Termites rarely announce themselves until the damage is done: a kitchen door that crumbles from the inside, a hollow door frame, a thin mud trail on a wall. They live in the soil and come up into the building from below. That is why treating the ground before the foundations is a step no careful contractor skips. This article explains why we treat first, when and where the soil is sprayed, and what you should check as an owner.
Why termites matter in a concrete villa
A fair question: if the villa is concrete and block, what is there to eat? Subterranean termites do not attack concrete; they use it as a highway. They are after cellulose, meaning wood and paper, and they get to it through:
- hairline cracks in concrete and screeds;
- construction joints and slab edges;
- gaps around drainage and water pipes passing through the ground slab;
- mud tubes they build up walls and columns to travel protected from light and dry air.
Once inside, a home offers plenty: internal doors and frames, cabinets, timber floors, the paper facing on gypsum board, stored cardboard, books and documents. Damage is usually found late because termites eat from the inside and leave the surface looking intact.
Why treatment comes before the foundations
The idea is to create a chemical barrier in the soil between termite colonies and the building. That barrier is easiest and most complete before construction:
- Full access to the ground. The excavation is open, so the product reaches every point under footings, ground beams and the ground slab.
- Even coverage. The whole area can be sprayed at a steady rate, rather than injected at scattered points later.
- No breaking out. Post-construction treatment can mean drilling through tiles and slabs.
- Protection from day one. The building starts life protected instead of waiting for a problem.
That is why it sits at the start of the below-ground sequence we follow: approved termite treatment, then a polyethylene sheet against moisture, then blinding concrete. You can see where it fits in the whole project in villa construction stages in Riyadh.
When exactly is the soil treated?
Timing matters: spray at the wrong moment and the treatment gets dug out or buried under untreated soil.
| Stage | What happens | Note |
|---|---|---|
| After excavation | Formation levelled and debris removed | Don't spray soil that will be dug again |
| Before the polyethylene | Base and sides of the excavation sprayed | The main treatment under footings |
| Before the ground slab | Compacted backfill treated | Under the whole ground floor |
| Around the building | External perimeter treated | Especially at walls and entrances |
| After services | Pipe penetrations treated | The weakest points in the barrier |
The key point is that treatment is not a single spray on day one. Any soil added or disturbed over the treated area, such as backfill, needs treating too, or it becomes a bridge over the barrier.
What products are used?
Soil-applied termiticides approved by the relevant Saudi authorities are used. We don't name brands here, because the choice depends on what is approved and available at the time. What matters to you:
- the product is approved and intended for pre-construction soil treatment, not a general household insecticide;
- it is diluted exactly as the manufacturer specifies on the label;
- it is applied at the required rate per square metre so the top layer of soil is properly soaked;
- the work is done by, or under, a licensed pest control company, with a report or certificate for your records.
Mistakes that weaken the barrier
- Timber left in the ground. Offcuts of formwork and broken boards buried in backfill are a ready meal right next to the building. Clear out all wood, paper and cement bags.
- Spraying the wrong soil condition. Very hard, crusted soil lets the liquid run off; waterlogged soil cannot absorb it. The pest control company should judge the condition.
- Disturbing treated soil. Machinery tracking across it, or extra trenches for pipes, breaks the barrier. Re-treat any disturbed area.
- Leaving treated soil exposed. Sun, wind and dust reduce effectiveness, so lay the polyethylene and pour blinding soon after. See moisture barrier and blinding concrete.
- Forgetting the backfill. The most common mistake: treating the excavation base, then pouring the ground slab on untreated fill.
What the owner should follow up
- Ask for the product name and dilution, and confirm it is approved for soil treatment.
- Ask for photos or a short video during spraying, and the treatment report.
- Confirm spraying happened just before the polyethylene, after the excavation was cleaned.
- Confirm the backfill was treated before the ground slab.
- After moving in, watch for mud tubes on walls or hollow-sounding timber, and arrange periodic inspections if your area is known for termites.
Does pre-treatment replace maintenance?
It gives strong protection in the early years, but the product in the soil is affected over time by irrigation, moisture and later digging around the building. Planters against walls and new irrigation lines are common weak points. If you are refurbishing an older villa where termites have already appeared, injection treatment becomes part of Renovation & Rehabilitation. If you spot signs, don't reach for a household spray, which may kill visible workers and push the colony to find another route; call a licensed company to find the source.
How Marafi handles it
We treat termite spraying as the start of protecting the building, not a box to tick. After excavation we clean the formation, spray the soil with approved materials, then lay the polyethylene sheet carefully to prevent moisture and pour the blinding concrete, protecting the foundations and the life of the building. The backfill is treated again before the ground slab, and owners receive photos at each step. This is part of our Foundations & Footings service and every Villa Construction project we build in Riyadh. The full sequence is on How we build.
Summary
- Termites come from the soil; concrete is a route, not a barrier.
- Treating before foundations is more complete and less disruptive than treating later.
- Sequence: excavate and clean, spray, polyethylene, blinding, then treat backfill before the slab.
- Use approved products at the right dilution and keep the treatment report.
- Keep timber out of the backfill and re-treat any disturbed soil.
About to start foundations in Riyadh? Contact us to arrange a site visit and an itemised proposal.
Frequently asked questions
When is termite treatment done during construction?
After excavation and levelling of the formation, before the polyethylene sheet and blinding concrete. The backfill under the ground-floor slab and around the foundations is treated again as specified.
Termites don't eat concrete, so why treat at all?
They use concrete as a route, travelling through hairline cracks, joints and pipe penetrations to reach doors, cabinets, gypsum ceilings and anything else containing wood or paper.
Who should carry out the treatment?
Ideally a licensed pest control company using approved soil termiticides at the manufacturer's dilution, issuing a treatment report or certificate for the owner to keep.
Can termites be treated after the villa is finished?
Yes, by injecting around and under the building, but it is harder, less complete and may mean drilling through floors. Treating before the foundations is far more effective.
