Pier/Post Diagram for the 20 x 30 1.5 story cabin

[snross98]

Hi, I just received the plans for the cabin listed above.  All of the outside pier/posts were marked and measurements were included but I'm wondering about the internal pier/post requirements?  Can I span up to 10' across the cabing with I joists, which would allow me to get away with only 1 row of piers down the center of the foundation?

[John Raabe]

The beam and pier foundation plan on sht. 1 has beams on the longer outside walls and the I-joists spanning the full width of the building (20') with no support beam needed in the center. There are two piers (no beam) at the center of each end wall. They add stability to the end joist and wall.

Should you want to go to the extra expense and do a full centerline beam with piers you would not need I-joists for the floor as 10" can be spanned by 2x8 joists or even 2x6s.

[snross98]

Thanks!  That's exactly the information I was looking for. 

[craigb]

Question, I'm still in the planning stages, looking at a 24x36 one story with either a 10:12 or 12:12 pitch roof on post and piers in Colorado. Do you think it's easier to do the whole span with I joist, or three beams of doubled 2X12's one down the center with joist overlapping the center beam? I'll be pretty far from the closest town, so may have a friend bring up his medium size cement mixer, the contractor type. This also may be a lot of work since I figure at least 36" to frost line, and the amount of concrete we'd need to mix. Also, what's the best way to the the post, sink them in concrete, or bolt them to the piers? I've seen it both ways here, I've always hated putting post in concrete, but might resist flex and twist more.

Craig

[John Raabe]

At 24' width you will want/need a center line bearing girder to support the 12' spans on the joists. If you are working from one of my plans you will find information there on the pier options, brackets, etc. Depending on the site and how high your piers or posts will be, you may be able to cross brace for racking resistance. But for a home this size in snow country you will want a solid stable foundation. Pressure treated wood crawlspaces or basements are a good option where concrete is costly or a hassle. That information is in the Universal Cottage plans.

[craigb]

At 24' width you will want/need a center line bearing girder to support the 12' spans on the joists. If you are working from one of my plans you will find information there on the pier options, brackets, etc. Depending on the site and how high your piers or posts will be, you may be able to cross brace for racking resistance. But for a home this size in snow country you will want a solid stable foundation. Pressure treated wood crawlspaces or basements are a good option where concrete is costly or a hassle. That information is in the Universal Cottage plans.

Thanks John, wasn't thinking, originally I was looking at the 20x34, the went wider. I don't have any plans yet, the wife and I are still looking at options, between the 1.5 and a single story. But a question on the 20' would I joist typically be cheaper than the extra beam in the middle?

Craig

[John Raabe]

It can vary locally with soils and lumber prices. I-joists are special order in some places. If you want better (deeper) floor insulation and the piers will be deep and expensive to build then the I-joist system will usually be more cost effective. If you are building in a milder climate with shallow set piers then the standard joists with the center line bearing will likely be cheaper.

The I-joist system has fewer parts and is quicker to put together.