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  • Writer's pictureIryna B

Common Exterior Basement Waterproofing Problems and Solutions

Updated: Jul 19, 2023


If you’re like most homeowners, you spend the majority of your time in the upper levels of your home. Unless you’ve finished a section of the basement as an exercise room, office, game room or laundry, you only venture downstairs occasionally. When you do, you might brush off those basement odours or the damp, musty feeling on your skin as normal. What does a normal basement look, feel and smell like? I’m glad you asked.

It’s dry.

It’s that simple and that complicated. If your basement doesn’t look dry, feel dry and smell dry, you’ve got a problem. The severity of the problem will depend on a multitude of factors that can be accurately determined by the professional waterproofing company. A thorough evaluation and flood prevention plan established by one of their expert technicians can provide peace of mind and protection from water infiltration for years to come.

While there are preventative measures you can take inside and outside, I’ll focus on the exterior as troubles generally arise from overland flooding, rainwater, snow melt and the water table. The methods listed below require some expertise, can be extremely labor-intensive and sometimes, dangerous. Rely on an experienced waterproofing company to do the job right.

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The poured concrete or masonry block walls that make up the foundation of your home are quite porous, and if left unsealed can quickly allow water to permeate through to the interior of your basement.. Methods of waterproofing during construction have improved over the years; but if your home is more than ten years old, it’s possible the original water barrier has broken down and allowed deterioration. Cracks and other structural damage will eventually succumb to exposure from hydrostatic pressure, excess ground water, poor drainage and the rising water table and allow water infiltration. Each crack must be cleaned with a wire brush to remove any loose debris; then, epoxy is injected or granular clay is used to fill the area to form an impenetrable water barrier.


Once cracks and holes are repaired, it’s important to apply a sealant or waterproof membrane to the exterior foundation walls. This will further block water from entering your basement. There are two preferred types recommended for exterior use: Bituminous and Elastomeric waterproof membrane. Bituminous is the most common membrane. It’s petroleum based and comes in a liquid emulsion form. It’s extremely sticky, holds well to vertical concrete surfaces and can be applied with a trowel, roller or sprayer. A reinforcing fiberglass webbing is generally used between applications, and seams are covered with Bitumen sheets. Elastomeric waterproofing membrane is made from polyurethane and is considered to be a lifetime waterproofing solution. This synthetic product can be applied with a roller or paint brush to the positive-side (exterior) of the foundation walls. It is much more expensive that other options, but it’s extremely durable, requires no reinforcement and is impermeable to water, chemicals and gases.

Regardless of the type of membrane or sealant you use, it’s important to have the work done by an experienced contractor like Aquamaster Drain, Plumbing & Waterproofing, Inc. Most product manufacturers require special training or certification to validate their warranty and safeguard your investment properly. In addition, most exterior repairs require excavation work which can be difficult to do without the proper equipment and can be extremely dangerous.


Weeping tile is really the most important deterrent to preventing basement flooding. Water is a powerful force and no matter how many obstacles you put in its way, like concrete walls, membranes or sealants, it’s going to find a way to go where it wants to go. However, all is not lost. Experience tells us that if you find a way to re-direct the water away from your home, you’ll have a higher chance of keeping your basement dry. That’s where weeping tile comes in.

Just like a garden hose directs water from the faucet to a sprinkler several feet away when you water your lawn, weeping tile or a French drain system will direct surface water safely away from your foundation walls. I’ll provide a somewhat detailed synopsis of how this works, but a visit to our help resources will tell you everything you need to know about weeping tile.

Terracotta tiles were once used for drain pipes, and even though today’s pipes are made from PVC plastic, the name still remains. Weep holes in the 4-inch pipes installed around the perimeter of your home allow water to drain away from the walls. With the holes facing up, plastic pipes are placed into a trench around the outside of the home or inside under the basement floor. Groundwater rises from rain or snowmelt and flows into the holes in the pipe. It then follows the slope away from the house or to a sump pump to be pumped away.

