Site survey and flood test on every job

Waterproofing Services in Karachi: Roof, Water Tank, Bathroom & Heat Proofing

Roof, water tank, bathroom and basement waterproofing across Karachi, with roof heat proofing in the same visit. Site survey first, flood test before handover.

Cross-section of a Karachi RCC roof showing the layers of a waterproofing and heat-proofing system 1 · Reflective heat-proof top coat Room below stays drier and cooler 2 · Waterproof membrane 3 · Crack & joint repair 4 · RCC roof slab
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We waterproof roofs, water tanks, bathrooms, basements and walls across Karachi, and we heat-proof roofs in the same visit. Every job starts with a site survey to find where the water actually enters, because in Karachi the stain on the ceiling is rarely under the crack that causes it. The system we apply depends on the surface, not on a fixed package, and each job ends with a flood test before we hand it back.

This page covers every waterproofing service we offer, how each one works, which material suits which surface, and what to expect on price and warranty. I am Saad Danish, founder of Nest Fumigation Services. Our crews already work on Karachi rooftops and in its tanks every week for water tank cleaning and termite proofing.

Why Karachi roofs leak: dry for nine months, then a monsoon in a few weeks

A Karachi roof does not wear out from steady rain. It fails from the opposite: months of fierce sun and heat, followed by a short, heavy monsoon that arrives all at once. Through the summer the flat RCC slab expands every afternoon and contracts every night. That daily movement opens hairline cracks along the parapet, around water-tank bases and at every pipe that passes through the slab. Nothing leaks while the weather stays dry, so the cracks go unnoticed. Then the first heavy rain of July or August fills them in a single afternoon.

Most older Karachi homes also carry a traditional layer on the roof: a bed of mud or screed with brick tiles on top, laid years ago for heat. When that layer cracks, it holds water like a sponge and feeds it slowly into the slab for days after the rain stops. That is why a ceiling can keep dripping long after the sky has cleared, and why simply painting the top of the tiles rarely fixes it.

Near the coast, in DHA, Clifton and Karsaz, salt-laden air adds a second problem. Once moisture reaches the steel inside the slab, the steel rusts, swells and pushes the concrete off from below. Waterproofing early is far cheaper than repairing spalled concrete later.

1

Daily heat cycling

The slab expands every afternoon and contracts every night, opening hairline cracks at parapets, tank bases and pipe entries.

2

The old mud and brick-tile layer

Laid years ago for heat. Once cracked, it holds rain like a sponge and feeds it into the slab for days.

3

Salt air near the coast

In DHA, Clifton and Karsaz, moisture that reaches the steel makes it rust, swell and push the concrete off.

Every waterproofing service we offer

Nine services, one team. Pick the problem you have; each card says where it applies and how we fix it.

Roof waterproofing

Where
RCC flat roofs, terraces, balconies
Solves
Ceiling leaks, damp patches, monsoon seepage

We clean the roof, open and fill the cracks, treat the corners where the slab meets the parapet, and then apply a waterproof membrane across the whole surface, turned up the parapet wall so water cannot get behind it. On roofs that still carry the old mud and brick-tile layer, we survey first to decide whether the tiles can be sealed over or must come off. Sealing over a layer that is already saturated traps the water underneath, so we will tell you if removal is the honest answer.

Roof heat proofing

Where
Top-floor roofs
Solves
Heat coming through the slab into the room below

Heat proofing and waterproofing solve different problems, but on a Karachi roof they are best done together. Heat proofing uses a light-coloured, reflective top coat that sends much of the sun's energy back before it soaks into the slab, so the room below stays cooler and air conditioning works less hard. Applied over a waterproof membrane, it also shields that membrane from the ultraviolet light that ages it. Doing both in one visit means one surface preparation and one set of curing days instead of two.

Water tank waterproofing

Where
Underground sumps, overhead RCC tanks
Solves
Leaking tanks, water loss, contamination from outside

A leaking underground sump loses water you have paid a tanker for, and a crack that lets water out can also let ground water and sewage seepage in. We empty and clean the tank, repair cracks and joints, and line the inside with a coating approved for drinking-water contact, so nothing in the lining leaches into the water you store. We often combine this with underground tank cleaning, since the tank has to be emptied for both. For larger sites we treat tanks under our commercial water tank programme.

