How to Lay a Concrete Pad
A basic concrete slab can be used for a patio, entryway or a surface for an HVAC unit to sit upon.
Plot out the course of the path using stakes and strings. Mark with paint. Excavate the path to a depth of 8”, removing all grass, roots and debris. Tamp down the soil to form a flat base. Pour gravel to a depth of 4” and tamp it down to a level surface.
Use 1" x 4" x 4’ boards to create forms for the sides of the walkway. Drive wooden stakes along path at 4' intervals, placing them just outside the planned pathway. Attach 1" x 4" x 4’ boards to the inside of the stakes with screws to create the form for the concrete. Make sure all form boards are plumb and level.
It is imperative that the tops of the stakes are lower than the form sides so they don't interfere in the smoothing process later. After the forms are built, spray them lightly with water before filling with concrete.
Prepare pre-mixed concrete according to manufacturer’s instructions. Working from the walkway’s lowest point to its highest, begin pouring concrete into the form. Roughly level the concrete with the back of a garden rake as soon as you finish pouring.
Before the concrete gets too hard, smooth and level the concrete by sliding a 2” x 4” board back and forth across the tops of the forms (Image 1). This process is known as screeding. Use a concrete float to further smooth out the surface of the concrete (Image 2). For best results, hold the float at a slight angle.
After the concrete has set for an hour or so, run an edging trowel along the inside of the forms to separate the concrete and create a finished edge (Image 1). At 4' intervals, lay a straight board across the forms and use a groove trowel to create expansion joints across the concrete walkway (Image 2). These joints allow the concrete to expand and contract and thus help eliminate cracking.
Before the concrete fully sets, lightly drag a broom across the surface to add a non-slip texture. Covering the concrete with plastic as it cures will help prevent cracking. After 48 hours, remove the plastic and the wooden forms.