Waterproof A Wall

How do you waterproof a wall?

Whether you are constructing a house or are planning to renovate it, you should think about ways to waterproof your walls and protect them from moisture.

This is especially important for those who live in the areas that receive a lot of rainfall or experience extreme humidity, as these weather conditions can cause your walls to stay damp for a long time and cause moisture to travel through the layer of paint and affect the internal structure. Not only will it make your house look ugly, but it can also lead to mould infestation and cause irreparable structural damage. This can threaten the foundation of your home.

Therefore, if you don’t want to spend big bucks and a significant amount of time fixing your home, consider waterproofing your walls to avoid any such trouble. Although there are several ways to waterproof a wall, it is advisable to hire a professional to take care of the problem instead of going the DIY-route and ending up with a home improvement disaster that could be much more expensive and time-consuming to fix.

While the arrival of the monsoon season may bring relief to many, for house owners, it is the 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 precaution 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.

At Hitch Property Constructions, we offer the best range waterproofing services to rectify your water issues. 

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 the 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 tradesman who will work logically through the symptoms of a problem and accurately identifying the cause rather than taking the easy way out and treating the first thing he sees.

Waterproof A Wall

How to Waterproof Your Walls – A Step-by-step Guide

Check for any cracks in the walls and seal them.

Over time, your walls can develop cracks, and these crack 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, and it is 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 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, and 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 itself 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 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 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 which blocks water and offers excellent waterproofing.

The Dos and Don’ts of Waterproofing Basement Walls

DO determine the source of the water.

Because concrete is porous, you can often see wet streaks that let you know where the water is coming in. Look for streaks along cracks, at the corners of windows, between mortar joints (for cement block walls), and around pipes where they enter or exits, such as a water supply line or a sewer pipe.

If entire wall surfaces are wet, however, you’ll need to do further sleuthing. To conduct a simple condensation test, dry an area of the wall with a rag and then attach a one-foot square piece of aluminium foil to the wall with duct tape. Peel off the foil after 24 hours and check how the underside of the foil feels. If it is wet, water is seeping through the wall from the outside. If dry, the moisture is originating elsewhere in the basement, most likely from a basement shower—easily remedied by installing a vent fan in the bathroom to direct steam outdoors.

DON’T make wall repairs with standing water in the basement.

During a rainy season, a crack in a basement wall can allow an inch or two of water in, but before you seek to repair the crack, remove all the water from the floor. Working in a flooding basement increases the risk of electrical shock or electrocution. Turn off the power to the basement, and then use a utility pump (with extension cords that reaches an upstairs outlet) to get rid of the water. The pump will discharge the water to the surface of your yard via a garden hose. When the basement is water-free, proceed with inspecting, fixing, and effectively waterproofing the basement walls.

DO fill cracks with hydraulic cement.

Another area where cracks are commonly found is at the bottom of the basement walls. When a foundation is poured, it’s footing—a wide flat base made from concrete and reinforced steel, designed to support the walls—is poured first, and then the walls are poured on top after footings harden. Although this is standard construction procedure, it can create what’s known as a “cold joint,” a weak spot in the foundation between the wall and the footing where cracks can develop with the shifting and settling of a foundation, along with lateral pressure from the soil.

Fortunately, sealing cracks is a relatively simple DIY task that involves filling them with hydraulic cement, such as QUIKRETE’s Hydraulic Water-Stop Cement (available from Home Depot). Hydraulic cement—which contains additives that cause the cement to expand and set rapidly—is mixed with water to a heavy putty consistency and then pressed into cracks with gloved fingers or with a putty knife (follow mixing and application directions). As hydraulic cement expands, it pushes deep into cracks and crevices to form a watertight bond. Mix only as much as you can use within three minutes, though, because that’s how quickly it begins to set.

DON’T forget to address window well leaks.

Window wells are a common source of basement wall leaks because they tend to retain water if a proper drainage system wasn’t installed beneath the well when the house was built. This can lead to water pooling around the bottom of a basement window and then seeping in.