It’s possible your home may already have a system in place. If this is the case and you’ve encountered water problems, it may be plugged. Some common causes are tree roots or soil. If the water doesn’t drain away as fast as it enters the pipe, it can back up and press again the foundation resulting in basement cracks and leaks. There are several methods used for clearing a blockage. An initial drain camera inspection can determine the exact cause of the problem. A camera-tipped cable will be fed through the maze of drain pipes to find tree roots, corroded or cracked pipes, bursts or collapses or pinhole leaks. In blockage cases, a simple, trenchless cleaning using a drain snake or high-pressure water jetting or may rectify the problem. More serious breaks or leaks will require significant repair work.

If your home doesn’t have a weeping tile system currently installed, it’s likely going to be needed. Engaging a professional to do this back-breaking work is definitely recommended. They will have the proper equipment, can determine the proper slope needed and provide a warranty for any future issues. Your contractor will first need to excavate a trench around the outside perimeter of your home. It will slope one inch for every eight feet from the concrete footings. Two or three inches of washed gravel will line the bottom of the trench to filter the water without clogging. Landscape fabric is then laid on top of the stone or wrapped around a rigid PVC pipe. The layering continues with the pipe, a sand and gravel combination, then dirt and sod. A clean-out joint is often left above ground to help in future maintenance. The entire weeping tile system will channel water safely away from your foundation.


Looking up is as important as looking down when it comes to basement waterproofing. The roof of your home sheds a significant amount of water during rainstorms and when snow melts. All that water will fall straight down and lay along your foundation if there are no gutters or downspouts to direct it away. Water should be fed to an external drainage system away from the house. Regular checks for debris, blockage and damage are also important to maintain proper water flow. If your home is surrounded by trees, gutter covers may be the answer to clogging due to falling leaves and branches.


If your basement windows are located below grade, they may be letting in more than just light. A window well is a barrier system typically shaped in a semi-circle and made from galvanized steel, masonry or polycarbonate. An area outside the window is excavated, the well is affixed to the foundation and gravel is used to filter water to the weeping system and away from the home. Regular maintenance to keep drains clear of leaves and debris will stop water from overflowing. Clear covers are also available to keep the window well clean while still allowing light through.


When your home was built, the soil used to backfill the excavation area should have been sloped away from the foundation. After years of ground settling, seasonal precipitation, deck and patio installation, or flowerbed creation, the slope may have been altered and no longer directing runoff properly. A minimum slope of one foot for every 50 feet will keep excess water from accumulating along the foundation. Your contractor will know how to determine this 2-percent grade to reduce water seepage issues.

These exterior waterproofing methods should be used as a guide on how to prevent flooding. While exterior remediation work can be fairly labor intensive and expensive, it will definitely provide significant benefits. The only exterior preparation you must do is to move landscaping from the work area. The basement interior will not be disturbed and your possessions will remain in place. Large cracks and holes will be permanently repaired and with sealing, membrane installation and weeping tile in place, your home will be more structurally sound and protected from water infiltration. Simple do-it-yourself jobs such as keeping up with proper gutter, downspout and window well maintenance will also provide save money and prevent flood damage in the future. Remember, once the work is completed, you’ll need to watch for any new settling or grade adjustments after home improvement projects. Taking a proactive approach to basement waterproofing will reap the rewards of a normal, dry basement.

The experts at Aquamaster Basement Waterproofing are dedicated to providing high-quality, external waterproofing services and exceeding your expectations. Protect your investment by visiting our and requesting a free, on-site evaluation today.

About Aquamaster Basement Waterproofing

Aquamaster Basement Waterproofing is your full-service plumbing and basement waterproofing company assisting the Greater Toronto Area residents. We offer services such as drain repair, drain cleaning, basement waterproofing, basement underpinning, sump pump installation, and more.

Posted by Aquamaster Basement Waterproofing.

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