How Do You Waterproof A Wall?

how do you waterproof a wall (3)

Waterproofing. We’ve heard it so many times when it comes down to it, but most of us are yet to know what exactly its function is, where it should be done, and what are the best options available. That’s why in this article we’re going to cover all the essential points you need to know about waterproofing your walls.

Dampness or leaking walls is a problem most of us are familiar with in Indian households. Whether it’s in bathroom ceilings, wall areas conjoined with the bathroom, or even some tricky spots on other walls, you must’ve seen big patches of dampness appear. Sometimes, the spotted green fungus also appears, and the paint on your wall tends to peel off.

This problem is especially aggravated during the rainy season and can give a depressing look to your house. Moreover, dampness also creates the perfect environment to foster mould, fungus and bacteria and can have detrimental effects on your health in the long run. Finding the right duplex build is an important decision. Check out our range of the best home design constructions at Hitch Property Constructions.

Waterproof Your Walls – A Step-by-step Guide

While the arrival of the monsoon season may bring relief to many, for house owners, it is time to prepare and protect their homes from water leakage. During this season, your exterior walls get exposed to rainwater frequently. When exterior walls get exposed to rainwater or high humidity, water and moisture can travel through and affect your internal walls. This means that your walls may stay damp for a long time before drying. 

So, your wall becomes a breeding ground for mould and mildew growth, causing irreparable damage and water leakage. So, if you prepare or take precautionary steps to waterproof your building before heavy rainfall, you can keep your house safe and enjoy the beauty of rainfall. Here are a few tips to prevent dampness and waterproof your walls.

Check for any cracks in the walls and seal them.

old concrete cracked wall texture

Over time, your walls can develop cracks. These cracks generally start from the weakest area of the wall. To install a door or a window, the builder adds extra framing to your walls. Hence these areas are still weaker than the rest of the wall, where the cracks start developing. 

As a result of these cracks, moisture gets into your structure and creates damp patches in your walls. Thus, it is important to remove these cracks with suitable putty. Make sure you do this before the monsoon to prevent water leakage.

Exterior Paint

When painting the outside of your home, keep in mind that there are two main purposes for your exterior paint. The first is obvious. You expect your paint should make your home pleasing and give it visual appeal. While this is important for you, there is another use for exterior paint, and that is to provide an outer barrier for your home. Whether you’re painting on wood, vinyl, metal, or stone, the right paint offers the first line of defence from outside elements such as water. Find out which paint is best for waterproofing your home and use it with suitable undercoating.


One of the key areas in your home where drafts can enter or warm air can escape around the windows. Once your windows get old, they will lose the seal both in the windows themselves and around the frame. If you can’t purchase new windows, it’s a good idea to re-caulk around the frame. Quality caulking with professional installation is generally 5-7 years, so make sure you don’t use cheap products. 

Other areas where caulking can help you are around your bathroom. Check around the sink, particularly underneath the counter, shower, and around the tub. Wherever there are fixtures in your home, there is generally caulk used to seal them.

Waterproofing During Construction

Waterproofing is best done at the time of construction. Using a high-quality liquid waterproofing compound in the starting stage with cement and sand can be effective. Otherwise, use a waterproof coating before painting your exterior walls to prevent water leakage. 

Nippon Paint’s Hydroshield Dampproof is a fibre-reinforced coating used for waterproofing; it forms a thick elastic film that blocks water and offers excellent waterproofing.

Now that you can safeguard your home by waterproofing, enjoy the torrential rains without any worries.

Golden rule – stop the water from getting in.

The golden rule in waterproofing is to stop water from getting in and not stop it from getting out. This sounds pretty obvious, doesn’t it, but you’d be surprised at the number of even experienced builders who start trying to seal leaks from inside. Mind you, finding the point of entry may not be easy. Water can travel a long way through a structure or even saturate it completely, making finding the source a difficult task.

Why do we get leaks?

The walls of most buildings these days have reinforced concrete vertical columns with reinforced ring beams along the top that provide strength. The areas between the columns and beams have an infill of light concrete blocks or soft local red bricks with a skim of hard concrete on the surface. The reinforced concrete is often very poorly made with cracks and cavities in it, and the infill is like blotting paper (sorry, you might not remember that, like a sponge).