Bathroom and kitchen leakage repair

Where
Wet areas, floor joints, pipe entries
Solves
Leaks into the room or flat below

In Karachi flats, a leak in one bathroom becomes the neighbour's ceiling problem below. The water usually escapes through failed grout, the joint where the floor meets the wall, or around the drain and pipe entries. Where we can, we treat leaks without breaking the tiles, by sealing joints and injecting the gaps. Where the waterproof layer under the tiles has failed completely, we explain why the floor has to be opened, and we waterproof the bare floor and the lower walls before it is tiled again.

Basement waterproofing

Where
Basements, underground parking, lift pits
Solves
Ground water and seepage through walls and floor

Basements, underground parking and lift pits sit below the water table in parts of Karachi, so water pushes in from the soil side. We seal active leaks first, then apply a cement-based waterproofing that bonds into the concrete and works against water pressure from outside. It is the right system where the outside face of the wall can no longer be reached.

Wall seepage and damp proofing

Where
External walls, plinth level
Solves
Rising damp, peeling paint, salt marks

Paint that bubbles at the bottom of a wall, white salt marks, and plaster that crumbles at plinth level all point to rising damp or seepage from outside. We find the source first, whether that is a broken damp-proof course, a leaking pipe in the wall, or rain driving into the outer face, and treat that source rather than repainting over the symptom.

Expansion joint and crack sealing

Where
Building joints, slab cracks
Solves
Water entering through moving joints

Large buildings are built with joints that let sections move. Those joints are a common leak point when the original sealant hardens and splits. We cut out the failed material and refill the joint with a flexible sealant that stretches as the building moves, and we seal structural cracks in slabs and walls the same way.

Metal and sheet roof waterproofing

Where
Factories, warehouses, sheds
Solves
Leaks at sheet overlaps, bolts and gutters

Factory and warehouse roofs leak at the overlaps between sheets, at every bolt, and along gutters. We seal the laps and fixings and coat the roof with a flexible system made for metal, which also reflects heat away from the floor below. For warehouses we already treat for pests, this can be scheduled around the same visit.

Pre-construction waterproofing

Where
New buildings, foundations
Solves
Moisture protection built in before walls go up

The cheapest time to waterproof is before a building is finished. At foundation and slab stage we apply waterproofing to surfaces that will be impossible to reach later. Builders and owners who already book our pre-construction termite proofing can schedule both at the same stage of the build.

Which waterproofing material suits which surface

There is no single best waterproofing product. Each material has a surface it suits and a place where it fails.

Material Best for Strength Limitation
Acrylic elastomeric coating Roofs, heat proofing Flexible, reflective, water-based, no strong smell Needs re-coating sooner than heavier systems
Polyurethane (PU) liquid membrane Roofs, terraces, balconies Very flexible, seamless, bridges hairline cracks Some grades need a UV-protective top coat
Bitumen membrane Large flat roofs, basements Thick, tough, long-lasting Black surface absorbs heat unless top-coated
Cement-based waterproofing Water tanks, basements, bathrooms Bonds into concrete, works against water pressure Rigid, so it cannot move with cracks on its own
Flexible joint sealant Expansion joints, pipe entries, cracks Stretches as the building moves Joints only, not a full-surface system

How a waterproofing job runs, step by step

  1. 1

    Site survey

    We inspect the roof, tank or wet area and trace the leak from the stain back to its entry point. You get a written scope and quote.

  2. 2

    Leak test

    Where the source is unclear, we flood the suspect area or test it in sections to confirm where the water gets in.

  3. 3

    Surface preparation

    Cleaning, removing loose material, opening and filling cracks, and treating corners and joints. Most failed waterproofing fails here, so we do not shorten this step.

  4. 4

    Application

    The chosen system in the required number of coats, turned up walls and around every pipe and drain.

  5. 5

    Curing

    The system is left to set fully before it takes foot traffic or water. We tell you how many days before we start.

