Like it?
Share it!

The Ultimate Guide to Understanding Waterproofing Problems in Your House

Frozen Water Connection

How do you react when you visit your basement after a gap of a few weeks only to find a strange green growth lacing your walls? You are understandably grossed out, until you lay your eyes on the discarded furniture. You see the green thing hasn’t spared it either. It has formed a thin carpet-like coating on your upholstered sofa, and is running down its wooden legs, spreading on the floor beneath. You are disgusted now. Petrified even.

What happened? This room was totally fine just a few weeks ago when you had last dumped your stuff in it.

Well, dampness happened. That’s what. It’s a common problem, though one never quite gets used to the sight of mildewed furniture. If you have a moisture problem in your building it’s unlikely you haven’t encountered it before. You may have played it down, but that gray-green thing now swarming your basement? That’s mildew on the wall which you cannot ignore.

Mildew is just one of the many things screaming at you that your house isn’t as waterproof as you thought it was. There are many other things conveying the same, but our aim isn’t to gross you out. It’s to drive home the point that good quality waterproofing is essential in residential and commercial buildings and why you must tackle the related problems as a matter of urgency.

What is waterproofing?

Waterproofing is the process through which one makes an object “virtually impervious to water.”

Waterproofing in construction terms alludes to stopping water, even moisture, from entering buildings.

Both waterproofing and moisture control are a part of a building’s construction but can be added as extra measures later on. A good waterproofing plan not just keeps water from penetrating buildings it also allows for proper drainage of the water that does manage to get inside the building.

Why is waterproofing important?

Waterproofing is important because it keeps a building dry, healthy, and safe for its inhabitants.

Inadequate waterproofing brings with it dampness, which in turn causes a number of problems. We spoke of the mildew earlier. Mildew is a type of mould, which doesn’t just look bad, stink to high heaven, and destroy your belongings, it is also unsafe to be around. It pollutes the air we breathe in and can bring on allergic reactions in sensitive individuals. It can worsen your asthma problem and in severe cases lead to vomiting, respiratory dysfunction, and liver damage.

Stagnant water also leads to a buildup of fungi. It can damage the property inside a building by causing it to rot. It can harm the walls as well. Water can even cause structural damage by weakening the foundation of a building. It can seep into the foundation walls and freeze there in cold weather, causing the wall to crack in places. This applies not just to wood but to concrete as well.

Waterproofing, therefore, is important to maintain the overall health of a building as well as that of its residents.

Waterproofing Problems in Buildings

measuring wall crack

A waterproofing problem can arise anywhere but typically it’s the roofs, the basements, and the exterior walls that show the most frequent signs of it. The parts of your house that are exposed to the elements are more likely to suffer the highest damage.

Let’s look at some of the most frequently encountered causes of waterproofing problems in buildings.

1) Foundation Wall Cracks

cracked brick wall
Image is provided by Johan Hansson via Flickr

The foundation is the most important part of a building, and unfortunately its biggest threat is water.

Water that comes down in the form of rain and snow, and also that which is present in the soil on the ground the building stands on.

Cracks in foundation walls can be attributed to a number of factors — poor construction, uneven ground on which the building stands, water seepage from the soil, soil expansion and contraction, and freeze-thaw weathering to name a few. This problem worsens with time as the weight of the building starts wearing the foundation down. Not just wooden structures but even those made of concrete and stone weaken with time. Water penetration can also cause concrete foundations to shrink over the years.

Not all cracks point to a serious problem but they can represent a waterproofing glitch. Each time you spot cracks in your walls, especially in the basement, you should have them examined. Non-structural cracks could point to a water infiltration problem. You won’t be able to tell the difference between structural and non-structural cracks, however. It’s best to have a professional take a look at them.

2) Sump Pump Problems

Repairing A Sump Pump In A Basement

A sump pump, as the name suggests, is a suction pump that collects water from a sump (a low space or a depression in the ground) and directs it to another location.

Its main purpose is to keep the area under a building dry. It does so by collecting water from the area surrounding the building and diverts it away from the foundation.

Sump pumps are usually installed in the lowest point of a building, typically in the basement, and are primarily responsible for keeping them dry. Sump pumps are installed at the time of construction in dedicated pits.

A sump pump failure is a big deal. Not only will it lead to a wet basement and a weakening foundation if ignored, fixing the problem and the resultant damage to your property will run into thousands of dollars.

Unfortunately, sump pump problems are hardly uncommon. The reasons could range from the pump being a faulty piece, it not being properly installed, it not being the right fit for your building, or it experiencing a switching failure. The pump could even freeze in extreme conditions if exposed outdoors. Hence, proper maintenance of a sump pump is crucial. Most people, however, install one and forget all about it, until they are greeted with a flooded basement, the cause of which they can’t even guess.

If your sump pump is used only once or twice a year, it may get clogged with debris in the meantime and may not run when the rain comes pouring down next. To avoid that from happening, run it periodically to check if it’s in a good working condition.

