A school deep clean is a scheduling problem wearing a cleaning problem’s clothes. The work itself is not exotic — washrooms, floors, canteen, high-touch surfaces, but it has to be delivered inside a fixed break, across a building with more washroom fixtures than most offices, and it has to be finished. Not mostly finished. On the first morning of term four hundred children walk in, and there is no version of “we’ll come back next weekend”. That deadline shapes every decision below. This page sits under our broader commercial cleaning service.
Planning backwards from the first day of term
We plan a school clean the way you would plan a shutdown: from the handover date backwards, with a buffer, and with the crew sized to the calendar rather than the calendar stretched to the crew.
The windows in Karachi are the long summer break, the winter break around late December, the Eid holidays, and mid-term breaks of two to five days. Only the first two are long enough for a full-building programme. A typical medium school — forty to sixty classrooms, fifty to eighty washroom fixtures, a canteen, two or three labs, a library, staff rooms, a hall and the corridors and stairwells connecting them — is around six to nine working days for a crew of eight to twelve. Which means a ten-day break is comfortable, a seven-day break is tight, and a four-day mid-term break is enough for washrooms, canteen and high-touch surfaces but not for floors.
Two rules follow, and we hold both of them.
The last day of the break is a buffer, not a working day. It is for the walk-through with your admin, the snag list, and the fixing of the snag list. A schedule that uses every available day has no room for the water going off, a delayed handover of a locked block, or a floor that has not cured, and one of those three happens on most jobs.
If the break is shorter than the scope, we cut the scope rather than the standard. We would rather clean the washroom banks, canteen and ground floor properly and tell you the first floor is deferred to the next break, than do the whole building at half depth and hand you a school that smells of wet mop on Monday. That conversation happens at the quote stage, in writing, not on the last afternoon.
Cleaning first, disinfection second, and why the order is not negotiable
Since 2020 a lot of schools have been sold “sanitisation” as a standalone product: a crew arrives, fogs or sprays disinfectant through the building, issues a certificate, leaves. On a soiled surface that is close to a placebo, and the reason is chemistry rather than opinion.
Disinfectants are consumed by organic matter. Sodium hypochlorite reacts with proteins, dust, food residue and body soil, so a solution applied over a dirty surface is largely spent oxidising the soil before it reaches anything living underneath. Quaternary ammonium compounds have a different failure mode with the same result — they are cationic, so they are deactivated by anionic detergent residue and by hard water, and Karachi’s water is hard. Either way, soil is a physical shield: a bacterial or viral particle sitting under a film of grease and dust is simply not in contact with the chemical.
The second half of the same point is dwell time. Every disinfectant has a label contact time — typically five to ten minutes for the concentrations used in schools — during which the surface must remain visibly wet. A crew that sprays and immediately wipes dry has applied a cosmetic. So our sequence on every surface is: detergent clean to remove the soil, rinse, then disinfect and leave wet for the full label dwell, then allow to air-dry or wipe only after the time has elapsed.
The honest consequence for your budget: a school that has been genuinely deep cleaned and that maintains daily high-touch wiping in term time does not need monthly fogging. If you are paying for both, the recurring fog is the line item to cut. Spend it on the daily routine instead, which is where the actual transmission control happens.
Child-safety chemistry: what we use and what we refuse
A school is not an office with smaller chairs. Children put hands on floors, on skirtings, on stair spindles and then in their mouths; some of them are asthmatic; and the youngest are physically closer to any residue on a low surface. So the product list is deliberately narrower than it would be on a commercial site.
What we use. Neutral pH detergents for the bulk of the cleaning, which is most of the job. Hydrogen peroxide based disinfectants, which break down to water and oxygen and leave nothing behind. Benzalkonium chloride at label dilution on high-touch surfaces and canteen food-contact surfaces, thoroughly rinsed where food is prepared. Citric acid descaler on washroom limescale. Seventy percent isopropyl alcohol on IT and lab electronics. Alkaline degreaser in the canteen, kept in the canteen.
