How Do You Build A Straight Form For Concrete?
Building a straight form for concrete is fairly simple as long as the correct techniques are used. The depth and width of the concrete placement determine the bracing and forming material required. This article will refer to a slab form, wall forms have completely different requirements. • Lay out the corner positions of the slab using stakes and string lines. A builder’s level is ideal for establishing the grade of the top of concrete, but an inexpensive line level will give decent results on short spans. • Measure diagonally on square and rectangular slabs from corner to corner, shifting parallel sides until the diagonal measurements are equal, while the lengths of the sides remain the desired widths. For simple shapes and small size slabs, this “working line” is sufficient, but for complex shapes and large critical layouts, “batter boards” should be used so that the established building lines will be available to recheck layout as forming progresses. • Place the form board starting
• Lay out the corner positions of the slab using stakes and string lines. A builder’s level is ideal for establishing the grade of the top of concrete, but an inexpensive line level will give decent results on short spans. • Measure diagonally on square and rectangular slabs from corner to corner, shifting parallel sides until the diagonal measurements are equal, while the lengths of the sides remain the desired widths. For simple shapes and small size slabs, this “working line” is sufficient, but for complex shapes and large critical layouts, “batter boards” should be used so that the established building lines will be available to recheck layout as forming progresses. • Place the form board starting at one corner alongside the string line, staking it down about 1/8 inch from the line with sharpened wood stakes. The thickness of the slab will determine the spacing of the stakes, as well as the nominal dimension of the forming lumber. As an example, a 1X4 pine board is usually stiff en
