20x32 post and pier footing and beam size questions

[soot001]

I'm building a post and pier 20x32 cottage, my lot has been built up by boulders so digging footing will be tricky. Any suggestions?  I figured I'll use 3 rows of 5 piers length wise, but I'm unsure of the beam size and assume lenth of the beam should be 2 @ 16'. I plan on using 2x10x20' joists going across the entire width. The only load bearing walls are the exterior. As far as the beam size for the length, can anyone suggest options as I know less footing piers= bigger beam and more piers= smaller beam. I'd like to see which is cheaper in my city. Any suggestions is greatly appreciated. And any reccomendations as far as a more cost effective way of footing and beam size options is a big help. Thanks.  

[glenn kangiser]

Welcome to the forum, soot001.  Are you using John's plans?  It is not a requirement, but I think beam sizing and foundation options is included in them.  Considerations would be your local area requirements.  What area are you located in?

There are a couple places in your profile you can put your location to help people think of things that may apply to your area.  The personal text line is one - signature is another I think - going from memory-- the location option doesn't actually show up on your posting.


Also - is that fill the boulders are in? Was it well compacted?  Undisturbed native soil is the best to build on if possible.

[MountainDon]

  soot001. As Glenn mentioned the number of posts is not driven solely bt the beam size. The load bearing capacity of the soil enters into the equation as well.

The total load on the beams/piers is also determined by the type of the structure; single story, loft or no loft, 1 1/2, 2 story, snow loads and the like.

One other question that could be of concern is whether or not you are bound by any building codes or rules. Some places will not allow piers/posts.

One of the nice things about plans like John's is that they come with a variety of solutions for the foundation and they are conservative in design. Country Plans

[soot001]

I live in Kula, Maui (Hawaii) so we have no snow loads and this land I'm building on has no restrictions as far as post and pier. This is the second house on this property and so for the most part the piece of land I'm building on has been built on and compacted for a concrete slab house, I'm just wanting to do post and pier as a preference. It will be a single story house. THanks for the help.