3) Faulty Roofs

Roofs can present as much of a waterproofing challenge as basements, especially in older houses that have experienced many rough seasons.

Roofs leak when the roofing membrane wears down. Flat roofs are more prone to leakage as opposed to sloping ones. Water accumulation on the roof can lead to moisture penetration into the ceiling below. This in turn can lead to a growth of mould, particularly in attics and closed spaces. Leaking roofs can also lead to electrical failures and structural damage.

Any cracks in your ceiling should be immediately paid attention to and if you spot even the slightest of dampness in your ceiling, have it examined without delay. If you allow matters to worsen, you will only end up with a bigger bill.

4) An Inefficient Drainage System

Poor drainage is another way for water to enter your home, the problem compounded during wet weather. If the water directed by eavestroughs into downspouts is drained near the foundation wall, it will lead to water accumulating in a sensitive and moisture-prone area. In case of heavy rains when a lot of water passes through the eavestroughs and falls on weeping tiles around the foundation, the result could be an overloading of your home’s drainage system.

Malfunctioning drains are never good news, and are also one of the biggest reasons for dampness, wetness, and other water-related problems in a property.

Types of Waterproofing

Delta MS & Blueskin Membranes for external waterproofing

Buildings are waterproofed at the time of construction, but for those facing a waterproofing problem, solutions can be implemented later on. The world of waterproofing types and products is vast, and it would be beyond the scope of this guide to delve deep into all the concerned aspects. We are, however, giving you a basic idea about the main types of waterproofing, along with our take on DIY waterproofing solutions.

Interior and Exterior Waterproofing

Waterproofing combats the ill effects of persistent humidity inside a building as well as the occasional flooding of a room, thus keeping your walls structurally sound and free of nasty fungi growth.

Interior waterproofing is a way to manage water or moisture that has already entered your living space. Some debate whether this process should even be called waterproofing as it involves moisture/water management as opposed to keeping it at bay. Interior waterproofing works with your drainage system to direct the accumulated water to a sump pump. It may involve installation of pipes and drains along the walls or under the foundation to collect the groundwater in the area and direct it away from the foundation to keep the basement and the walls dry.

Exterior waterproofing, on the other hand, involves waterproofing the exterior of your walls, which strikes at the root of the problem. This is typically more effective, extensive, and also more expensive than interior waterproofing.

As far as possible, opt for exterior waterproofing when faced with wet basements or damp walls. Go with interior waterproofing only when waterproofing your property from the outside is not a feasible option. What if you can’t afford that big bill? What if your basement is just awkwardly located? What if you share the damp walls with a neighbour and he is in no mood to let your start working on them?

Interior waterproofing can be considered as a solution when faced with minor leaks or non-structural cracks. This is a good system to drain out accumulated water in your basement, but will do nothing to fix the cause of the problem.

Roof Waterproofing

Roof waterproofing

Roofs are typically waterproofed by installing eavestroughs and downspouts to drain them of the rain water and melting snow. Things are not as straightforward with flat roofs, however, which are common in commercial buildings. Due to the flat nature of the surface, water tends to pool in places on it. It therefore becomes important to give the surface a slight slope to aid the movement of water in the desired direction and keep the surface dry.

Roofs are waterproofed by applying a waterproofing membrane on the surface. Care must be taken for the application to be extremely smooth; you don’t want pockets of water to emerge due to a rough or uneven coating.

This on its own is enough to prevent leaking roofs. But if you want to impart a slope to the surface to take away any possibility of water pooling on the roof, you will have to create another layer on the top of the surface.

This can be done using a filling material appropriate to be used on the roof. Lay on the material on the surface and once the desired slope is created, seal the material with tiles or a flooring of your choice.

Brick Waterproofing

This involves treating and sealing the brickwork in the parts that have been damaged due to dampness or water penetration. Apart from concrete and wood, moisture damages grout and bricks as well. Along with the moisture, soil and minerals also seep into brick constructions. In cold weather conditions like those witnessed in this part of Canada for most of the year, this moisture or water freezes, leading the bricks to expand, meaning pop. If you have ever wondered why bricks chip, or even crumble with time, this is your answer.

Dampness is also responsible for mould-laced brickwork, ruining the aesthetic appeal of your masonry.

Sealing the bricks proofs them against moisture and water, and thus keeps all of the above mentioned problems at bay.

Bricks are first cleaned up; they are rid of the fungi growth, stains, graffiti, and efflorescence.

Acids and OTC chemicals are available to fix this problem, but we recommend you not going down that path. The reason being that while the acids may cleanse the bricks and your stone masonry of ugly stains, they will also very likely damage them.

Water repellents and sealers are a better idea (and waterproofing agents are better than sealers).

  • Scrub the area clean of the accumulated dirt and dust, and fill in the cracks in the walls.
  • Apply a coating of your chosen waterproofing product to the surface in question. Let it settle for a few minutes and follow up with another, thicker coating.
  • A number of good waterproofing products are available in the market. If you want to waterproof your brickwork yourself, you might want to research on the best options available in this regard.
  • If you opt for a water repellent you may have to reapply the coating every few years, depending on the damage caused by the weather.

