Earthquake retrofit???

[643gwozdz]

Hello -

I own a single story house built in 1926. No basement, but a crawlspace. The foundation is built of blocks. I have read that there is not much you can do to prepare a block foundation for earthquake motion. Has anyone heard otherwise?

Are there any other framing modifications that I can do to prevent this house from coming down on me during a big shake? I don't need in to be inhabitable after a quake, I just want to have enough time to get the family outside before the roof come down, etc.

Thanks very much for your advice...

 

[inspectorD]

Only an engineer on site can answer that question. Depends on condition of block,the building itself and soil type. No DIY answers on this one.

 

[joecaption]

Most if not all of the earthquake damage prevention would be done while the house was being built. Tie downs in the corners of the wall. inside corner bracing, rebar in the blocks, straps to hold the foundation plate to the foundation, hurricane ties from top plates to rafters, ect.
The suggestion to go talk to an engineer is a good one to check out anyway.

 

[nealtw]

Our engineer had us use ancher bolt and brakets to bolt the floor joists to the footing but I wouldn't start without the engineer.

 

[AndyGump]

You can do all kinds of things yourself to the foundation to help you sleep a little better at night without involving an engineer.
The things you do may or may not help in an earthquake but as long as you don't corrupt the integrity of the original construction you won't be worse off for having done something yourself. I think it would be prudent to involve a foundation company that has experience with this kind of thing though. They usually have engineers on staff to spec things.
Now usually the kind of things they will recommend are things that involve special retrofit hold-downs, strategically placed strapping and ties that involve opening walls and such.
You could theoretically do the work if you have a plan of attack from an engineering company though.

Andy.