First cabin build starting soon 24x24

Started by Nimitz, May 31, 2013, 10:40:43 AM

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Nimitz

Hi new member here posted this on an other forum but found this site while looking for foundation advice so I will post it here also.

I am going to be building a 24x24 cabin this summer this weekend they are going to be building the road and clearing my land.
At the beginning of next week they will be putting the foundation in.


Here is what I am doing as of now
-Piers are 8'' Sonotubes 6' in the ground and 3' above with 4 bars of rebar.
-Screwed to the piers will be treated 4x4 12' long
-On top on the 4x4 crosswise will be 2x6 8' long
-To keep the precise 24'x24' size I will be cutting the 2x6 on the ends by 1-1/2'' to attach the 2x6 to box the framing of the floor
-The floor will be covered staggered formation by 4'x8' plywood.
-As of now the bottom of the floor will be covered in plywood also



Dimensions
The 2 center piers on the sides walls are 96'' apart center to center. The corner piers are 89'' from the middle side wall piers center to center. The piers in the center of the cabin are 137'' center to center from the side wall piers. The dimensions of the corner piers center to center is 274''. This leaves me with 3'' from the end of each pier to the end of outside wall.



Questions
-Do I need to use Brackets to hold the 2x6 together on the ends.
-How should I hold the 2x6 to the 4x4
-The 2x6 that meet end to end should I attach them together in any way
-I am in Quebec should I insulate the floor and if I do should I then cover the bottom of the floor with plywood.
-Do I need to put and cross beams to separate the 2x6
-I think my foundation is strong enough since the company that does the metal piers screwed into the ground only wanted to put in 9 piers for a 24x24 cabin.
Well those are todays Questions. I am sure my father will have some answers but I would like a second opinion.

SouthernTier

Here's a good discussion about girder sizing and spacing:

http://countryplans.com/smf/index.php?topic=10511.0

Span tables for joists for floors:

http://publicecodes.cyberregs.com/st/ny/st/b400v10/st_ny_st_b400v10_5_par014.htm

(that's for NY, but would apply in QC as well I would think).

Seems like you are undersized on your girders.  Joists should be strong enough but somewhat bouncy.  But that's just a quick-n-dirty look.  Take a closer look for yourself.

Definitely need to insulate floor.

Cross beams?  by that do mean blocking?  Typically yes.

I would look into simpson brackets for holding the joists to the girders.

Also, it has been said here "design from the top down".  Can't really comment on a floor/foundation without knowing what is sitting on it.


NavyDave

Nimitz,

I think the 4x4s may be a bit small for a 12 foot span. I believe you'd feel quite a bit of bounce with that span. check those links that Southerntier gave you they are good resources.

Also a suggestion for your floor joists would be to stagger them using a 16 footer then an 8 footer then alternating the 8 footer and 16 footer. That would really help tie the floor together for you.

Insulation for a vented floor in Canada would be a must I'd think, depending on the use of the building. If it's a full time residence you may want to upsize the floor rafters a bit to give you more room for insulation. For the few hundred bucks extra for 2x8's vs 2x6's I think you'll be happier and end up with a stiffer floor.

With that said  w* I look forward to following your progress.

grover

I tried to follow your description and I got lost after the sonotubes.  I'm not sure I follow the spacing of the sonotubes.  The only thing I got on that was 4 piers on a wall each 8 ft apart.
Can you attach some sort of sketch?

I would think if you do a 24' x 24' you should have 3 rows of 5 piers.  Maybe 4 piers down the middle.

How many floors?  What kind of roof system and pitch?

Nimitz

Some more info.

The cabin is 1 story plus a loft so 1-1/2 floors.
The walls will be 10' high in the main cabin.
The loft will only cover the back half(12') of the cabin with the front half open to the roof.
The rafters will be made and installed by a roofing company.
I will be using the cabin max 16 weekends a year. For the next 2 or 3 years most likely 4  to 6 weekend .

Sonotube spacing




grover

Your pictures are not showing up for me. ???