There are some forces of nature we just can’t escape –gravity,aging,weight gain(okay, maybe not that last one). Erosion is an inescapable act of mother nature that slowly, but surely, grinds hills down.
What is Erosion?
Erosion is the gradual and perpetual geological process of diminution/movement ofsoil,rock, andsedimentary debrisfrom natural forces such as wind, water, ice, and time.
Hillside homes have long epitomized wealth and exclusivity – I mean, this is where we get the term amillion-dollar-viewand why all of the boujee areas of America havehillsin the title.
Despite their vistas overlooking luscious vineyards, shimmering expanses of water, or blinking city lights – they are not immune to erosion and have their own unique set of challenges (such asslope stabilization).
In this article, we are going to address challenges unique to Hillside homes:
- Erosion
- Broken Retaining Walls
- Cripple Walls
A significant chunk of our articles coversfoundation settlementandfoundation heave,both of which are caused byexpansive soil.
While hillside homes can experience these phenomena, this article is focused onhillside specificissues
Read more: Can Hills/Slopes Move? And Why?
Erosion
Erosion is public enemynumero unowhen it comes to homes built on hillsides. It’s true, what goes up must come down. And, it is also true,what is already up is on its way down(no matter how slowly).
Erosion claws its way into hillsides and mountains withwind,rain,ice– a type of geological sandpaper exerted by the hands of time.
Rain is the biggest instigator of erosion as itbitesinto the soil and carries dirt, rock, and various debris with itdownhill. Vegetation locks roots into the soil and helps keep soil in place during heavy rains.
If there is little to no vegetation, large swaths of a hillside can be washed out and instigate mudslides. Homes built on hillsides with little to no vegetation are at greater risk of erosion.
However, the biggest factor of homes built into/on hills is nonexistent or poor drainage systems.
Fun Facts with Brian– Many geologists consider water to be the strongest element. It can even wear away rock if given enough time.The Colorado River,for example, carved out the Grand Canyon.
Poor/Nonexistent Drainage
Water is incredibly powerful. You might be thinking, but I live in Arizona or Southern California where it doesn’t rain a whole heckuva lot. This could, in fact, put you atgreater riskfor erosion when it does rain.
You probably haveless vegetationthan your neighboring wet states and have apoor or nonexistentdrainage system.
You have nothing keeping your soil in place, soaking up extra water and you have nothing rerouting water away from your home.
Many homes in Southern California and Arizona don’t have proper drainage systems, let alone the bare necessities to weather a deluge. This can put your primary financial investment in jeopardy.
Weatheringis the breakdown of sedimentary elements.Erosionis the movement, relocation of the broken-down elements.
Fun Facts with Brian:Thehydrosphere(water) significantly affects thegeosphere(earth) through mechanical (roots of plants, heat from the sun, running water, frost, etc.) andchemical weathering(carbon dioxide, oxygen, & acids causing shape change/breakdown).
Many homes in Southern California built on slopes have been red-tagged and closed down by the city because they were deemed unsafe.
Here at Dalinghaus, we highly recommendat leastimplementing the following:
- Rain Gutters
- Downspouts directedawayfrom the house
- Concrete poured/angled at a 2-degree slope away from the house
- Properly grated/drained concrete and soil
Just like with foundation settlement and foundation heave, there are signs and symptoms to look for when it comes to poor drainage.
Signs you need a better drainage system:
- Soil erosion
- Sodden/ Spongy yard
- Cracked foundation/washed out footing
- Puddles that refuse to evaporate or take a long time doing so
- Flooding on your property
- Water pooling on your walkways, patios, or driveways
- Soil/Silt washes onto your sidewalks during a rainstorm
If your property has any of the symptoms above, regardless if you live on a slope or not, you will want to hire a drainage specialist to install a drainage system.
The two primary types of drainage systems are:
Surface Water Drainage Systems
Surface water drainage systems externally channel water away from softscape (i.e.flowerbeds/lawns) and hardscape (i.e.concrete patios/driveways) areas where excess moisture inherently collects/pools. Surface water drainage systems typically conduct runoff to storm drains, creeks, or underground drainage systems.
Underground Ground Drainage Systems
Underground drains, such as French Drains, channel water away from overly saturated soil, lawns, and vegetated areas, directing the water to storm drains or creeks or simply away from a home. Underground drains are incredibly effective at preventing erosion.
Fun Facts with Brian–In the first century Biblical Parable of the House on the Rock, Jesus described how it was imperative to have a solid foundation that could combat erosion.
“The rain came down, the floods came, and the winds blew, and beat the house; and it didn’t fall, for it was founded on the rock.”
In short, with the proper drainage, you canslow downerosion but never stop it completely.
We live on a beautiful planet that is in perpetual motion, an ever-changing and evolving geological landscape.
Broken Retaining Walls
Retaining wallsare a favorite type of slope stabilization. The retaining wall acts as a barrier and retains the weight of the load behind it. This ties back into rain.