What we will not use in a school. Phenolic disinfectants — the heavy pine-smelling type still common in institutional cleaning here, because they are not appropriate around young children and they leave a persistent residue. Strong solvent cleaners in classrooms. Heavy synthetic fragrance used to signal cleanliness, because a strong smell is not evidence of a clean surface and it is a genuine problem for asthmatic pupils. And we will not mix an acid descaler with a hypochlorite product, in the same bucket or on the same surface in sequence, because that combination releases chlorine gas — this is the most common serious chemical accident in institutional cleaning anywhere, and it is why our washroom crews carry pre-diluted products with colour-coded bottles rather than concentrates to be mixed on site.
On pest treatment during a break. Where treatment is part of the programme, residual products have a re-entry interval on the label and we observe it against the day children return, not against the day we finish. If that means we cannot treat a block on the final day of the break, we move it to the next break or use a bait-based approach with no re-entry requirement. This costs us scheduling flexibility and we do it anyway. See school pest control.
The washroom banks are the job
If a parent forms an opinion about a school’s hygiene, it is formed in the washroom, and it is the zone that a term-time crew can only ever service rather than restore. It also takes the largest share of the hours.
The work is: descaling every fixture with citric acid, because Karachi’s hard water leaves a scale layer that is itself porous and holds soil; urinal traps and cartridges removed, cleaned or replaced, since a urinal smell is almost always uric scale in the trap and pipe rather than a surface problem that mopping can reach; floor gullies lifted and cleared; grout scrubbed and, where it is failing, flagged for regrouting rather than cleaned repeatedly; cisterns, flush plates, taps and hand-dryer housings; partitions, door furniture and extract grilles; mirrors and ledges last.
One small thing worth doing yourself at the end of every break: pour a jug of water into every floor trap and every unused washroom’s drain. A trap that has dried out over a long summer break stops sealing, and an unsealed trap is both where the drain smell on the first morning comes from and the route by which large cockroaches appear in a washroom that was spotless the week before.
Overhead and underground water tanks belong in the same break. A school tank feeding washrooms, drinking points and the canteen should be cleaned and disinfected on a schedule, and the break is the only time the supply can be taken down without disruption. See commercial water tank cleaning.
Canteen, classrooms and floors
Canteen and tuck shop. Treated as a commercial kitchen, not as a room with a counter: hood and filter degreasing, the gap behind and under the fridge and cooker where spilled food accumulates, dry-store shelving emptied and cleaned, bins and the bin area, and food-contact surfaces degreased and rinsed before sanitising. This is also the highest-value pest intervention in the building, because it is where the food is. The method detail is the same one we use on kitchen deep cleaning and on restaurant sites.
Classrooms. Desks and chairs turned and cleaned including the undersides and the gum on them, which is a genuine time sink and has to be scraped cold. Whiteboards, ledges, cupboard tops, fan blades, light diffusers, window tracks, grilles and door tops. High-touch points — handles, switches, handrails, water cooler taps and push buttons — cleaned, then disinfected with full dwell.
Labs, library and hall. Bench cleaning around fixed equipment, fume cupboard exteriors and sink traps, with chemical storage left entirely to your lab staff; library shelving, tops and floors; and the high-level dusting in halls and stairwells that nobody does in term time.
Floors, and why they go early in the break. Terrazzo, marble, PVC and vinyl all behave differently, and where a floor needs stripping and resealing, the polymer needs cure time before furniture goes back onto it — a floor that is walked on or loaded too early marks permanently. So floor restoration is scheduled in the first half of the break, never the last two days. Corridors and stairwells are done in sections so that access through the building is maintained for your own staff and any maintenance contractors, who are usually working the same week we are.
Access, sequencing and working alongside your maintenance
The most common way a break goes wrong is not cleaning-related. It is that painting, carpentry, tile replacement, AC servicing and cleaning are all booked into the same ten days without an order.
