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ToggleThe soil around your home that your foundations are sunk into is more than just dirt. It’s a vital component to your building’s structural integrity, offering support to the walls. That being said, soil also contains water and, thanks to the phenomenon of hydrostatic pressure, this can present some pretty serious problems.
Understanding Hydrostatic Pressure
Hydrostatic pressure is the pressure exerted by water on a submerged surface. As your basement walls are sunk into the soil and that soil contains water, they qualify for this definition pretty neatly. This groundwater pushes on your walls along with the dirt and under certain circumstances can even find its way through.
While concrete is pretty tough, it’s not impervious to damage. Water, under enough pressure, will find a way through. This could be through tiny, microscopic pores in the surface (which it will erode and widen) or, under enough force, by creating its own pathways in the form of cracks.
To give an illustration of how powerful the force of hydrostatic pressure can get: it can even push blocks out of the middle of your walls.
Factors that Influence Hydrostatic Pressure
All basement walls are generally acted upon by the water around them but, generally, they’re built to withstand the pressure. That being said, there are risk factors which can lead to increased risk of problems:
- Soil type and composition: soil which holds water rather than letting it drain naturally contains more. Loamy or clay-heavy soils are particular risk factors.
- Groundwater levels: the point where soil becomes saturated varies from place to place. Sometimes the water table is close to the surface, sometimes it’s much deeper. Heavy rains can even create a temporary false water table.
- Slope of the land: water flows downhill. If your home is at the bottom of a hill or a depression, water will gather there.
- Amount of rainfall: unsurprisingly, rain will increase the amount of water (and therefore the pressure) around your home.
- Proximity to water sources: lakes, rivers and streams all impact how much water will be in the soil around them. There’s a reason riverbanks tend to be slippery.
Signs of Hydrostatic Pressure in Your Basement
If you’re wondering if it’s worth calling up about a professional basement waterproofing assessment, there are signs to look out for.
Visual Water Infiltration
Water nearly always leaves a calling card when it gets where it shouldn’t. It can be as obvious as standing water on the floor or simply walls which are damp to the touch. Keep an eye out for signs like puddles, efflorescence (chalky residue on concrete walls) or staining on floors and drywall.
Musty Odors
‘Musty’ is a hard smell to put into words but, trust us, you’ll know it when it hits you. An earthy ‘basement smell’ is generally a sign that water is getting in somewhere. These humid conditions are perfect for molds and mildews to grow and that’s what produces the smell, even before you can see them.
You may also notice a humid dampness to the air when you venture down there.
Mold Growth
As we just pointed out, molds absolutely love damp conditions. If you’re noticing black or green spots appearing on your walls and floors or items you have stored in the basement, there’s water getting in to feed them.
Structural Issues
Hydrostatic pressure can be strong enough to break through concrete slabs, producing cracks. These are obviously a weak point when it comes to letting water in and will get worse over time. Even if it doesn’t actually break through, hydrostatic pressure can cause walls to bow (which can be even more serious than cracking).
Sump Pump Issues
If you’ve been proactive enough to have a sump pump system installed, and you notice it cycling more often than expected, that’s a warning sign. Not only does this mean that you’re dealing with a lot of water and the attendant pressure, it risks burning out your pump prematurely.
Mitigating the Impacts of Hydrostatic Pressure
While hydrostatic pressure will always be present, there are steps you can take to reduce its impacts.
Internal Drainage Systems
Installing a sump pump and interior French drains can help mitigate the risks associated with hydrostatic pressure.
Sump pumps sit just below the surface of your basement floor. When the pit they sit in fills with water, it activates a float switch, spinning the impellor. This creates an area of negative pressure, pulling the water away down a discharge line before it can threaten your floor. Combining it with an interior French drain means that it’s even more effective.
Exterior Drainage Systems
As the problem comes from outside the walls, it’s often best to plump for the exterior solution. These include things like:
- Exterior French Drains which channel water away from your walls
- Fixing grading and drainage by ensuring there is a slope leading away from your foundations
- Installing waterproof membranes to block water from making direct contact.
Foundation Repair
Hydrostatic pressure can cause cracks and bowing walls. Cracks and bowing walls will get worse over time as the pressure continues to push on them. Dealing with these problems quickly, reinforcing where necessary, will mitigate the impact of continuing pressure.
Choosing the Right Solution
When it comes to waterproofing, there’s no such thing as a one-size-fits-all solution. Every building is different and every location has its own set of issues to contend with. This means that if you’re thinking about dealing with problems long term, you really should consult with the professionals.
A reputable firm of basement waterproofers will be able to help you tailor your solutions to your particular problems. They’ll assess things carefully and present you with your options, weighing out the extent of the problem, your budget and longevity of the solution.
The Importance of Regular Maintenance
Of course, even the best hydrostatic pressure mitigation systems are only as good as their maintenance cycle. Once they’re installed, you need to make sure they’re kept in working order. Scheduling a regular inspection from the pros will alert you to any developing issues before they become an expensive problem. There are things you can do yourself though:
Inspecting, cleaning and testing a sump pump is pretty straightforward and will ensure that it’s ready for when you need it. Keep the sump clear of debris and periodically empty a bucket of water into it to make sure everything is running properly.
Many basement water problems originate on the roof. Keeping gutters and downspouts clear should be done at least twice a year to prevent water backups and spillage.
With such a potentially serious series of problems, investing in maintenance makes sense.