How Safe is a Post and Pier Foundation?

[Kri]

I just happend upon this document http://www.countryplans.com/foundation/index.html which made me wonder:  In the Pacific Northwest, on a windy shore, is a post and pier foundation safe?  Or what can be done to make it safer?  If the post and pier foundation plan is stamped with a structural engineer's approval, does that cover all of the bases?  Or??

[Kri]

Oops:  What's the difference between post and pier vs. post and beam foundation?  I might be confused on this terminology. 

[ScottA]

A post is really just an extension of a pier so "peir and beam" is what you're after. Peir being the vertical and beam being the horizontal. Properly braced and anchored to the ground it's as good as any foundation IMO.

[Kri]

Thanks for the feedback, Scott.  I appreciate it.  I guess I've seen so many challenges with concrete foundations (water, mold, access, rodents, cracking) that it seems no matter which direction one goes, there are pros/cons.  It's not always easy to figure out which option is ideal.  So I don't know if I'm just getting cold feet because I'm so close to building (what have I forgotten to consider?!) or if I'm being too cavalier about trusting the post option, even though it will be stamped by a structural engineer.

[glenn kangiser]

If the engineer stamps it he is guaranteeing it will hold and bldg departments usually accept it, no problem - with possibly asking for clarifications.

[MountainDon]

Pier/post and beam foundations are good, but, as John has pointed out someplace before they may not suffice or be recommended for earthquake or hurricane prone areas.

If in doubt run it by the local inspectors.

[Kri]

Glenn,
Thanks a bunch.  It sounds like I should ask the engineer to what wind capacity it is guaranteed to hold at.

MD,
Thanks.  The local inspectors have been great about the pre-questions so far, so it makes sense to toss this one at them.

And guess what...
It appears (in the years since I last had to worry about this), our area has greatly reduced their earthquake coverage.  Some companies won't insure anyone and if you had EQ insurance, when your renewal is up, they now let you know that you'll need to seek the EQ portion elsewhere.  If you can find the elsewhere.  This is yet another reason to keep it small and affordable...and why I'd build even smaller and simpler should that ever happen...goodness.

[Jackson Landers]

Go to any beachfront community in American that has to regularly deal with extremely high winds, storm surges and other extreme forms of stress to building foundations and tell me how every single house is built.

On wooden posts.

[Kri]

JL,

I tend to see that too!

I just talked with the county and found out how they review/verify things:  Basically, they ensure the engineer calculated correctly for the local wind/earthquake zones ((of the specific site, too)) and that it's all transferred to the plans correctly and that the plans are followed onsite.  I can request that they be bumped up, structurally, if I want to make sure things are extra safe.  It might be as simple as making a few nail/hole/bracing changes or it might be a little more intense, but the time to do it is now, if I want it to move smoothly through the process.  Phew.

[CREATIVE1]

We're not allowed to have this foundation in Mason County, Washington.  Tried hard, because it was a real shot to the budget.