Wet Basement? An Ounce of Prevention Is Worth A Pound of Cure

Posted: May 12, 2017
By: Ryan Bowering

Wet Basement?

An Ounce of Prevention Is Worth A Pound of Cure            

"April showers bring May flowers" but flowers might not be the only things brought on by spring rains. At this time of year, people are most worried about cracks in the foundation, and the flooding that can ensue after a downpour. And well they should be! A wet basement is likely the number one concern I hear about during home inspections, and it can be an insurance issue as well. Buyers are being asked more and more to provide assurance that the house they are looking at for purchase has no indications of water/moisture issues in the basement or crawlspace, before being offered insurance coverage. And with the extremely wet weather we’ve had, it’s the perfect opportunity for leaking foundations to make a dramatic appearance. Several of the homes that I inspected last week had varying amounts of water on the basement floors and walls.

Every house, unless it’s brand new (and even then…) can have cracks in the foundation and/or walls. In fact, I would say that ninety-five percent of the houses I’ve inspected have cracks. They can vary in size and location and run every which way – horizontally, vertically, diagonally, stair step patterned, V-shaped, etc. – caused by a multitude of conditions or circumstances. If your basement is not finished, then you’re probably not all that worried by a bit of water – but if it is, it can be expensive, labour-intensive, disheartening, and messy to clean up after a flood. Do not store anything of great monetary or sentimental value in a known-to-be-wet basement.


Cracks: Small, Medium, or Large?

There’s a lot to take into consideration when determining the importance or liability of a crack. Anything under 2 mm is generally considered to be minor or typical. In this case, the more important issue is not the crack itself, but the conditions surrounding it. It really depends on the location (weak/vulnerable spot under a window?), foundation material (poured concrete, block, brick, stone), grading of the property near the crack (is it a low spot or sloping toward the foundation?), type of soil (clay, sand, etc.), whether the gutters and downspouts are clogged and/or dumping water directly beside the foundation, and whether the window wells are uncovered. Most of these are things that can easily and inexpensively be changed or added to remedy the situation, and if maintained properly, will reduce the risk of future leakage significantly.

Minor cracks can be sealed on the exterior and/or interior with foundation coating or sealant. Monitor the cracks over time to ensure they don’t enlarge. Walk around the home once a year or so to see/measure any increase in size. This is where a camera can come in handy – now you have something to compare the year’s or decade’s progression of the crack, if any. If a crack appears to be widening, or is causing larger step cracks through the brick walls above, it’s time to investigate further.

If you have a foundation crack that is 4 mm in width or more, this is where you start to become more concerned. Has it considerably affected the brick above the crack? These larger openings can bring more significant and expensive changes that need to be made for correction. Having a professional inject epoxy into the crack to seal it can be very effective, depending on the size and nature of the crack.

Severely cracked walls need more drastic measures to ensure your basement or crawlspace remains dry. Dimpled waterproofing membrane may be your only option to provide a barrier that will direct water down below the foundation to the footing tile to direct water away. It provides a long-term protective layer, applied to the exterior or interior of the foundation. When placed on the interior, it may be necessary to trench out the existing floor around the perimeter, directing the water down the wall to the footing tile. If no footing tile is present, you can lay tile in this trench before installing the foundation membrane.


Maintaining Proper Drainage & Ventilation

Clean the gutters a couple of times a year, repair damaged downspouts and ensure they’re not blocked with debris, add downspout extensions to 6 feet minimum from the foundation, cover window wells to keep them from filling up with water, and patch any open holes in the foundation and areas where mortar is missing. These improvements will greatly decrease the chance of moisture penetration, and are beneficial even if there are no cracks in your foundation!

Large trees and shrubs that are planted too close to the house are another potential cause of major foundation damage, and the roots can also fill sump pits and clog sewage drains and weeping tile. This is so easily preventable. Think about the future, mature size of the tree when planting. This simple, thoughtful decision can save major headaches down the road – including the cost of removal of the now enormous tree, repair of the foundation, and hiring someone to clean the roots out of the drains or replace pipes.

