of Project Here
Selecting a Location
1.) If your adding to an existing structure, it will be necessary to
drill and dowel
into the existing foundation. Call your electric or gas company and find out who to call to have
your property checked for underground utilities if you don't know already.
2.) Refer to these illustrations
for how to setup a batter board to level this type of foundation.
3.) There's more than one way to do this, some might say one pour for the footing and another pour
for the wall. I'm going to describe one pour mainly because that's the way I do it. Local codes
will be the determining factor I'm sure. Maintain 18" minimum clearance under floor joist and 12"
minimum under wood beams. Here are some
foundation illustrations, click on the links provided there to see several pier and beam examples.
4.) Once you've setup the batter board and the string line is square, drive 2x4 stakes every 2' feet
around the perimeter and one near each corner using the string as a guide. Start by holding a
level next to the stake as you drive it in so that the bottom of the foundation will be plumb with the
5.) Drive stakes just below the string, and deep enough to be secure.
6.) Fasten forms with #10 duplex nails driven through the stakes and into the form boards, the
ends of the form boards should start and end at the center of a stake. Fasten your form boards around
the perimeter starting at the top using the string as a height gauge. Stagger the ends of the form
boards on each row. It may be necessary to cut the bottom row to fit snug to the ground. Install all
forms and secure to each stake, secure corners as well. If you allowed for a layer of plywood on the
inside of this form, cut and install it now.
7.) Dig a 10" wide 10" deep trench around the perimeter next to the inside
of the form.
8.) Drive 2x4 stakes every 2' around the perimeter, 11-1/2" away from the inside of the
first form. Setup the inside form level with the outside, repeat steps 3 thru 5.
9.) If your plans call for a beam in the center of the floor, you'll need to purchase some form tube at
least 8" in diameter. If the center beam is inline with joist, piers will be the same height as the beam
walls. Otherwise, deduct the height of the center beam from the height of the beam walls. Setup your piers
to this height. First setup a string by locating the center of the foundation and drive a stake into the
ground next to the inner form at both end. Attach the string and measure the required distance from pier
to pier your specs call for and drive a stake to mark each pier location. Dig each pier hole an equal
distance into the ground as the pier height is out of the ground up to 3'. Depending on the diameter of
your piers, drive two to three #4 rebar into the hole long enough to reach within 2" of the finished
height of the pier. Secure the steel rods together by cutting some short pieces of rebar and tying with
wire ties in two or three locations. Cut each form tube a couple inches longer than what is needed for
height. Drive two stakes near each hole and cut 2x4's long enough to plumb and brace the form tubes.
Screw through the form tube and into each brace to secure. Use your water level and mark the height
of your concrete on the outside of each tube. Drive a screw through the form tube at this mark to serve
as a height gauge for pouring.
10.) If your plans call for a beam in the center of the floor and it is located under the joist, a pocket
in the concrete to set the beams in may be necessary. If you have a double beam to install, cut two 2x4
blocks 1-1/4" shorter than the height of your beam. If you have a triple beam cut two 2x6 blocks 1-1/4"
shorter than the height of the beam. The 1-1/4" will allow for your sill plate and a 1/4" metal shim under
the beam. Nail the blocks together to form one block measuring 3" thick. Locate where the beam would meet
the concrete and nail the block flush to the top of the form. This will give you a pocket 3" deep for your
beam to rest on.
11.) Measure 12" from a corner and drive two #3 rebar stakes cut 6" longer than the height of the
form measuring from the bottom of the trench. Drive the first at 2-1/2" away from the outside form
and the second at 2-1/2" from the inside form. Repeat this every four feet on each side starting and
ending 12" from a corner.
12.) Using 20' lengths,
bend a piece of #5 rebar about 4' from the end at a 90 degree angle. Set this piece in a corner
and lay between the outside rebar stakes and the form, attach it to the steaks with wire ties about
3" off the bottom of the trench. Bend another #5 rebar at 4' and install in the same corner directly
above the first but because the ends of the rebar should be staggered and not break one over the other,
install with the 4' section facing the opposite direction.
13.) Bend two more pieces, this time at 8', and install at the same height as the first two bars accept
these are installed on the inner stakes. Be careful not to break the ends one over the other. Install
rebar around the perimeter overlapping bars a minimum of 40 diameters, or 25" for #5 (5/8") rebar. Steel
should be within 3" of the bottom and top. If rows are farther than 20" apart install another inside
and outside row of #5 steel in the center.
14.) Drive a 2x4 stake about 4' out from each form stake, drive till it is very firm and deep into the
this example, measure for a 2x4 brace to lay directly on the ground between this new stake and
the form stake. Next, measure for a 2x4 to set on top of the first brace and extend to the top of
the same form stake. Nail securely with #16 nails. Brace each and every stake on both forms in the
16.) This should be poured using a concrete truck. With a few wheel borrows, shovels, some helpers
along with the concrete trucks chute, it's a snap. Pour fairly wet so concrete will flow well.
If your form is taller than 24" from the ground in any given area, to keep from blowing out your
forms, pour about half full and move to another location to let it rest for awhile. When returning
to fill the remainder, use a piece of rebar and push it up and down along the outside and inside
of the pour to help mix the two together. After forms are filled, float with a hand trowel and
install the foundation bolts. Bolts should be located 18" from a corner and every 6' around perimeter.