Home Improvement

Warning Signs Your Basement Waterproofing Needs Repair


Water is tricky stuff. It’s got a habit of getting where it shouldn’t and, given that it can do damage ranging from unpleasant smells to structural collapse, its worth keeping an eye out for those more subtle signs before things get out of hand.

Common causes of waterproofing failure

There’s an almost endless list of things which can cause waterproofing to lose effectiveness but the most common problems are:

  • Poor initial installation
  • Soil settlement
  • Aging infrastructure
  • Unexpectedly heavy rains and flooding

Signs of Water Damage To Be On The Look Out For

Not all signs of water damage will result in puddles. We’ll break the various symptoms down into four categories:

Visible Signs Of Water Damage

There are a few obvious signs that water is finding its way past your waterproofing and into your basement. Be on the lookout for:

Dampness and Water stains

The most obvious sign of water damage is that things are damp. If you notice a spreading wet patch on your basement floor or walls, that water must be getting in from somewhere and you’ll need to investigate.

Peeling Paint

If you find your paint or wallpaper peeling or flaking off, the most likely culprit is water pressure is forcing it away from the walls. When water gets in behind the coverings, it pushes against them until they come away from the surface.


This takes the form of a white, chalky residue on your basement walls. It’s caused by water pushing its way through the concrete of your foundations and dragging minerals with it. When the water evaporates off the surface, efflorescence is what’s left behind.

Mold and Mildew

Molds and mildew thrive in damp environments. If you notice black spots and musty odors coming from the things you’re storing in your basement, the chances are that they’ve gotten damp.

Musty Odors

Often going hand-in-hand with mold and mildew growth, musty odors are often an early warning sign that water is collecting in your basement somewhere and will require investigation before things get worse.

Structural Indicators of Waterproofing Problems

Sometimes water intrusion can leave behind evidence in the very structure of your foundations. If you spot any of the following, it’s worth investigating further.


Perhaps the most obvious structural sign of a problem with your waterproofing systems is the formation of cracks in the walls and floor of your basement. There are a few different forms that these can take and some are a normal part of a new-build home settling, but they need keeping an eye on.

Bowing or Leaning Walls

The walls of your basement are under constant pressure from the earth around them. Sometimes, when groundwater levels rise after heavy rain, this pressure can be strong enough to physically move the blocks of your wall. If you notice this happening, you should contact a structural engineer.


While not strictly structural, noticing rust on your appliances or any metal fittings (or even metal objects you’re storing) in the basement strongly suggests that water is finding its way in somewhere nearby. Rust is caused by the oxidisation of iron and it almost always requires water to form.

Signs of Moisture And Humidity Issues

Not all waterproofing deals with stopping water getting in. We also have to worry about allowing water out again.

Signs that your home may have issues with humidity include:


Finding your walls are wet to the touch or your windows are constantly misting up means that the humid air in your basement is causing condensation as it touches the cold surfaces. This provides the perfect habitat for molds and mildews.

Elevated Humidity

If you open the door to your basement and suddenly feel the air is thicker, that’s a good sign that you’re facing a humidity problem. All air contains a certain amount of water vapor but when the level gets too high or it collects in one area, it can lead to all kinds of problems.

Warping Wood

Wood absorbs water from the air around it and sometimes this can be enough to force it out of shape. If you notice doors sticking when they didn’t before or shelves bowing without much weight on them, it’s a good indicator of moisture problems nearby.

Deterioration of Drywall and Insulation

Drywall is particularly susceptible to damage from moisture and will quickly start to crumble if it gets wet. Other signs to watch out for include bowing or leaning, both suggesting that the drywall is starting to fail.

Many types of insulation also require dry conditions and will act like a sponge, holding moisture in and causing mold growth.

Exterior Warning Signs

Keeping an eye on the exterior can let you get ahead of problems before they become evident on the interior.

Pooling Water

Finding water lying around the outside of your basement wall suggests that you might be facing drainage issues. Without an easier path to drain away, this water could well find its way inside your home.


As we mentioned above, not every crack in the wall is an omen of doom, but they’re always worth investigating. A crack provides a very easy path for water to get through your waterproofing measures.

Guttering Issues

While it may seems strange to look up for the source of water getting into your basement, guttering provides the first line of defence for your whole home.

Importance of Waterproofing Repairs

It goes without saying that if you spot any of the signs above, you’re going to need to get the issue fixed. Left unattended, water ingress can cause problems ranging from mold growth to structural collapse and, at the very least, damage to your home’s value.

Steps to take

If you notice something that suggests water is getting through your waterproofing, the first thing to do is organise a proper inspection. A professional waterproofing contractor will be able to advise on any necessary repairs or upgrades based on your particular situation.

Depending on what exactly they suggest, it might be possible to undertake the work yourself. However, there are certain jobs which are best left to the pros and, even with the smaller tasks, the peace of mind knowing an expert has worked their magic can be worth more than you save with a DIY job.