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Prevent Foundation Cracks: Water Your Basement

Updated on April 21, 2017
Slab, basement, and crawlspace foundations are at risk of damage in changing soil conditions, whether they're made from concrete, block, stone, or other materials.
Slab, basement, and crawlspace foundations are at risk of damage in changing soil conditions, whether they're made from concrete, block, stone, or other materials. | Source

About House Foundations

It doesn't matter if we're talking about businesses, relationships, or buildings, we all know the importance of a good foundation. nothing can last with a weak foundation. Of course, when quality deteriorates, so does value.

As a realtor, I help buyers navigate the trade-off between cost and quality in the homes they buy. I've found that a lot of things can spook buyers, but flooding basements, cracked foundations, and mold are probably the biggest three reasons a house that is otherwise attractive won't get offers.

Still, I didn't understand how quickly a change in soil moisture can cause expensive problems until a few years ago when a particularly dry spring in Kansas City caused our back patio to suddenly split in half. My husband had already fixed a leak from a crack in a basement wall before we met, but during our first year together, there was a drought here in the midwest, where we're known to have expansive clay soil. One day, we arrived home from work and discovered a half inch drop in just half of our patio! We were lucky it was just our patio slab and not the foundation itself, because this is a common occurrence in houses I sell, and it almost always costs several hundred dollars or more to fix, with the most expensive repair I've seen so far costing about $12,000! One crack had already happened. It could easily have been worse for us!

Once you've taken ownership of your very own castle, you'll want to ensure that it holds its value with minimum effort, so I encourage you to make sure those three deal-breakers never happen to your house! In this article, we'll look at some foundation problems and learn how one very simple, almost free step can prevent certain types of foundation failure.

Compare Foundation Settling to Foundation Shift

Although I'm not a home inspector or construction expert of any type, I've picked up a few things over the course of a few hundred home inspections and appraisals. Still, a standard disclaimer: You should always consult the appropriate experts if you are not sure about what you're doing!

Ok, good! Let's start with the difference between foundations that settle and those that shift:

Signs of Settling:

  • Hairline cracks at door or window corners.
  • Nail "pops" out of the drywall, taking a circle of paint with it.
  • Creaks, groans, clicks, and pops in the home, especially at the beginning or end of day.
  • Mild unevenness in main floor, such as bowing or warped floors.

Settling happens because the materials used to build a home— wood in particular, but also other materials including plumbing and ductwork— change depending on what's happening in the environment. Humidity can cause wood to swell, while dry conditions may lead the lumber to shrink instead. Metal ductwork can can "pop" inward or outward when temperatures shift a few degrees. Plumbing lines can expand and contract with temperature changes, too.

Signs of Shifting:

Most settlement is nothing to worry about, but shifting is something to worry about, and signs of a foundation can often resemble simple settling. For instance, with settlement, those diagonal cracks at the doors or windows won't affect the way they open and close. However, if foundation problems begin, those same cracks may get larger and cause windows to get stuck or to become difficult to open. Doors may not operate as smoothly.

Signs to Watch for:

  • Doors and windows that no longer operate smoothly.
  • Larger than hairline cracks at window and doorway corners.
  • Cracks in walls and sometimes floors that are larger than hairline cracks, particularly if the material on each side is moving away from the other side. Both sides moving in opposite directions are a big red flag! These cracks are especially noteworthy if they are horizontal, and not simply a straight line from tape hiding the seam between drywall panels.
  • Unexplained water in basement after confirming it's not from the HVAC, water heater, or other plumbing. (Often found near basement corners and windows.)
  • In slab foundations, water or insects getting in through the flooring or carpet.
  • More severe buckling or waviness in floors.
  • Bowed walls, particularly in basement.
  • Significant gaps where baseboard, crown moulding, or drywall has pulled away from a surface it should adhere to. (Also look for caulk lines, especially along interior and exterior fireplace surfaces.)
  • Horizontal cracks in concrete that may indicate shearing.
  • Missing mortar in brick facades or fireplaces and stair step crack patterns. (This isn't necessarily related to foundation shift, but can be a symptom.)

