How You Can Strengthen Your Home for the Next Big Quake

[Wrightwood]

[pdf]http://www.cert-la.com/BAS-How-You-Can-Strengthen-Your-Home.pdf[/pdf]

[KW]

Okay, so what the heck is a cripple wall?

[Elk]

Okay, so what the heck is a cripple wall?

On a raised foundation home an example would be a short wall that is below the floor level and has the floor framing resting on top of it. In older construction these walls were not sheated with plywood. As a result there is not as much shear strength. In older homes it is recomened that you add the plywood and nail or screw it off. I do not remember the code for the nailing but it is quite close together, especially at the edges of the plywood sheets. This keeps the walls together and lessens the effect of side to side movement.

I hope that helps??

[Wrightwood]

Here's a good article like Elk described:
http://www.mcvicker.com/twd/apa/eqguide/eqguid05.htm

[ChattyCathy]

My neighbor told me that my house is not secured to the foundation. 

I wonder what it would cost to have someone do the necessary things as listed above.  The problem -- I've never been able to get any of the local handymen in town to even return my calls, let alone come to my house.  I highly doubt it's something I can do on my own.

[KW]

Ah, okay, thanks for the explanation of the cripple wall. My house is on a slab, so I guess I don't have to worry about that. And since my house was built in '73, it should be bolted to the foundation.

[RobertW]

Foundation?  What is that?  Our place was built in 1926 and I don't think they knew about foundations.  Our place was built on the ground.  Here it is in 1939:



By 1949 Meluso and my grandfather had managed to build a fireplace, a porch and somewhat of a rock foundation underneath most of the place.  They actually put the foundation in place under the existing cabin.  A new bedroom addition in the 1960s was built on a foundation.



When the big one hits we just expect it to jump all over the place and fall apart.  We just hope to get out of it before that happens.  Then it will be a good time to get rid of the debris and start all over.  Sounds like a plan...

[FIGHT ON]

I am a

I do not remember the code for the nailing but it is quite close together, especially at the edges of the plywood sheets.

8d common 4" on the edges and 12" in the field.
5 ply structural 1.
50% on 1 story, 70% on 2.

[BikingBrian]

Note that newer places will have crawl spaces made of block walls and so you won't have to worry about the problem described here.   My "old" cabin was built in 1963 and had block walls, but my "new" cabin was built in 1955 and has cripple walls.

I did the shoring of the cripple walls myself last fall.  Photos and links to the standard plans are here:  http://briandesousa.com/blog/?p=9  Too bad I didn't get any discount on earthquake insurance for doing so.

Here's a link to the standard plan:  http://www.ladbs.org/rpt_code_pub/anchor_bolting.pdf
Here's a link to the City of Oakland guide:  http://www.oaklandnet.com/earthquake/GetRetrofitHandbook.pdf