This sort of structure is very rigid, and the regular earthquakes we get in Bali (yes, we get lots, usually so small we don’t even notice them but now and again one that will wake you up in the night) and these regular ground movements result in cracks in structures usually through the walls of buildings.

It is also very rare to find a tradesperson who will work logically through the symptoms of a problem and accurately identify the cause rather than taking the easy way out and treating the first thing he sees.

How do we stop water from getting into walls?

So we have water in a wall, we have kicked the cat (repeatedly) and taken it to drink.

So how do we deal with it? 

First, check into a detoxification centre to deal with our alcoholic escapism. This will stop the DTs and the bloodshot eyes.

Next, check into an ashram. Take a nine-month course in transcendental meditation where we learn to love all living things (including cats) and accept the water issues in our lives.

Finally, get a shave and a soothing massage.

Now we can return home, apologies to the cat, hide the bottle of gin and start thinking about our wall.

First – find where the water is getting in.

As we all know, it is a basic law of nature that water flows downhill, so we start at the highest point.

Is the wall open to the elements at the top, or is the roof overhanging? If the roof is not overhanging, look along the top of the wall and check for cracks, even very fine cracks. Does the upper surface have a waterproof coating? Is there a concrete roof or a parapet wall? It may be that water is getting in where the concrete roof slab meets the wall or through the parapet wall and into the top of the wall below.

Leaks from cracked concrete roof gutters

A very common problem in Bali is leaking concrete gutters. It is regarded here that it is very bad to allow water from your roof to run off onto a neighbour’s property or into a street. If a building is built right against the property line, and very many are, then usually a concrete gutter is built along the top of the wall to catch water from the roof and take it away. These concrete gutters have two basic problems:

  • Ground movement often results in cracks across the gutter which allow water into the wall. If the cracks are small, this can be fairly easy to fix. The gutter must first be cleaned thoroughly then waterproofed on the inside. It is best to do the whole gutter while you are at it.
  • Wall gutters are often built with the outer wall higher than the inner wall so that if the gutter fills with water, it will overflow into your building either across the ceiling or down the inside of the wall. roof gutters are made of plastic or aluminium and purposely have the outer side of the gutter lower than the inner side, so if they fill up, they will overflow outwards. To solve this problem, firstly, make sure that the drain pipe from the gutter is large enough to take the roof area it has to drain and that the outer side of the gutter has low points cut in it to provide overflow points. These should, of course, be lower than the inner side of the gutter. It is also a good idea to make sure that downpipes have a gap between the gutter and the ground so that water cannot back up in the pipe.

Check the surfaces of the wall.

When you have checked along the top of the wall, next look at the surface of the wall. Carefully check it from top to bottom. Is it open to the weather? Note that if you are windy, the wind can drive rain at steep angles against the wall. Sensibly designed buildings have good roof overhangs, which are designed to keep the rain off the walls. Roof overhangs also keep sunshine off walls and so keep inside room temperatures down.

If you have a wall exposed to rain, you can waterproof it to stop water from getting in. Take particular note of any cracks in the wall which will need special treatment; we’ll come to that in a minute. Check out our range of Melbourne townhouse builders for your dream house.

A word of warning, a wall needs to breathe so that if water does get into it, it can evaporate out again. Do not waterproof both inside and outside surfaces of a wall. If you do, you may well always have damp walls.

Rising damp

The last thing to check for is rising dampness. This is very common in Bali, where damp proof courses are not installed, but they can be fixed if you are know-how. Like poaching an egg, this is not something you would trust people who don’t know what they are doing. 

The solution is to cut out a horizontal slit right through the bottom of the wall and the full length of the wall. Yes, this needs great care, and for obvious reasons, you don’t do it all at once. 

You then fill the slit with high-density cement. This is known as a spoof and will stop water from rising inside the wall from the ground beneath. Techniques widely marketed (usually of very dubious efficacy), such as injecting silicone solutions, are not available here. They would probably not work because of the high porosity of the Bamako blocks in the walls.

