Although you may never see it, the foundation of a home is a vital aspect to its strength and stability. A proper foundation does more than keep your house above ground: It should also keep out moisture, insulate against the cold and resist movement of the ground surrounding it. There are many factors to consider, such as drainage around your house and soil condition, to help avoid a cracked foundation
. The type of soil can have a big impact on the quality and lifespan of your home’s foundation.
Types of Soil
Soil shifts and moves over time often as a result of how it handles moisture and the climate — including the freeze / thaw cycle. As soil shifts, it changes the support around your foundation, which can lead to cracks. And it’s those cracks that can allow in moisture and maybe even some pests.
Each type of soil is comprised of different properties that have various effects on the bedrock of a home. Soil with good structure is going to be more stable. The way in which soil handles wetting and drying cycles is also an important consideration, as expanding soil can put unwanted pressure on foundations and soil that retains too much moisture can cause the foundation to weaken.
Here are the most common types of soil and how they measure up:
Peat: Usually dark in color, peat is easily compactable because it holds a great deal of water, which makes it prone to shifting. This is not ideal soil for a foundation.
Clay: Because it’s made up of tiny particles, clay shrinks significantly when dry and expands when it’s moist. The extreme changes can put pressure on the foundation, which opens the door to potential cracks.
Silt: Usually smooth to the touch, this type of soil tends to retain water longer and drains poorly. This can push against and weaken foundations when wet.
Sand / Gravel: A better choice than peat, clay or silt, sand / gravel drains easily and does not retain moisture because it’s made up of larger particles. However, when wet, these particles can be washed away leaving gaps around the foundation.
Loam: Typically, a combination of sand, silt and clay, loam is an ideal soil type for supporting foundations, as it is able to maintain water at a balanced rate.
Rock: The strength and stability of rock makes it a great choice for foundations. However, it can be difficult to dig into, and homeowners should be sure the rock is level before constructing the foundation.
Effects of Drainage Around Your House on Your Foundation
So, what exactly happens when you have poor drainage around the house? More than you might think! Keeping your foundation safe is paramount to protecting your home and everyone in it. Here are some of the effects that constant, unmanaged drainage can have on your property:
Moving water affects anything it touches, which includes the soil around your home. The more drainage there is, the more erosion that will happen. Over time, that erosion will cause a significant amount of soil to be displaced.
Because your foundation was built with that soil around the home, any loss can cause shifting and reduce its overall support from the environment around it. The longer this erosion goes, the weaker your foundation becomes due to cracks and further shifting.
In addition to being displaced, soil also absorbs moisture. Depending on the type of soil around your home, its level of expansiveness can vary. The more expansive it is, the more risk your home is at when drainage is left uncontrolled.
Certain soils can absorb a great deal of moisture, expanding significantly. This puts pressure on your foundation and can quickly lead to cracks and shifting.
Soil expansion is a threat that can’t be completely eliminated. However, reducing drainage to the soil goes a long way to mitigating how much expanding it can do. Waterproofing around your foundation can often be the only way to prevent problems if you have soil with high potential for expansion.
We like to think of concrete as sturdy and reliable. While that is true, the properties of concrete aren’t exactly what you may expect. Primarily – did you know it’s porous? All those holes in concrete are susceptible to incoming moisture – and it’s common for most homes to experience absorption.
In small amounts, this absorption isn’t a major problem. The moisture enters in small amounts and can evaporate. But in home foundations with poor drainage issues, the constant assault of moisture means the concrete keeps absorbing more and more.
Over time, this water breaks down the concrete and leads to cracks. Those cracks weaken the foundation, and continue to grow unless dealt with. One ignored crack in your foundation is all it takes to lead to leaks and eventually major damage!
Improving Drainage Around Your House
Whether your home is resting on stable or not-so-stable soil, water drainage is an important part of maintaining the life of a foundation. Poor drainage can cause problems like water in the basement or structural damage, while proper surface drainage can lead moisture away from your home ultimately protecting the precious foundation. Here are some things you can do to ensure better drainage.
Roof gutters and downspouts: Gutters should be kept free of debris and direct water to downspouts that carry it away from the foundation. Be sure they’re draining at least six feet away from the home — downspout extensions can help!
Sufficient grading: Check to see if dirt is graded away from the home. Housing codes have various requirements, but it’s helpful if the ground slopes away from the foundation for a distance of eight feet or more.
Basement windows: Sometimes debris and water can collect near basement windows, so be sure to provide adequate drainage to the foundation drain.
Sump pumps remove excess water from around your basement and are best for minor amounts of groundwater. Ensure your sump pump is in good, working condition and consider a battery back-up.
Install foundation drains: This repair consists of removing portions of existing basement slab, installing new drains directing water to a sump pump and then installing new slab. Learn more about
basement waterproofing options