Excavation and Footings

              On October 30 the heavy equipment arrived to begin the excavation.  It was finished on November 5.

Notes regarding the construction camera: I changed the exposure rate several times in an attempt to find the best way to document the process.  I ended up with more exposures per minute, a five-second interval. I deleted early morning and late afternoon times when nothing significant was happening in order to shorten the film. I also had to move the camera as excavation continued.

A link to the construction camera footage of the excavation is here:

Excavation

The footing subcontractor pronounced the excavation a success.  The maximum deviation from the desired elevation was less than 1.5 inches.

               Once the excavation was finished it was time for the installation of the FastFoot forms.  The final design of the foundation included 36” wide footings, 12” deep, on the west side and 30” wide footings, 12” deep, for the remainder of the foundation.   The thicker west footing was required because there is a stud wall inside the SCIPS wall on that side.  We decided to add 6” in width on portions of the south in order to support the deck; our goal is to support the deck as an independent structure rather than using the SCIPS wall as a structural member.

                Basic information on the FastFoot system can be found here:

http://www.fab-form.com/fastfoot/fastfootOverview.php

http://www.fab-form.com/fastfoot/fastfootInstallation.php

               This video gives an overview of the setup and concrete placement*:

FastFoot Footings

                The finished FastFoot fabric, bracing and penetrations before placement of the concrete: 

Warning:  Wide angle lenses make straight lines look curved!!

East side from the north

 West side from the north

Transition from 36" to 30" footing

Footing penetration detail:  radon mitigation

Close-up of Radon mitigation pipe

                The pour in process:

Beginning of the pour

Screeding

Final level check

              

  Completed footings:

 From the northwest

North side from the west with shear wall

Mudroom from the north

Center of the south wall

Sanitary line on south side

                The verdict from the subcontractor:  once they have worked their way through the learning curve it will be quicker than the standard dug footings.  Setup takes some time but it's easier dealing with the rebar when everything is above ground. 

Three notes for future reference if anyone is interested in using FastFoot: 

1.       Stanley, the subcontractor, said that he originally underestimated the amount of concrete necessary.  It bulges out below the bracing (FastFoot's technical term is apparently "pooching out") so he said that you need to calculate the concrete needed based on the outside of the 2 x 4 bracing, not the inside dimensions.

2.       They ran into one problem close to the end, when the final 2 x 4 (you might know it!) twisted off the bracing.  They were able to get everything back level by using leverage to move it back into place and then adding additional bracing.  The FastFoot installation instructions tell you to use two nails, at different angles, to hold the bracing.  He used three:  one double-headed scaffold nail and two ring-shank nails.  After talking to Alton it looks like one nail at the center of the bracing and a hex-head screw at the top might be a better solution:  the screw would be stronger than the nail at preventing twisting and would be easier to remove.

3.       Alton noted that contractors who are interested in using the FastFoot system on an ongoing basis might want to investigate metal stakes such as these:  http://www.marshallstamping.com/nail_stakes.html  They are reusable and penetrate the ground much easier than wooden stakes.

*             In most cases I have deleted long stretches of inactivity.  However, in this case I preserved the two-hour wait for the concrete truck in order to give a true sense of the day’s flow.