Replies

1. 
   bgibson11 | Aug 24, 2011 08:27pm | #1

   forgot to mention

   I forgot to add that the camp is going to be one-story with 8' walls. Roofline is going to be cathedral.

1. 
   calvin | Aug 24, 2011 08:57pm | #2

   bgibson

   How'd you come up with the design of 6-8 poles with the beam sizing and the cantelever of 1/4 the span?

1. 
   bgibson11 | Aug 25, 2011 06:23pm | #3

   I don't have a design - that's what I need help on.

   I know we are going to use at least 6x6 poles and at least 2x10 or 2x10 carrying beam. And, I know a rule of thumb is that a cantilever must be limited to 1/4 of the backspan...

1. 
   Piffin | Aug 28, 2011 08:32am | #6

   You need to forget this "rule

   You need to forget this "rule of thumb thing if you want to enjoy this camp.

   For instance, the 1/4 length span deal....That is for an open deck, not structrual loaded.

   Forloaded with walls and roof abpove, the max cantilever is the depth of the floor joist, so with 2x12 joists you can cantilever 11.25"

   There is no rule of thumb for number of posts. The fewer posts, the more strength and size you need in the beam. As you describe a doubled 2x12 beam for all this structure, you might need the posts to be 6' apart.

   But that is working the design backwards, IMO. Set eight posts and then size the beam to the span.

   There is a way to do this with six or four posts, but that is not practical for you.

   What is your snow load requirement there and what building permit requirements are you under?

2. 
   CMSART | Aug 25, 2011 06:54pm | #4

   If I understand your post, you want to carry a roof/ceiling and one center bearing floor on  a built up 2 x 12 girder supported by a wood pier at each end of a 24 foot span?  Without knowledge of your local conditions & codes your piers/girder design sound inadequate to carry the loads. 

   Your pier and girder sizes and spans would have to be calculated to support structural loads, including snow loads for your area.  Check your building codes for specific requirement in your area.   Better yet, talk with a engineer.  It's not a complicated design, however there's just too many unknown variables to give you a quality answer.   

   Muck

3. 
   TLE | Aug 26, 2011 06:06am | #5

   8 poles minimum

   Typical spacing would be 8' oc.

   You don't mention the height the poles will be sticking out of the ground - how much bending stress they will be subject to. If only out of the ground a couple of feet, 4x6 would be plenty.

   Somewhat more critical is the size of your footing pad. In southern Michigan I would go with 18-20" diameter by 8" thick to a frost depth of 42".

   Terry

1. 
   Piffin | Aug 28, 2011 08:43am | #7

   "more critical is the size of

   "more critical is the size of your footing pad"

   In structural work, no one element is any moire critical than any other, IMO

   A chain is only as strong as it's weakest link.

   But what the OP needs to understand is that the whole thing must be designed to handle the loads it wil be subjected to. First he needs to supply info about area loads requirements - and when it comes to footers, what the soils bearing capacity is. Footer for rock is far diff from footer on clay

4. 
   Pinkyringz | Sep 15, 2011 04:36pm | #8

   I built one like this on private property for a private guy for cash....it was his design...his pole spacing was was every 4 feet....that thing is still standing...yours will work....24 by 14 isn't that big.....you can get away with 6 foot spacing for your poles but i would go with 4' spacing, it will make sheathing much much easier....you can overhang about 16" on each side at max....but your better off with a 12" overhand and then add on a porch roof as i am assuming thats why you want a cantilever...best of luck chum!!