Cleaning goes last. Every dust-making trade — painting, drilling, tiling, ceiling work, AC filter and duct servicing — must finish before we start a block, or the block gets cleaned twice and you pay for it twice. Where the calendar cannot allow that, we sequence by block: paint the upper floor while we clean the ground floor, then swap. We ask for keys and access to every room including the ones nobody has opened since last year, a nominated person from admin available each day, and confirmation that water and power will be on throughout, which on a Karachi campus in a break is worth asking rather than assuming.
Handover is a walk of the building with your admin lead against the written scope, a snag list agreed on the spot, and the snags cleared on the buffer day.
Pricing
School deep cleaning is quoted per site after a walk-through. There is no honest published per-square-foot number for this work, because the hours are driven by fixture count and washroom condition far more than by floor area — two schools of identical size can differ by half again. The walk-through produces a fixed quote, a written scope by block, a day-by-day schedule against your break dates, and a crew size.
Pest control for schools is contracted annually and we do publish those bands: PKR 60,000 to PKR 240,000 per year depending on campus size, visit frequency and scope, which is the same structure we use for restaurants and clinics. Campuses in Bahria Town carry a flat PKR 800 fuel surcharge per visit, waived on contracts of three or more visits. Most schools run cleaning and pest on one contract so that the break-time scheduling is handled once.
Booking
Send us your break dates first — that single detail decides whether the scope is the whole campus or a prioritised part of it. WhatsApp +92-311-1101810 or email contact@nestfumigationservices.com with the dates, the number of classrooms and washroom fixtures, whether there is a canteen, and your campus location. Book early: every school in Karachi wants the same ten days, and the long summer and winter breaks fill months ahead.
Common questions
Can you deep clean during term time?
Only in parts, and only zones that can be closed — a washroom bank taken out of service for a day, the canteen over a weekend, a block on a Sunday. Floor restoration, high-level work over occupied classrooms and anything requiring dwell time or cure time need the building empty. Full-campus work belongs in a break.
How long does a school deep clean take?
Six to nine working days for a medium campus with a crew of eight to twelve, plus a buffer day. Larger campuses scale by crew size rather than by days, because the break length is fixed and cannot be negotiated with.
Do we need monthly disinfection or fogging?
Generally no, and we will say so rather than sell it. Disinfectant works on a cleaned surface with full contact time; applied over soil it is largely consumed before it does anything. A proper deep clean each break, plus disciplined daily wiping of high-touch points in term time, does more than a recurring fog. Fogging has a place during a live outbreak, not as a routine.
Are the chemicals safe for children?
The list is deliberately restricted: neutral detergents, hydrogen peroxide disinfectants, benzalkonium chloride at label dilution, citric acid descaler, isopropyl alcohol on electronics. We do not use phenolic disinfectants or heavy fragrance in schools, we never combine acid descaler with hypochlorite, and all products are supplied pre-diluted with safety data sheets provided to your admin office.
Do you also handle pest control for the campus?
Yes, and the break is the right window for both. Cleaning removes the food source — canteen grease, spillage in dry stores, debris under fixed furniture, and treatment deals with the population, in that order. Re-entry intervals are measured against the day pupils return. See school pest control and commercial pest control.
Book school deep cleaning in Karachi
Call or WhatsApp +92-311-1101810, or email contact@nestfumigationservices.com. Our office is at Plot #14, 2/1 2nd Gizri Street, DHA Phase 4, Karachi 75500, open Mon-Sat 09:30-20:00. Nest Fumigation Services Private Limited is ISO 9001:2015 certified and a member of KCCI, SPMA and PPMA. See also commercial cleaning, school pest control, kitchen deep cleaning and commercial water tank cleaning.
Saad Danish is a co-founder and director of Nest Fumigation Services Private Limited, a licensed pest-control and fumigation company based in DHA Phase 4, Karachi. He oversees the company's administration, client services, and marketing, working alongside NFS's technical team to deliver residential and commercial pest management across Karachi — from termite proofing and general pest control to HACCP and Sindh Food Authority compliance programmes for food, warehouse, and industrial clients. Nest Fumigation Services is ISO 9001:2015 certified and a member of the SPMA (Sindh Pest Management Association), PPMA, and the Karachi Chamber of Commerce and Industry.
More about our team →