Erosion can undermine a foundation. This is common on hillsides, sandy soil, and areas with poor drainage control.
Erosion can undermine a foundation. This is common on hillsides, sandy soil, and areas with poor drainage control. | Source

Causes of Foundation Shift

Although I'm not a foundation expert, I have discovered a few main reasons that foundations can shift or fail. There may be others that I don't know about, but the ones I see most often result from poor planning, poor drainage, poor materials, or poor maintenance.

Poor planning is what happens when a home is built on land that is literally moving. This is not uncommon on hillsides, for instance. One of the most extreme examples I have personally seen was along Portuguese Bend near San Pedro, California. Houses were built along a fault line where earthquakes and plate tectonics cause the earth to move constantly. Several houses were dangerously at risk of collapsing. I had noticed that one desperate owner crammed pallets between the earth and the underside of the house in an attempt to prevent the foundation from shearing! Building on hillsides can create similar risks if a builder doesn't ensure proper drainage control and methods for controlling erosion, like planting landscaping that will anchor the soil and installing french drains.

Poor drainage isn't just a hillside problem, though. Rain gutters may carry water away from a roof and dump it at the corner of our home - creating the very problem the gutters are supposed to prevent! Low spots near the basement can hold water, allowing it to flow around our home's perimeter. In basement construction, the water can seep through concrete walls, cinder block, or mortar joints. With slab construction, water can flow below the slab, eroding earth or causing an expand/contract cycle in the soil during freezing weather. Either way, the end result can be a concrete slab that collapses or buckles.

Poor materials may have been fine when they were used, but might not be ideal now. In the midwest, many basements were created from limestone rocks, for example, and nearly all of them develop flooding in the basement years later.

Poor maintenance may be the result of inattentive, busy owners, but since it's the easiest one to prevent, you won't be *that* kind of owner, right? Right. Because once your drainage and materials are sound, you'll barely need to do a thing, but if you don't, it can cause very sudden, unexpected failure!

So, let's look at how to water a foundation.

Hurricane Katrina provided an extreme example of how too MUCH water can undermine a foundation. Do you think the owners shared the graffiti's artist's sense of humor about this?
Hurricane Katrina provided an extreme example of how too MUCH water can undermine a foundation. Do you think the owners shared the graffiti's artist's sense of humor about this? | Source

How to Water a House Foundation

You'll want to figure out if your foundation is needing water. If you see a gap between the dirt and the foundation, then your soil has pulled away from the house. By watering it, you'll allow it to expand again and provide more support for your foundation.

There are two excellent methods for ensuring that your foundation retains the support it needs around it: Irrigation and landscaping plants.

Landscaping Plants

Shrubs and grasses around your foundation help you keep your home looking nice and can add to your property's curb appeal. They also assist you in monitoring and protection the foundation if you are someone who notices when your plants droop or your grass is dry, yellow, or just plain dead.

If your foundation doesn't have any greenery around it, you can add some. This ground cover will keep the sun off the ground, which in turn, slows evaporation to keep moisture in the soil. Just keep your landscape watered as needed to keep your plants thriving. Add some mulch - around an inch or two deep - for extra protection.

In drought conditions, you may discover that you're not allowed to water outdoors or that you have strict limits about how you can use water outdoors. If that's happening in your area, keep reading. The irrigation method can be useful to you.

Irrigate Your Foundation

For homes where plant cover isn't used or where water restrictions impose challenges, the irrigation method may be better. Lay out a soaker hose about a foot from the foundation wall (give or take a few inches as needed!) Don't turn on the hose full blast! Instead, use lower pressure in the hose so that you don't create other problems by causing pressure to force its way back into your indoor plumbing.

Some experts say that a few short cycles per day is ideal, while others advise a longer soak 2-3 times a week. The goal is to simply maintain stability in the soil's moisture content, so what is "best" for your area will depend on the type of soil you have, recent rainfalls, and how much water may be getting removed from the ground by trees, shrubs, and grass. (Large trees can use an awful lot of ground water!)

My personal opinion is that a combination approach is a good idea. By maintaining some smaller shrubs and grasses with some mulch in the front and back yard areas, we notice changes sooner, which is important during seasons where we don't water (like winter here in Kansas!) But we do have a soaker hose like the one above that gets put to use regularly in the summer to keep them watered and ensure that we don't develop any more problems.

Best part - it's almost a set-it-and-forget-it maintenance upkeep, which is my favorite kind!

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