you have the corners of your foundation squared and your string
set, you will need to set your outer and inner form boards.
You will need to make sure that these boards are level from
side to side and front to rear. Always start forming from
the high side to the low side.
Your form boards need to be strong enough to withstand the
pressure of 3500-PSI concrete. We highly recommend using 2
x 10's for the outer batter boards. Forming the keyway is
the key element to having a level foundation. You can make
the trough using materials that can be bought at a local building
supply. You want to make your key way form using (example
2 x 4 x10, wood screws, and ½" plywood). First turn your 2
x 4 x 10's up on the edge separating them so that they are
9 ½" apart.
Second, take a piece of ½" plywood 9" wide x 10' long and
attach it to the bottom and top using wood screws. (See illustration,
Third, take 2 x 4 x 24" and attach to the top of the formed
box in 3 locations 9-10" in from each end and one in the middle.
Allow for 5" to outside form and 3 ½" to inside form. This
will support your box by hanging it the same level as the
top of the batter boards. (See illustration , Picture 4 and
Note: By making plywood
approximately 1" narrower than 2-2 x 4", this will keep the
concrete from getting caught on top of the plywood and holding
the plywood in the concrete. Make as many of these trough
forms as necessary to go from one end to the other of your
foundation. Set the trough forms on the outer and inner form
boards and attach, using wood screws. (Remember the pressure
from the concrete is very strong so you will need to make
sure that it is secured to batter boards or it will push up
when pouring concrete.
To form End wall step down (Illustration B, overall and photo)
First, place your outer form batter boards level from side
to side. The distance between them will be 12". (Note: If
you have a sliding door system you will need to extent the
total distance to 18".
Second, Run 2 x 4 x 10's across from side to side using perpendicular
bracing to support from top of batter boards, allowing a 2"
space between 2 x 4 x 10's and inner batter boards. (See illustration.)
The important dimensions from one end to the other are noted
here according to which package that you have. If you have
a building with no ends your total length will be the building
length (# of arches x 24 + 5") (See Illustration)
If your building has one steel end wall and the other end
is open your total length will be the total length the building
(# of arches x 24" + 11") Note: If you have a sliding door
add 8" to step for door system to be grouted in or a graded
slope. (See illustration)
If your building has 2 steel end walls your total length will
be the total length of the building (# of arches x 24" +18")
Note: If you have sliding doors, add 8" to the step for each
side with door systems. This will allow the door system to
be grouted in on a graded slope. (See illustration)
After setting forms, pour concrete on sides first and then
the ends. You may need to thin your concrete by adding a little
water, which will allow the concrete to flow into the forms.
Pour concrete on sides shaking the concrete down to remove
any air bubbles, which will cause honeycombing or pockets
in your footer. Next pour concrete on ends up to the bottom
of the 2 x 4's that is used for the step down.
Shake well to remove air bubbles. Now take a shovel or bucket
and fill in between the 2 x 4's and inner batter boards. (See
Illustration to form step up.)
Scrape off the top of the concrete to level at the top of
the batter boards. Finish with a finish trowel and broom finish
for buildings that need to be grouted and stick finish for
buildings that are not grouted.
If you are using C-channel or industrial arch connector first
set up forming batter boards allowing 10" between them. Do
this for each side and also each end that is going to have
steel ends. Be sure to make them level and square. The outside
width dimensions of your footer for C-channel and industrial
arch connector will always be the exact width of your building
+ 5". (Foundation example)
The length of your footer will have the total length of your
building + 5". (Note: If you are using a sliding door system
you will want to form an additional step down to allow for
the sliding door to put the track on. (See Illustration)
The illustrations on this page are for reference only.
Actual dimensions are determined by blueprints and local building
codes, please reference blueprints and check with a building
inspector before forming concrete.