Pier Spacing for Improvised Little House

Started by Mad Dog, September 02, 2008, 04:51:23 PM

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Mad Dog

Just wanted to post this here, since I bought the plans a month or so ago.  I've been doing some site prep on the property when I decided to change the basic plan from 14x24, to 16x24. 

The question I have is how far apart to space the piers over the 16' span?  I'll be placing 5 piers 6'OC for the length of the 24' span, with 4x12 beams.  Since I'll be using either 2x10's or 2x12's for the joists, I'll be placing them farther apart than the prescribed 9'8" span, with 2'2" overhang's on the 14 span. 

Don mentioned that he has about a foot overhang with his build, and seeing as his is almost 16 feet, I was wondering if that would be good to handle the load? 

Basically 14'OC with a foot overhang on each side for the 16' span, and 6'OC down the 24' span.

Thanks in advance to any and all replies. :)
I refuse to tiptoe through life, only to arrive safely at death.

Mad Dog

Crickets.....I hear crickets......... Where's my plans support.... ??? c*
I refuse to tiptoe through life, only to arrive safely at death.


ScottA

I think it'll work but I don't like overhanging the walls off the beams. I'd go with 3 beams, well I did actualy. But if you are set on 2 beams I don't see an issue with your plan.

John Raabe

#3
The plan you have is not designed for a 16' width. You will need to upsize the beams and joists for that span. You can look at a span table for the joists but you need to do a load trace from the roof down to determine the best beam size and pier layouts.. The Victoria Cottage plan has a post and pier foundation layout designed for the 16' width. It is the expandable studio plan in that set.

Your 1' extension would be alright if you went with 2x12's @ 16 " for the joists, but you would be putting more weight on the beams than they are designed for. You could guess at it and go to a 2" deeper beam if you wanted, but I like the layout in the Victoria plan much better and it has the piers and beams under the walls.
None of us are as smart as all of us.

Mad Dog

Thanks for the response John.  So basically you're saying that if I went with the 4x12 beams, with 2x12 joists, set the piers directly under the 16x24 structure?  6' OC for the beams down the 24 foot span, and 16' OC for the joists for the 16 foot wide area.  Basically....


   x   {6'}   x   {6'}   x   {6'}   x   {6'}   x
   /                                                  /
  16'                                               16'
   /                                                  /
   x   {6'}   x   {6'}   x   {6'}   x   {6'}   x
I refuse to tiptoe through life, only to arrive safely at death.


glenn kangiser

Changing length is easy as engineering and loading is the same but extended, in even pier spacing or shorter engineered or calculated  increments. 

Going wider changes the calculations and loading completely and makes it into a different animal, hence John's recommendation of the Victoria plan which is designed 16 wide and calc'd for it.

I know John has had some issues to deal with lately so may take him a bit to get back to this.

Since this is a deviation from the plan design there is some guess work involved. :)

"Always work from the general to the specific." J. Raabe

Glenn's Underground Cabin  http://countryplans.com/smf/index.php?topic=151.0

Please put your area in your sig line so we can assist with location specific answers.

John Raabe

That should work for a normal snow load. This is without doing the engineering calcs on your modifications. 8) What you have drawn is similar to the 16' wide studio foundation and floor framing. You could go to 2x10 floor joists if they are not cantilevering the wall loads.
None of us are as smart as all of us.