I strongly recommend GEO inspections for all Hillside properties. A house is only as good as the foundation it is built on, and a foundation is only as good as the ground it rests on top of. Hillsides that have had mudslides before, or the soil is loose fill, or the foundation of the house is undergoing creep- these are financial disasters! To make matters worse, an undiscovered geological issue could make the property you buy unmarketable! Geo Inspections cost ~$1,000
GEO inspectors will walk the exterior of the property and hillside, check retaining walls, outdoor hardscape- such as pool and driveways, crawl underneath the house to check the foundation, and look inside the house for settlement cracks. It is important to note that a GEO inspection does not involve subsurface exploration. If a GEO inspection finds an issue that warrants further investigation- the Geologist may recommend in his report to have a hole dug to the bedrock to examine soil conditions. Excavation costs $2,500-$3,000. Soil samples from the excavation are sent to a laboratory for testing.
To prepare the report a Geologist will research:
- The City Building Department records
- Physical observation of geologic conditions at the site
Research of Records – Valuable information can be found in public records. The public records will have on file construction permits, city letters regarding past slope failures or mudflows, Inspector “Orders to Comply” to correct a condition at the site, letters regarding past earthquake damage at the site, prior soils or geology reports prepared for the site, and legal documents warning future property owners of certain site conditions or placing restrictions on use of the property.
Site Visit – Site conditions are evaluated from a visual perspective and no destructive testing is performed. Observation must be conducted both inside and out. An interior inspection is important because when settlement or expansive soils occurs there are obvious visual signs of distress. Door jambs don’t lie. If the door Jamb is cracked or crooked, or the door has been cut on the bottom so that it can properly open and close these are indications of settlement.
A good test is to set a golf ball on the floor, if there is enough slant to overcome the ball’s inertia and it starts rolling the floors are uneven from settlement. Finally, look at the ceilings for cracks. Some amount of settlement is expected, however large amounts of settlement can cause big problems, because there is no easy way to repair foundations. Foundation work tends to be very costly.
The GEO report covers a few different topics that are interrelated to the overall stability of the site. These categories are:
Rainwater needs to channel away from the house and into street gutters and the storm drain system. Some puddling is expected around the property. In area’s that are especially wet, like around the perimeter of the pool, special drain and sump pump systems can be installed to keep these areas from flooding.
Have you ever noticed Driveways are not flat? Drive ways have a slight grade toward the street. If the driveway has a negative grade, this will lead to water flow in the garage or underneath the foundation. Water can cause wood rot and create favorable conditions for mold and subterranean termites. Crawlspaces should be dry and free of debris, although if they are damp in some areas that is fine. If the crawlspace is muddy or has pools of water, there is either a grading problem or a plumbing leak which s
hould be fixed immediately.
Tashman Hardware on Santa Monica Blvd has a downward sloping lot. During a recent rain storm, employees put these sandbags out to dam the rainwater running into the store from the parking lot. What they really need to fix the problem is a drainage system.
The picture above was taken at a house in Holmby Hills on Charing Cross. Notice how the rain gutter has a drop that runs down the side of the house and underground, to an opening on the curb to the street. This is excellent drainage- rainwater from the roof is being channeled away from the house.
Soil/Rock There are three main types of soil in Los Angeles: Sandy, Loam, and Clay. The combination that the soil is made up will determine its stability. In the Los Angeles basin, sediments can reach as deep as 10 kilometers (6 miles) before bedrock. Shaking from an earthquake in these regions can be 5 or more times greater than the shaking in nearby mountains.
Los Angeles was built up between 1920-1960, existing structures have been seasoning for the past fifty years, a good foundation indicates the stability of the soil. The closer the bedrock is to the surface the better.
Erosion Protection If you observe a lot of dirt or clay on the hillside of the property, this can be a major issue. Slope planting of species with large root systems greatly enhances the stability of a hillside and also reduces the hazard of a mudslide. Note, that there are certain varieties of plants, that may actually destabilize the hillside. The Geo report will recommend the plants species that are the best to plant. Another big plus, is if you observe a sprinkler system installed on the hillside that waters the vegetation. Watering the plants that are supporting the hillside makes sure they don’t dry up and die.
“Creep” is a term that describes when a house is slowly sliding off its foundation down the hill. Creep occurs because the property doesn’t have caissons, or otherwise has a defective foundation. Structures such as decking, and fences located on slopes can develop creeping.
These pictures were taken from a house on Multiview in the Hollywood Hills West that had creep. This house needs extensive foundation work
Pools can also have problems. Two quick ways to check how the pool is performing is to look at the edge of the pool- the waterline should be level. If the water is “tilting” toward one side of the pool that means something is shifting underneath because pools aren’t built that way. The other thing to check is if there is any cracking where the shallow end and the deep end meet- this is the common place pools crack if they are settling.