When it comes to sealing or waterproofing parts of your property, it is alright to tackle minor problems yourself. But for anything remotely serious or large in scope, we highly recommend giving a waterproofing company a call.

Fixing Your Basement Woes

Red bike in rainy day

Rains are awesome, except when they flood your basement.

Basements should be dry, period. And yet all too often they are wet or damp. And this isn’t confined to the rainy season either. Basements are notorious for being dark and dank, giving out a musty smell and a cheerless feel. The reason for this is a lack of ventilation and sunlight. Here are the most common basement-related problems that people encounter, along with suggestions on how you can combat them.

A Build-up of Moisture

Humidity or moisture can build up in a basement for a number of reasons. The rain water in the gutter outside didn’t drain completely. Water accumulated around your foundation walls during rains and as the snow melted.

Whatever the reason, you should take immediate steps to dehumidify your basement or it will lead to a growth of that cringeworthy thing called mould.

Accumulation of Water

If you have a driveway or a garden that slopes down into your house and towards your basement, you will likely face a wet basement problem throughout the year. This is because water will flow down the slope and settle around your basement not just when it rains or snows, but also when you water your garden or wash your driveway. Even a steady trickle of water will lead to soil saturation around your foundation, causing the moisture to seep into the basement.

During rains, storms, and snowfall this problem will worsen.

Clogged Roof Gutters

Removing Leaves from the Gutter

The main purpose of roof gutters and downspouts is to direct rain water and melted snow away from your foundation but when they get clogged due to debris such as leaves, twigs, and pebbles, the water may instead flow down the walls and settle on the area surrounding your foundation walls, instead of being driven away from them.

Wall Cracks

By now we know well that water doesn’t always make a grand entry into the house; most of the time it goes about its business quietly, seeping through the cracks in the walls. Keep an eye out on them cracks, and seal them sooner than later.

What you can do to keep your basement dry:

  • Try dehumidifiers to rid the space of high levels of humidity
  • Insulate cold surfaces
  • Heal all the basement cracks
  • Fix the sump pump problems
  • Attend to accumulated water immediately
  • Don’t let water accumulate around your foundation
  • Fix any broken/clogged rain gutters as well as all the plumbing leaks in your building
  • Extend downspouts to drive rain water further away from the foundation
  • Don’t store anything wet in the basement. Don’t even dry your clothes there.
  • Kill the mildew (this can be a DIY job, depending on your appetite for work!)
  • Check for water contamination around the building. Sewer lines running underneath the ground your house is built on can give off an extremely unpleasant smell during rains as well as lead to a buildup of moisture in your basement.
  • Examine your basement for any kind of damage (and not just the obvious kind) after every flooding episode. Spotting and repairing damage in time will save you a lot of grief later on.

In order to dry out a wet basement you need to first determine the root cause of it. Does the problem lie outside of your house or inside it? What exactly is the source of this dampness?

There’s an easy way to determine this, also known as the foil test.

This simple test involves taping strips of aluminum foil on the damp parts of your basement walls and leaving them on for 24 hours. A buildup of water drops (condensation) on the surface of the foil indicates a high degree of humidity inside your basement, whereas condensation on the other side of the foil is attributed to the dampness in the soil surrounding your basement walls. Meaning, the moisture in your basement has an outside source.

Humidity emerging from inside the basement can be countered in a number of ways, some of them mentioned in the list above. If the source of your problems lies outside your basement, however, you will have to waterproof the basement walls to prevent the moisture from wreaking any further havoc.

For this you may have to call on a professional waterproofing company, and this is likely to be expensive.

Waterproofing Your Basement

Assuming exterior waterproofing is not a problem in your case, it will involve professionals digging up the ground around your basement and removing the concrete within two-and-a-half feet of your basement walls. They will then excavate the dug-up area down to the footing to install new weeping tiles.

The exposed walls below the ground will be cleaned of debris and dirt. A coating of hydraulic cement will follow to fix the cracks in the area, followed by a double application of a rubberized asphalt membrane. The area will then be sealed and new weeping tiles installed along with a cloth filter to allow easy connection to the old weeping tiles. The dug up area will then be covered with gravel and completely backfilled.

The result? Your basement will now be properly waterproofed and will stay dry for years to come, no longer acting as a damper on your enjoyment of the rains.


Not every crack is a cause for concern, but you not noticing things till they lead to a full-fledged growth of mildew or a flooded basement, that definitely is a cause for concern.

All throughout this guide we have emphasized the need to be alert to the developments in your property that could point to a larger problem. If you do spot something out of the ordinary building on your walls or spot cracks where they shouldn’t be, look the problem up online to determine its probable causes. If you are not able to make a call on the matter, request a professional to come take a look.

Water, as we have seen repeatedly, can do a lot of damage and it is in your best interest to make your home resistant to it. A properly maintained and waterproofed house is not just safe to live in, it also fetches a higher market price. Educate yourself on the topic and implement the important measures to keep your property damage free.