How to: Paper Concrete Form

The paper used to make concrete forms is more like cardboard. They are usually used to contain prefabricated structural shapes like columns but forms are also made for onsite pours of columns, beams and walls. The forms are lightweight, premade and sometimes treated with a releasing agent that discourages concrete from sticking to them. And they are always filled with a "monolithic" concrete pour, which means that they are filled all at once and left until the concrete inside them dries. The concrete shape that remains is then left to cure in the air.

Releasing agent
Collars recommended by the form's manufacturer
Light lumber for braces
Concrete vibrator
Sharp knife
Shovel

Instructions

- 1
  Coat the interior of some paper forms with a releasing agent.
- 2
  Place concrete forms over reinforcing bar cages according to the building plans for your construction. Avoid damaging the interior of paper forms when placing over rebar.
- 3
  Surround paper forms with collars recommended by the manufacturer of the form. Collars are supports that exactly fit over the paper form and allow wooden or metal braces to be attached to the form.
- 4
  Brace paper forms with light lumber attached to the collars. Form braces are vertically oriented supports that attach to forms at an angle and extend to the ground. Braces are used to keep all concrete forms, not just paper forms, from moving during a pour.
- 5
  Pour concrete into the form using a pour rate specified by the formulas published by the American Concrete Institute. These formulas account for the amount of cement, rocks and water in the concrete mix and the size of the form.
- 6
  Insert a concrete vibrator vertically into column and beam forms at the start of the pour. Keep the vibrator at the bottom of the form for 15 seconds and then pull the vibrator out of the form at about one foot every four seconds. Use a vibrator that is about one-eighth the diameter of the form
- 7
  Strip the form from the concrete after 24 to 48 hours. Strip forms by making a vertical cut in the top 18 inches of the form with a sharp knife then pry the form off the concrete in a spiral using a shovel.

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