Yeah, I figured the soil, being pretty rocky, or “boulder-y”, wouldnt allow many basements or cellars. In North TX where I lived for 30 years, folks didn’t have them either. The soil there is a hard, poor black clay. It is nasty stuff, and can wreak havoc with house foundations, especially when the weather cycles between rainy spells and blistering droughts.
In tornado prone areas, a lot of folks in OK and TX build concrete reinforced safe rooms inside of their houses. They were developed because if an F4 or F5 hit your house, it would wipe it clean off the foundation. So getting in the tub or closet did no good.
The odds of that happening are pretty low, but I’d you lived in Moore, OK, it prob would be a wise move. Moore had an F5 with 300+ mph winds hit it in 1999, and another F5 hit it a few years ago.
So, every place has its own natural hazards. But, man, Cali seems to have just about all of them!
Actually, most of our soil here is not rocky. I happen to live in a boulder field, but that is the exception, not the norm. The reason you won’t see a basement here in S. California is due to our earthquakes. Can you imagine being in a basement during an earthquake?? Not the place you want to be. You can build a house with a basement, but that basement would cost you about $100,000 alone, due to the very strict and extensive codes around a structure with a basement. Just not economical, not safe, and no real reason to have one here
edt: Jeepers, Dood, I see I just said the same thing Richard did, sorry! Well, at least you know for sure why we don’t have basements here, lol!!
No worries, I knew you were in boulder town, and had read about other folks’ issues with big rocks in their soil, so you know, I extrapolated for all of Cali. I didn’t know about all the regs, but it makes sense.
Oh well, so no twisters to worry about, but you still get quakes, wildfires, mudslides, sink holes, 500 year droughts followed by 500 year deluges to look forward to. Plus, Jerry Brown. Ah, the price of living in paradise.
Do new homes there have pier and beam supports, or are they usually on slabs? As I mentioned about N TX, the newer homes use the slabs, and the contracting and the expanding clay soil makes for interesting interactions with those. Needless to say, foundation repair is big business there. That’s also why there weren’t a lot of folks I knew of that had in-ground pools.
When I bought my first house, the owner’s manual for it talked about running soaker hoses around the perimeter of the house to give the soil a bit of moisture during extended dry weather. For certain times of the year, some of the interior doors wouldn’t latch shut because of the subtle shifting of the foundation.
My area just happens to have a lot of granite. Richard, who actually lives pretty close to me, does not have the same soil make up as me. I’m in the hills, and this area happens to have a lot of granite. You can drive 7 miles towards the ocean and be on a combination of sand, sandstone and clay. Completely completely different. That is California for you. Not only is our soil substrates very different, so are our microclimates. I’m in a small pocket that gets way more ch that just a mile east, west, or south. Yes, we can get all those natural disasters, but not in all areas For example, no mudslides for us here, or sink holes. Earthquakes, droughts and wildfires are our biggest natural disaster at my place, but Richard would not be threatened by wildfires. So, think we’re pretty even with everyone else in the USA with regard to threat of natural disasters. We have far less of a chance of being hit by an earthquake, that folks in the Midwest do with tornadoes, tornadic activity, horrible damaging hail storms, etc. So, all in all, it’s really a pretty safe place to live.
Most all homes here are built on concrete slabs. Some homes in areas where the geography might cause the home to really shift in an earthquake or during extremely heavy rains (I think immediately of Portuguese Bend on the Palos Verde peninsula), might need a different foundation, but the vast majority of homes built in S. California are on a concrete slab.
I’m happy with my wood framed house on a raised foundation with a crawl space. I’m about two miles from the epicenter of the Northridge quake. This house racked, bounced and swayed a bit, but no cracks anywhere, no fallen chimney or such. Lost a lot of teriyaki sauce though, but thankfully all the spilled oatmeal soaked it up pretty well.
Yup, we do have a handful of homes on raised foundations with crawlspaces, though not many. You’ll see some in Pasadena/Monrovia/Glendale/Arcadia area, built in the 1910’s-1930’s. And, my neighbor’s house down the street (custom home) is built on a raised foundation with a crawlspace. Which in my area is really unusual. I remember when I first walked into her home, and started walking across the wood floor. You could tell immediately it was on a raised foundation due to the sound you make when you walk across the floor. I think their house is the only house in our neighborhood built on a raised foundation. Slab construction is cheaper, which is why it is seen most often. The other really great thing about being on a raised foundation, is plumbing repairs are way easier, as you can actually get to the pipes without having to bust out a bunch of the concrete slab.
Homes built on granite/bedrock (which isn’t going to move much, unless you’re at the epicenter), versus flat soil which is subject to soil liquefaction during a quake. When I was growing up, we lived in Huntington Beach in an area that was reclaimed swamp/salt marsh land very close to the ocean. Lived there during the Sylmar quake in 1971. It was like being in a bowl of Jello. Pretty scary.
It depends on location, type of quake, and composition of the hills. Shock waves travel faster through solid rock while long rolling waves are perpetuated in deep alluvials.
It makes no economic sense for developers to construct basements in the tract homes which are prevalent since World War 2. Consider the labor & material cost of the engineering, excavation, construction and back filling of basement retaining walls. It is much more economical to just add a second or third floor to a wood framed structure.
The faster, shorter amplitude shear (shock) waves create less damage than the slow, large shear waves. Which is why being on granite/bedrock is safer. The shear waves travel quickly and are absorbed in the bedrock. For me, in my hills, we’re relatively more stable. The absolute worst soil structure is sandy soil with a high water table = Huntington Harbour area (N. Huntington Beach on the coast). That triggers the soil liquefaction phenomena, which will shake your house down. The soil basically “liquefies”, turning into quicksand. If your hills are mostly sand, then you’re at more risk for the shear or seismic waves to cause damage as they will travel more slowly and not be absorbed well, with the waves being transferred up into your structure. If your hills are mostly rock or have a bedrock structure, less damage.
In CA or other places where there is no frost line to worry about that’s true. If however you need to go 4 or 5’ to get under the frost line, then going the rest of the way to make a full basement is not that much more…
Depends on location. Sitting on top of bedrock a few miles from epicenter of shock event on a shear fault will at the least send the contents of your home slamming into opposite walls or through windows at a high rate of speed … and at worst reduce your home to large splinters in a matter of seconds.
I agree. Here in California modern tract homes are frequently built on top of a post tensioned slab on grade foundation which also serves as the first floor of the home. Very fast and efficient.
Yup. Think I mentioned that exact thing in my previous post [quote=“hoosierquilt, post:552, topic:3613”]
Homes built on granite/bedrock (which isn’t going to move much, unless you’re at the epicenter)
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Isn’t a lot of the San Fran area on reclaimed land? If I remember those areas were especially hit hard during the Loma Prieta quake, because of the liquifying factor? I still remember the scenes of the pancaked elevated freeway in Oakland and all those flattened cars, just horrible.
… It’s safety from earthquakes. You can build basements here but the structural requirements for a building permit are vigorous.
