Wet basements are one of the most common house issues. While they have the potential to do some damage to a home, they can also really mess up a real estate transaction. The good news is that water intrusion doesn’t have to kill a deal. 

Before we discuss the best solutions, let’s look at the issue.

Why do basements get wet?

Water is the number one enemy of homes. Water intrusion can result from a leaking roof, a plumbing issue, or a grading problem. However, in most cases, water comes in through the foundation walls. Unlike a burst pipe, leakage through the foundation may be ongoing and intermittent. And it only happens when it rains, often concealed behind wall finishes, so it may not be noticed for some time.

Over 95 per cent of basements experience water intrusion at some point, but water penetration through a foundation rarely causes structural problems to the home. Most of the damage from water intrusion is to interior finishes, furniture and storage, which can be particularly expensive in finished basements.

Many homeowners don’t realize that a house is not a boat. If you surround it with water, water will get through. Building codes typically require damp proofing of foundations, not waterproofing. And the damp proofing does not last forever.

What are the signs?

There are many signs of basement moisture other than visible water on the floor, and it’s not always this obvious.

The signs include discoloration, rot or rusted nail heads on baseboards and panelling, water-stained or deteriorating drywall, water-damaged cardboard boxes on the basement floor, storage raised off the floor to protect it, efflorescence (white salt crystals) on concrete and block foundations or columns, rust at the base of steel columns and other metals near floor level, mould, musty odours, peeling paint, lifting floor tiles, a humidifier in the basement and a sump pump that runs most of the time.

There may also be signs of repairs, including patches or evidence of epoxy or polyurethane injections at cracks in foundation walls inside and the top of drainage membranes against the foundation at grade level outside.

That’s quite a list! When prospective homebuyers see any of these, it can scare them away. But in most cases, it shouldn’t. Before we get to the solution, a word of caution—sometimes there are no clues. Finished basements may have concealed problems. That’s why home inspectors use moisture meters and offer advanced thermal imaging inspections as a separate service.

What’s the solution?

In a nutshell, keep water away from the foundation. Yes, it really is that simple for most homes. Let’s look at the solutions starting with the most common one, which is also the easiest to implement.

Eavestroughs (gutters) and downspouts have an important function: to drain the water that lands on the roof well away from the home. When gutters are missing, clogged or ineffective, we get lots of water accumulating against the foundation, which finds its way into the basement because, as we know, a house is not a boat. Cleaning the gutters every spring and fall is an important part of regular home maintenance.

Downspouts are even more important: they collect all the water from the eavestroughs and carry it away from the home. They carry large volumes of water; if they are missing, damaged, clogged or too short, they put a lot of water in one spot against the foundation, resulting in leakage. The single most common problem is the downspout discharges water close to the foundation rather than six feet (two meters) away from the home. The photo below speaks for itself.

The following illustration shows how simple this issue is to correct.

Source: Alan Carson, Carson Dunlop Home Inspections

The $10 solution looks like this: a simple downspout extension. While there are a lot of variations, the idea is to extend the downspout so that water is directed away from the home.

I know, it sounds too simple to be true. I thought so too. But after 45 years in the home inspection industry, I’ve come to know it is a fact.

To summarize, eavestroughs and downspouts must collect roof water and carry it six feet (two meters) away from the home to keep the basement dry.

Source: Amazon.ca

One more thing…

The second most common cause of wet basements is equally simple but takes a bit more to address. The ground around the home should slope slightly down and away from the house, not towards it. Again, if all the rainwater on the ground drains toward the home, it will accumulate against the foundation and leak through.

The solution? Slope the ground away. It does have to be significant—a drop of six inches (15 cm) over 10 feet (three meters) works well. Driveways need even less slope; as long as water runs away from the home, that will work. It does not require a landscaping contractor to solve the problem. A shovel, some topsoil and a bit of muscle can change the slope.

Conclusion

There is always more to the story and exceptions to every rule, but now that you know this, you can easily identify and solve most wet basement issues. This is a terrific tool to help you provide great value, keep things in the proper perspective for clients, and avoid derailing a real estate transaction unnecessarily.

Alan Carson

Alan Carson is the founder and CEO of Carson Dunlop Home Inspection. Since 1978, Carson Dunlop has pioneered the profession and remain leaders today, as the oldest and largest home inspection company in Canada.