  6. 6

    Flood test

    On roofs and wet areas we hold water on the treated surface before handover, so a leak shows up while we are still there, not at the next monsoon.

When to waterproof in Karachi

  • Mar to May: waterproofing and heat proofing, before the heat
  • June: last dry weeks before the monsoon
  • Jul to Sep: emergency leak repairs during and after the rains
  • Oct to Feb: off-season, easiest to schedule

The best time is March to June, before the monsoon and while the weather is dry. Coatings need dry surfaces and several dry days to cure, and booking early avoids the rush once the rains start. Heat proofing is most worth doing before the hottest months, from March to May.

We also handle emergency leak repairs during and after the rains, from July to September. Some permanent work has to wait for the roof to dry out, but we can stop the immediate damage and schedule the full treatment for the first dry spell.

Waterproofing price in Karachi

Every waterproofing job is quoted after a site survey. The price depends on the area in square feet, the system used, the number of coats, and how much repair the surface needs before coating. A roof with a saturated brick-tile layer that must be removed costs more than a clean slab. The survey is how we avoid quoting for the wrong job.

  • Area in square feet
  • System and number of coats
  • Repair needed before coating
  • Access, height and roof condition

Warranty

Warranty terms depend on the system we apply and the condition of the surface, and we confirm them with your quote. If a treated area leaks within the warranty period, we come back and repair it.

Areas we serve

  • DHA Phases 1 to 8
  • Clifton
  • Karsaz
  • PECHS
  • Bahadurabad
  • Gulshan-e-Iqbal
  • Gulistan-e-Jauhar
  • North Nazimabad
  • KDA Scheme 1
  • Bahria Town Karachi
  • Cantt
  • Defence-forces societies
  • Korangi Industrial Area
  • SITE
  • Port Qasim

We waterproof homes, flats and commercial buildings across Karachi, including DHA Phases 1 to 8, Clifton, Karsaz, PECHS, Bahadurabad, Gulshan-e-Iqbal, Gulistan-e-Jauhar, North Nazimabad, KDA Scheme 1, Bahria Town Karachi, Cantt and the defence-forces societies. For factory and warehouse roofs, we work across Korangi, SITE and Port Qasim industrial areas.

Frequently asked questions

How much does roof waterproofing cost in Karachi?

Roof waterproofing in Karachi is priced per square foot, and the rate depends on the system used and the condition of the roof. We quote every job after a site survey, because a roof that needs its old brick-tile layer removed costs more than a clean slab.

What is the best time to waterproof a roof in Karachi?

The best time is March to June, before the monsoon. Waterproofing needs a dry surface and several dry days to cure properly. During the rains we can carry out emergency repairs to stop active leaks, and complete the full treatment once the roof dries out.

Is heat proofing the same as waterproofing?

No. Waterproofing stops water entering the roof. Heat proofing reflects the sun's heat so less of it reaches the room below. In Karachi we recommend doing both together: the reflective heat-proofing coat protects the waterproof layer from the sun and helps it last longer, and both need the same surface preparation.

Can you waterproof a roof without removing the old tiles?

Often, yes. If the brick tiles and the layer beneath them are sound and dry, we can seal over them. If that layer is cracked and holding water, sealing over it traps moisture against the slab, so the tiles need to come off first. The site survey tells us which case your roof is.

Is water tank waterproofing safe for drinking water?

Yes, when the right coating is used. Inside drinking-water tanks we apply a lining approved for potable-water contact and allow it to cure fully before the tank is refilled. We also clean and disinfect the tank as part of the job, so it goes back into use clean.

How long does waterproofing last?

That depends on the system and on how the surface is used. Lighter coatings need re-coating sooner than heavy membranes, and roofs that are walked on or carry equipment wear faster. We tell you the expected life of the system we recommend before you book.

Not sure what is causing the leak?

Call or WhatsApp +92-311-1101810, or contact us to book a site survey. We are open Monday to Saturday, 09:00 to 21:00. Tell us what is leaking and where, and send a photo of the stain if you can. It helps us bring the right equipment on the first visit.

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