Monday, June 25, 2007

While the frame is not yet finished, it is time to pour the small pier foundation for the cabin. After two years of searching and waffling back and forth, I finally decided on the precise spot and orientation for the cabin, which, it turned out, was the exact spot I had originally decided on when I first hiked on the land prior to buying it. Funny how it all worked out. The location is not without some drawbacks, but I think it is one of the best locations possible on the land.

After some planning and measuring and staking out the location of the piers, I spent a couple days digging the holes. I wasn't sure what I'd find, but based on the granite rock outcroppings, I figured that I'd hit bedrock quickly. I was right.

This made things easier and better, since the piers can be poured right on bedrock, making a very, very strong foundation.

I bought about 4,000 lbs of concrete, some 12" sonotube, and some #4 rebar for the task. Since there is no water source at the cabin site, I brought about 80 gallons of water in a plastic rain barrel, a 20 gallon trash can, and misc. containers. Hauling this to the cabin site obviously took several trips my trusty Jeep. :-)









My daughters helped me haul up all of the stuff. They liked the pier holes!







I created short batter boards using stakes and 1x4 scrap lumber. I used this to layout the center of the piers over the top of the holes. I then offset everything by 6" to the outside. This created nice square intersection of the lines for the outside of the frame.

Lynne stopped by with Walden and helped me make some final measurements and adjustments to the line layout. Some parts of this project are just really hard to do alone, so I really appreciated the help!

The piers are oriented in the holes such that they barely touch the lines. We used line levels to assure that the piers themselves were level.




Here, you can see the formation of the rebar and wire mesh that Peter recommended to re-inforce the piers. I liked this setup, especially the bending of the #4 rebar and the way it was worked into the wire mesh.




Peter and his family dropped by. Fortunately for me, Peter stayed several hours to help. Mixing a bag of concrete with a measured amound of water in a small tarp really was a time-saver vs. using a wheelbarrow and shovel!



Sadie and Willow even helped mix concrete for awhile (while Lisa took some photos).




When the pier was mostly poured, we buried the metal tie-down strap into the concrete. It has a 45 degree bend in the bottom 1/3 of the strap that gets mixed into the rebar and wire mesh. This strap will get nailed to both the sill plate and the principle posts, and will really secure the frame to the foundation.





Below is the finished foundation. All six piers finished in one day. There is no way that I would have had this done so quickly if Peter hadn't offered his help. I would have been lucky to have finished 2 or 3.

I'll put small sections of pressure treated wood plank between the concrete piers and the larch sill timbers. This will serve two purposes: keeps the sill timbers from directly contacting the concrete foundation (and rotting prematurely), and it will allow me to plane the pressure treated pieces as necessary to get the sill timbers to be perfectly level.

I can't wait to see the timber frame on this foundation!


1 Comments:

At 1:45 AM, Anonymous SteveR said...

This is an interesting way to do this. I live in an earthquake zone and tying the sill to the foundation is important.
The pressure treated wood will eventually rot. Does this method lend itself to replacement of the pressure treated 'shims'?

 

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