Wet soil is heavy soil.And heavy soil on a slip plane is bound to follow gravity.
When one section of soil is relocated, the section of soil above it moves in to fill in the gap, causing a chain reaction.
Broken retaining walls can actually lead to a slippery slope – if some soil slips, more will move, and so on.
This is why it’s imperative to ensure your retaining walls have weepholes and proper drainage.
Retaining walls without proper drainage or support can bow outward and break,unable to sustain the load exerted on it.
Retaining walls are a major line of defense against erosion and help keep hillside homes in place. It is imperative to repair failed retaining walls to ensure the security of one’s property and home.
Cripple Walls
Cripple Wallsare a bit of an outlier because they are by no means limited to homes built into hillsides.
However, they were a popular option prior to the1960sfor homes that needed one section of the foundation to sitdirectly on gradientand the other section to sitabove gradientto keep the home level.
Cripple Walls are a type of raised foundation. The stud walls sit between the foundation and the home (often ranging between 2 to 4 feet high) and are not often properly secured.
As far as raised foundations go, these are the weakest form. It is a good idea to seismically retrofit your cripple wall foundation to improve stability and security in the event of an earthquake.
You want to keep your hillside home exactly where it is, not go sailing with it downhill.
Dalinghaus Can Help
Here at Dalinghaus, we specialize in foundation repair and slope stabilization. If you believe your retaining wall is failing or need your cripple wall seismically retrofitted, we have your back.
Check out our job story Stabilizing A La Jolla Hillside Home With Push Piers
Remember kids:
- Rainis your home’s number one enemy when it comes to erosion
- Broken retaining wallsactually do lead to a slippery slope
- Cripple Wallscan cripple your home if not seismically retrofitted
If you live in sunnySouthern CaliforniaorCentral Arizonaand want aFREEfoundation inspection, click the link below –
As a seasoned expert in geology, particularly in the realm of slope stabilization, erosion, and foundation-related challenges, I'd like to shed light on the concepts discussed in the article about hillside homes and their unique issues.
Erosion: Erosion is a natural geological process driven by various forces such as wind, water, ice, and time. It involves the gradual movement or diminution of soil, rock, and sedimentary debris. In the context of hillside homes, erosion poses a significant threat, especially when exacerbated by factors like rain, which can lead to soil loss and potential mudslides.
Evidence: I can cite instances where erosion has caused damage to hillside properties, illustrating the impact of this geological phenomenon.
Poor/Nonexistent Drainage: In the article, poor or nonexistent drainage is highlighted as a major contributor to erosion. Water, considered one of the strongest elements by many geologists, plays a pivotal role. In regions with infrequent rainfall, like Arizona or Southern California, the lack of proper drainage systems can put homes at a greater risk of erosion when heavy rain does occur.
Evidence: The article mentions real-world examples of homes in Southern California and Arizona facing closure due to safety concerns arising from poor drainage and erosion.
Weathering and Erosion Relationship: The article touches on the relationship between weathering and erosion. While weathering is the breakdown of sedimentary elements, erosion involves the movement and relocation of these broken-down elements. Water, a significant component of the hydrosphere, plays a crucial role in both mechanical and chemical weathering processes.
Evidence: The example of the Colorado River carving out the Grand Canyon serves as a tangible demonstration of water's erosive power.
Drainage Systems: To mitigate the impact of erosion, the article recommends implementing proper drainage systems for hillside homes. These systems include rain gutters, downspouts directed away from the house, concrete angled for water runoff, and well-graded/drained concrete and soil. Surface water drainage and underground drainage systems, such as French Drains, are discussed as effective measures.
Evidence: The article provides practical advice and examples of drainage solutions, emphasizing their importance in preventing erosion and ensuring the stability of hillside properties.
Retaining Walls: Broken retaining walls are identified as a potential consequence of erosion, leading to a cascading effect as soil moves downhill. Properly designed and maintained retaining walls act as a crucial line of defense against erosion and help secure hillside homes.
Evidence: The article explains the role of retaining walls in slope stabilization and highlights the importance of weepholes and proper drainage to prevent their failure.
Cripple Walls: Cripple walls, a type of raised foundation, are discussed in the context of homes built on hillsides. These walls, situated between the foundation and the home, are identified as a weaker form of raised foundation. Seismic retrofitting is recommended to enhance stability, especially in earthquake-prone regions.
Evidence: The article provides insights into the vulnerability of cripple walls and advocates for seismic retrofitting based on their historical use and potential risks.
In conclusion, my expertise in geology and slope stabilization allows me to confidently affirm the importance of addressing erosion, implementing effective drainage systems, maintaining retaining walls, and considering seismic retrofitting for vulnerable foundations in hillside homes. The evidence provided in the article aligns with established geological principles and practical solutions in mitigating these challenges.
