepared to warrant.

Planning an extension now? Treat before the slab goes down

If you are about to add a room or rebuild a wing, you are in the one moment when the seam problem can be prevented instead of managed. Treating the excavation and fill under the new slab, plus the contact line where it will meet the old structure, costs a fraction of remedial work and closes the joint before it exists. That work is covered on our pre-construction termite treatment page and carries the 10-year warranty; remedial treatment on a finished house carries 1 year, extendable to 5 on an annual maintenance contract. Tell your contractor before the plinth fill goes in; a day’s coordination buys a decade of coverage on the new wing.

Where we work around the scheme

Our crews cover Naval Housing Scheme Karsaz, NHS Zamzama, the residential lanes off Karsaz Road, and the streets on the DHA Phase 5 boundary side; residents often give PNS Shifa as the nearest landmark when booking, which works fine for routing. The office sits in DHA Phase 4, a short run from either pocket of the scheme, so surveys are usually scheduled within a couple of days. Postings mean occupants change here more than in most of Karachi; if you have just moved in, a survey is worth more than in a house whose history you know, because you inherited the alteration seams without the story that explains them. Ask the outgoing family what was extended and when; it shortens our joint-mapping considerably.

What it costs

Seam-focused work is priced by what the survey finds: the linear metres of joint and junction to be drilled, access, and floor build-up. Every NHS job is quoted after inspection, with the joint plan attached so you can see what you are paying for. Our city-wide rate structure and the factors that move it are published on the termite treatment cost page; a Naval Housing quote should sit inside those bands, and you are welcome to check ours against them. For a worked example of how we document a comparable job end to end, see our DHA treatment case study.

Naval Housing Scheme termite questions

The old part of my house is fine but the extension has termites. Why?

Because the extension slab almost certainly went down on untreated fill, and the cold joint where it meets the original structure is an entry channel. The original build may have had soil treatment under it; the addition rarely does. Treating the joint line and the soil under the altered section addresses the actual route.

Do you have to lift my marble floor to treat the joints?

Usually not. Most joints can be reached by drilling 12 mm holes along the seam line and injecting under the floor; the holes are sealed and pointed afterwards. Where a joint genuinely cannot be reached without lifting finished work, we mark it on the survey and quote the honest partial instead of implying full coverage.

How long does the treatment take in an occupied house?

A typical NHS house is one working day: joint mapping confirmed in the morning, drilling and injection through the day, holes sealed before the crew leaves. You do not need to move out; we work room by room, and treated rooms are usable again the same day once injection points are sealed and the area is cleaned.

We are tenants on posting. Is it worth treating a house we may leave?

The warranty attaches to the treated house, not to the occupant, so work done during your stay protects the next family too. Practically, most occupants treat when there is visible activity, and coordinate with the scheme office or owner on cost. We document everything so the paperwork survives the handover.

Is a yearly spray enough to keep deemak out?

A surface spray does not reach a subterranean colony and does not close a construction joint. What works is treated soil at the entry geometry, then annual inspection to catch new activity early. If someone is selling you an annual “deemak spray” with no drilling and no joint plan, you are buying reassurance, not a barrier.

Book a survey in NHS Karsaz or Zamzama

If you have mud tubes on a wall, soft wood in an extension, or you have just moved into a house whose history you do not know, call +92-311-1101810 or email contact@nestfumigationservices.com. We will map the joints, show you the entry geometry, and quote the treatment your house actually needs, in writing.