Ensuring the grading (including walkways and patios) is sloping away from the house is especially important. You really can’t talk about foundation cracks without talking about proper drainage! Water will always travel to the lowest spot, following the path of least resistance. Deep snow can also be an issue as it begins to melt. If the slope is toward the foundation, that’s the way the surface water will travel. And now, homes are being constructed in closer and closer proximity, creating a unique set of challenges to overcome regarding drainage. The solution is often to create a swale around the home – a graded slope and trough system that directs water away from the house into a storm drain or low area, providing a direct path.

Keep in mind that basement walls and especially floors are always vulnerable to moisture. To reduce moisture, operate a dehumidifier in the basement to about fifty percent humidity level. If you have a crawlspace, ensure there is proper drainage, ventilation, and a vapour barrier (6 mil poly) laid on earthen floors to keep the moisture down. Crawlspace ventilation is the biggest problem I see when investigating crawlspaces. Moisture can build up over time and do major structural damage. A few years ago, I inspected a home during the winter months, and as I opened the hatch to enter the crawlspace, steam billowed out. Never a good sign! There was no ventilation whatsoever. The foundation had been completely sealed by sprayfoam, and fungus and mould were growing everywhere! Parts of the columns and beams were rotting, settling, and failing. The buyer did not buy, and I was left with the heart-sickening task of explaining to an elderly woman that the house needed significant and costly repairs, before she would be able to sell. Once she and her Realtor were informed of this condition, it would have to be disclosed to all potential buyers. I’ve been in over a hundred crawlspaces, and this was one of the very worst!

Sprayfoam wasn’t the issue here – adequate ventilation was. If there’s nowhere for the moisture to go, it just builds over time – in effect creating a sauna! If there is a basement, as well as a crawlspace, I recommend venting into the basement. If there’s no basement, installing several louvered or screened vents around the exterior will do the trick. These should be left open most of the time, and only closed during very cold weather. Venting your crawlspace will go a long way in keeping it dry, or at least, drier. Sprayfoam is best for insulating basements and crawlspaces, as it repels moisture. It’s more expensive, but can be worth the extra cost because of the waterproofing capability.

Always test your sump pump before the spring and summer rains to make sure it’s in good working condition, and install a backup. If you have municipal/town water, I recommend installing a water-pressure backup pump. It will jump into action if the main pump fails, and will operate even during a hydro outage. Here’s a video I’ve posted before on my Facebook page that explains how they operate and how to install one – definitely worth a look!


This is not meant to be an exhaustive description of foundation repair – or even identifying the long list of reasons behind foundation cracks – and there are many! I am not a structural engineer – nor do I profess to be an expert on this topic. I am a home inspector. This is just a short, simplified explanation of basic foundation cracks. So, if you’re the kind of person who likes a lot of detail, and especially if you’re a diehard DIYer, check out InspectAPedia’s  Foundation Crack Dictionary. It has everything you ever wanted to know about foundation cracks and more.



Know your Limits

But if you’re not at all handy, and you have no idea what you’re doing, get help in identifying your particular issue and remedy. Call an expert! Family and friends are great resources for locating reputable contractors of any kind – and in the long run, it may actually be cheaper to hire someone, than attempting to save money by doing it yourself! There are many, many companies out there that specialize in waterproofing and repairing foundations and other structural components in basements and crawlspaces. Do your homework before hiring someone. Most of these companies will attend your property to provide a free estimate. Search online, get several opinions, ask for references – then go with the company that you feel has your best interest at heart, and has plenty of experience and knowledge about their craft – and isn’t so costly that you will have to put your firstborn up for collateral! Most foundation repair companies offer varying multi-year leakage warranties for epoxy injection, wrapping, or applying membranes to foundations – and their websites give a good indication of the type of work they do and materials used.

That’s it for now! Warmer weather is here and it’s a good time to get outside and investigate around the house. It's very important to examine every area, as the foundation is just one aspect to consider when it comes to home maintenance. And remember, an ounce of prevention can go a long way when it comes to creating and keeping a dry basement!

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