Some home foundations use concrete forms to form the slab if:
STEP 1: If your ground is level and you can form the home foundation with lumber and pour a monolithic slab. After you dig the trenches out completely, you need to form the foundation before placing the steel. To do this you will need 2x6 (or larger) lumber for the forms and a lot of 2x4 lumber for the stakes and kickers.
STEP 2: Cut about the 2x4 kickers three or four feet long, and also cut two stakes – 16 to 24 inches long, for each kicker. Buy the form boards in long lengths – 14 feet long at least. If your floor level is high, you may need to cut an angle on the end of the kicker.
STEP 3: Lay the kickers around the perimeter, across the footing trench, spaced about every two feet. Take a little care to lay them fairly straight, perpendicular to the trench in your home foundation.
STEP 4: Using the kickers as a guide, drive two stakes in the ground, beside each kicker, until they are solid. Position the first stake beside the kicker, at least 12 inches away from the edge of the trench, and the second one beside the kicker a foot or so farther away. Use your kicker as a guide to be sure the second stake isn't too far away. The kicker will need to reach the middle of the trench, and be long enough to reach the second stake. The kicker stakes must be solid, so drive them in deep enough to be able to stand on them without affecting them.
STEP 5: When you have finished driving all the stakes, you are ready to start forming your home foundation. Pull the layout string into place and cut your form boards to length. Cut the first side form boards a little longer than the actual measurement of the side.
STEP 6: Lay the form boards beside the trench along the first wall.
STEP 7: Measure the distance from the layout string to the bottom of the footing and cut two 2x4s that length minus the width of your form board, for each form board piece. Make these stand boards a half inch to an inch longer than the actual measurement, meaning that when you place them under your form board, it will make it be a little higher than the layout string.
STEP 8: The layout string represents the outside edge of the foundation. So, your form board must go outside the string. Using a helper, hold the first form board up on its edge and place the stand boards under it. Nail a kicker to the backside of the form board, being careful to not allow it to stick up higher than the top of the form board. Drive two 16d nails thru the face of the form board into the end of the kicker.
STEP 9: Position the kicker beside two stakes, being certain that the end of the form board extends past the corner of the foundation. (the intersection of the layout strings, not the edge of the footing).
STEP 10: Using the temporary stand boards to hold the form board up, use the kicker to adjust the form board in or out until the string is laying against the face of the form board. Screw one screw from the kicker into a stake to hold the distance. (or use a nail gun) Repeat the process, moving down the length of the form board. You will need to recheck the string position many times to be sure that it lays against the form board, but is not pushed or deflected from true by the board. If you must be off in this stage, allow the string to have a slight space from the face of the board, rather than be too close and deflect it from true.
STEP 11: Continue this process for the length of this side of the house of your home foundation. Butt any additional form boards end to end, and be sure that the end of the run extends past the foundation corner a few inches.
STEP 12: Once all the form board pieces are in place, cut 24 inch boards to span the butt joints and screw them in place. Be sure that the joint scabs do not stick up higher than the form boards in your home foundation.
STEP 13: Starting in the middle of the run, use your kickers to position the form board against the string with the top edge a little above the string. Screw the kickers in place solidly. Work from the center to one end, then return to the center and work out to the other end. Go back and double check the string several times, again being sure that you are not pushing the string away from true.
STEP 14: Once you have all the kickers secure, remove the temporary stand boards from under the form boards.
STEP 15: You now have a form board length hanging in mid air. Go down the length, tapping the front kicker stakes down to bring the top edge of the form board to exactly the height of the layout string. As you progress, tap the form board toward the house if there is a gap between the face of the form board and the layout string. Again be careful not to influence the string or push it out of true.
STEP 16: Once you have the form boards positioned perfectly in your home foundation, shim between the end of any kickers and the form boards that have been gaped by tapping the form board over to the string.
STEP 17: When you have the first run perfect, place some temporary stand boards under the form board to help prevent any accidents – AND DON'T STEP ON THE FORM BOARDS!! You may be able to use the previous temporary stand boards and just tap them into the trench a little, or lean them over a little. It’s just a good idea to have some insurance in place against accidents.
STEP 18: Moving on to subsequent runs, cut your form boards to the length of the side, adding one and a half inches to the length. The final side that eventually completes the perimeter of your home foundation will be cut to the exact length without the additional inch and a half. The extra inch and a half allows you to butt the next form board to the first and fasten them together, making placing the boards easier and making a stronger corner.
A monolithic slab is a foundation in which you pour the footings and the slab at the same time. This yields a stronger overall foundation and lets you pour everything at one time. Basically you can only place a monolithic slab on relatively level ground.
After the forms are in place, you must prep the slab.Return from Home Foundation Concrete Forms to Home Building Mentor