• Forms for a slab are perimeter constraints keeping the cement in place during the curing process. Forms give the slab its shape.

• Select straight lumber with the width being 3" wider than the thickness of the slab.

• Begin nailing the forms at one corner of the site using the markers already in place as a reference point.

• If your board are not long enough to reach from one marker to the other, then join two together end for end with a scrap piece of board nailed on both ends as support. Be sure to use duplex nails as you will have to remove them carefully at a later time. Make sure the scrap lumber is nailed to the outside of the forms so as not to leave an imprint of it on the slab.

• It is very important that all corners of the forms are square. This is accomplished in the same manner as squaring the perimeter stakes, using equal diagonal measurements from each corner.

  

• As can be seen in the image above, the sides must be kept straight by with 2x4 supports throughout, to prevent bowing.

Spread and tamp a 3" layer of granular fill. Measure down from a string stretched across the forms. Slope the fill down along the edges to create a thickened edge of concrete.

Next lay a moisture barrier for the bottom of the slab.

• This done by spreading 6 mil plastic sheeting over the gravel covering the entire area inside the forms. Make sure to overlap the plastic sheets.

• Lay a grid of rebar spaced 4' appart onto the plastic accross the entire of the length of the slab.

• Now intersecting the existing rebar at 90* lay rebar again 4' appart accross the entire width of the slab.

• Place a brick under each point of intersection and at the ends of each length of rebar.

• Connect intersections with tie wire to keep rebar in place

• Divide the slab down the middle with a 2x4 nailed to 1x3 stakes. Align the top edge with a taut string.