Sealing the leaks

Alright, so we have found the cause. How do we treat it? The traditional method is to use a skim of high-density waterproofing cement, but this is not a method I recommend. This type of waterproofing film is very brittle and can crack. On a surface exposed to sunshine, the excess surface heat will crack the concrete skim away from the wall beneath, allowing water to enter, which can travel between the concrete skim and the surface beneath.

My treatment of choice is a thick polymer paint applied with a brush. It comes in different colours. There are cheaper local versions, but I suspect you get what you pay for. Cracks need special treatment as they are likely to suffer further movement. 

Raintite comes with a membrane material, rather like a thick bandage. Paint the Raintite polymer along both sides of the crack, stick the bandage over the crack along its length, then paint the bandage to saturate it with the polymer fully. If the crack moves, the bandage will stretch a bit and maintain the waterproof film. It should be noted that these polymers do not like water.

Before applying a waterproofing polymer, the surface must be very clean and dry. Any loose paint, moss or dirt must be removed first, and the surface must be dry. Please wait for a day when the surface and any cracks have fully dried out before waterproofing it.

For general waterproofing of walls in good condition, Dulux Weathershield is the universally respected waterproof paint for outside walls but again, make sure the wall can breathe.

Now that we have dealt with the difficult stuff, we can move on to easier things like teaching a chimpanzee how to poach an egg.

It’s Possible To Waterproof Leaking Basements From The Inside

how do i stop water seeping in my basement walls (2)

Water and moisture considerably reduce the value of a basement as a living space or storage area. When moisture enters a basement, the conditions for the formation of mould become favourable. And once mould has formed, it continually produces spores. It releases them into the surrounding air, allowing them to spread through the rest of the building, which not only causes a musty smell but also reduces the living quality and even causes health disorders.

The cause of water or moisture in basements is usually groundwater or ground moisture which penetrates the basement through the floor slab or the basement walls. Such defects are frequently encountered in older buildings, but new buildings can also be affected.

Construction is usually carried out during the dry summer months, so designers, owners and artisans sometimes neglect the seasonal changes, which will expose a basement to water in the fall and winter. As a result, the waterproofing of new structures is often neglected and does not provide permanent protection.


A recent survey of leaking basements showed water comes from a variety of sources, but walls are the usual culprit:

  • Occurrence of moisture
  • Only on walls: 82.8 %
  • Only on the floor: 4.1 %
  • On walls and floor: 13.1 %

Moisture penetration on walls (Multiple entries were permitted)

  • Larger areas: 58 %
  • Around penetrations (pipes, cables, doors): 35 %
  • Cracks: 28 %
  • At the horizontal barrier: 27 %
  • At the wall/floor junction: 22 %
  • Other (partially multiple sources): 11 %

Moisture penetration on floors (Multiple entries were permitted)

  • Cracks: 55 %
  • Larger areas: 46 %
  • Other (partially multiple sources): 6 %

This survey examined mostly basements built of masonry. Leaking basements built with concrete walls tend to show less moisture penetration in large areas but more water-bearing cracks.

The focal point of waterproofing should be your bathroom. The reason is simple. It’s the place from where most of the water ingress occurs throughout the year. Any seepage from these surfaces can negatively impact your adjacent walls.

That being said, however, sometimes the damage is due to outside factors like rain or has already occurred before your bathroom was waterproofed properly. In such cases, it’s a great idea to waterproof the dampened walls in your rooms as well. Remember, in such cases. It is always better to get help, even if it’s late than never.

Finally, we have ceilings that may leak(this usually happens in bathrooms if your roof/ the bathroom above your floor hasn’t been waterproofed properly). You can also treat these with effective proofing. This will certainly save you a lot of trouble in the long run.


For new construction and most remedial waterproofing work, experts agree that the most effective waterproofing installation is on the positive (exterior) side of the structure. Finding the right Melbourne home builders is an important decision. Check out our range of the best home design constructions at MJS Construction Group.

However, negative-side applications do have their place. They’re effective as an emergency solution. a Macon-based waterproofer, says he’s encountered countless occasions when negative waterproofing emerges as the only option.

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