While it’s difficult to install a window well drainage system after the fact, consider digging approximately two feet lower in the good area, and then filling the space with gravel to help rainwater disperse rather than collect in the window well. Then, caulk around the window with a caulk suitable for use on masonries, such as GE’s 100 Percent Silicone Window and Door Caulk (available from Home Depot). Besides, install a sloped window well cover, such as Shape Product’s Universal Fit Polycarbonate Window Well Cover (available from Home Depot), over the window to direct rainwater away.

Looking for the best waterproofing company? Look no further! Hitch Property Constructions has you covered. 

DO apply a masonry waterproofing product to bare interior basement walls.

If your foil test showed that water is soaking through your basement walls and leaving them wet, seal the interior of the walls with high-quality waterproof paint, such as DRYLOK White Extreme Waterproofer (available from Home Depot). This type of sealant comes premixed and goes on just like a coat of paint. When waterproofing basement walls with it, brush or roll the paint on thickly enough to fill all the little surface holes, then allow it to dry fully before a second coat is applied. When completely dry, the sealant forms a watertight bond to keep any more moisture from seeping through. A five-gallon container treats approximately 500 square feet of wall.

DON’T apply a sealer over painted walls or efflorescence.

If you or a previous owner painted the basement walls, you’d have to remove the paint before applying a sealer, which only adheres well to bare masonry. It’s common to find several coats of paint in older homes, which is best removed with a sandblaster by pros known as blasting contractors. Alternately, it can be removed by wire brushing, a tedious but inexpensive DIY task.

It’s also necessary to remove efflorescence—white deposits that form on the surface of concrete walls subject to constant moisture—before applying sealer; do so with muriatic acid (follow the manufacturer’s instructions).

DO take steps to keep water away from your basement.

Sometimes, the solution to wet basement walls is easy. For instance, remove foundation plantings, such as bushes and flowerbeds that require watering, which subsequently allows water to seep into the basement. Also inspect and, if needed, repair guttering and downspouts to ensure that they’re directing water away from your home. It’s also a good idea to grade your yard away from the foundation—at least a two per cent slope.

In addition to the above steps, consider having an exterior drain tile system installed. This is usually a last-ditch effort because it’s pricey, easily running $10,000 or more. It requires excavating the soil from around the outside of your basement to install a perforated drain at the footing level. A waterproof membrane is often installed on the outside of the basement wall, and the system also requires putting in a buried sump pump where water will collect and then be pumped to the surface. This is strictly a job for a foundation contractor, but it could greatly reduce basement water problems.

DON’T forget interior drainage solutions.

Another method of attaining dry basement walls is to install a drainage channel beneath the floor inside the basement. The drain is similar to the exterior drain tile described above, but it’s located just inside the basement walls; then, new walls are built on the inside of the drain, so the original basement walls are not visible. This is another job for a foundation contractor, at a minimum cost of around $5,000. When it’s done, you’ll have new, dry walls, and any residual water that seeps through the old basement walls will be directed to the drain channel and pumped away.

How do we stop water getting into walls?

So we have water in a wall, how do we deal with?

First, check into a detoxication 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 for all living things (including cats) and acceptance of 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 checks 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 form 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 in the inside, and 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. In Australia, 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 first 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 in a windy place, 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 getting in. Take particular note of any cracks in the wall which will need special treatment, we’ll come to that in a minute.

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 damp. This is very common in Bali where damp proof courses are not installed, but it can be fixed if you are know-how. Like poaching an egg, this is not something you would trust to 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 sloof and will stop water rising inside the wall from the ground beneath. Techniques widely marketed in Britain (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 batako blocks in the walls.

We have a huge range of waterproofing services Melbourne at Hitch Property Constructions that offers stress-free services for any water problem you got! 

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.

The golden rule in waterproofing is to stop water from getting in and not to try and 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.

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