Concrete tube forms, also called "tubular column forms," are made of cardboard-like fibre and coated with a release agent that allows for quick, clean removal from hardened concrete. Aside from the effort required to dig your trench, installing and aligning a concrete tube form is easy and substantially faster than building wooden formwork.
Dig a hole a few inches larger than the diameter of the concrete tube form that you are using. Dig the hole to the desired depth of the concrete pillar.
Place a level across the top of the concrete tube form. Adjust the tube form's position until the level's bubble rests between the centre indicator lines; this position indicates the tube form is level.
Shovel dirt into the area between the tube form and sides of the hole. Distribute the dirt evenly around the tube; be careful to avoid jostling the levelled tube form. Completely fill the hole surrounding the tube form.
Fill a wheelbarrow with enough water for the amount of concrete you are using; consult your concrete mix package for detailed measurements. Open the concrete mix and slowly incorporate the dry mix with the water. To avoid clumping, do not dump the mix directly on top of the water, but pile it on the elevated portion of the wheelbarrow's bucket. Mix the dry and wet ingredients with a shovel.
Scoop the mixed concrete into the tube form with a bucket or shovel. While filling the form, occasionally plunge a short pole into the concrete to help the mixture settle and to remove air pockets. Fill the form until concrete slightly overflows. Strike off excess concrete and level the finished surface by drawing a screed across the top of the form.
A straight 2-by-4 piece of lumber serves as an inexpensive screeding tool. If your concrete tube form stands more than a couple feet above the ground, you must brace it with wooden forms. If your project requires a steel reinforcement bar, install it after positioning the form in the hole.
Tips and warnings
- A straight 2-by-4 piece of lumber serves as an inexpensive screeding tool.
- If your concrete tube form stands more than a couple feet above the ground, you must brace it with wooden forms.
- If your project requires a steel reinforcement bar, install it after positioning the form in the hole.