Slab Foundation

2.) Refer to these illustrations for how to setup a batter board to level this type of foundation. Local codes will vary. Some areas will require a deeper footing due to frost lines. For those, we will add a section for basements and crawl space later. You will find these type foundations more in the southern regions where there are very little to no frost line.

4.) Start at the string and install the first form board using the string as a height gauge.
Tip: strings tend to sag in the center, allowing for this will help make your concrete strait.
Fasten with #10 duplex head nails. If more than one row of forms are required, stagger each row for more strength. Install all forms and secure to each stake and at the corners. It may be necessary to rip the bottom form for a snug fit to the ground.

5.) Refer to these illustrations to get an idea of the many concrete slab configurations. Dig your beams according to your plan and the specifications of your local codes. Any plumbing or electrical needing to be installed under the slab should be done after beams are dug.

7.) Slab foundation require a vapor barrier to be installed under the concrete. Use a suitable 6 mill plastic sheathing.

9.) Using 20' lengths, bend a piece of #5 rebar about 4' from the end at a 90 degree angle. Set this piece in a corner and lay between the outside rebar stakes and the form, attach it to the steaks with wire ties about 3" off the bottom of the trench. Bend another #5 rebar at 4' and install in the same corner directly above the first but because the ends of the rebar should be staggered and not break one over the other, install with the 4' section facing the opposite direction and at 3" from the top, 4" if there is a brick ledge.

10.) Bend two more pieces, this time at 8', and install at the same height as the first two bars accept these are installed on the inner stakes. Be careful not to break the ends one over the other. Install rebar around the perimeter overlapping bars a minimum of 40 diameters, or 25" for #5 (5/8") rebar. Steel should be within 3" of the bottom and top. If rows are farther than 20" apart install another inside and outside row of #5 steel in the center. Any brick ledge needed may be installed now.

12.) On areas where the form is 18" or more above the ground, following this example, measure for a 2x4 brace to lay directly on the ground between this new stake and the form stake. Next, measure for a 2x4 to set on top of the first brace and extend to the top of the same form stake. Nail securely with #16 nails.

14.) A pump truck is the best tool for pouring large slabs. Smaller ones can be easily poured with just a truck. If access is not possible for a truck, several wheel borrows and a lot of help is an option. Other options include machines such as concrete buggies or a tractors with a bucket. However you decide to do it, dump some concrete near the center between your forms about 4' from the end. Using rakes or tools called comealongs, move the concrete till it is evenly distributed throughout from one form to the other. Use a long 2x4 or 2x6 called a screed and drag across the top of the forms to make the concrete even with the top. Pour more concrete as needed and push into the low areas or drag concrete out of the high areas as you drag the screed. After pouring an area you may no longer need the center form, so pull it out of the concrete as you go. For example, if your 1x4 form is in 12' lengths, pour about 13 to 14' all the way across the slab, then pull up that 12' section of form. You may also want to toss some concrete into the divot left by the form while you can still reach it.

15.) When you reach the end of the pour, use a tool called a bull float, which is a large adjustable metal trowel about 3 to 4 feet long with a multi sectional handle. Assemble the float and starting back at the beginning of the pour.

16.) Run the float back and forth in one area till all the pits have disappeared. Then move down a few feet and start again. Have someone following behind you and install the foundation bolts. Locate bolts 18" from the corners and every 6' around perimeter. Set bolts back from form or brick ledge 1-3/4" for 2x4 walls or 2-3/4" for 2x6 walls. Do about 8' on each side of the foundation at a time with the float so concrete doesn't get away from you. Do this till you reach the end of the pour. Water can be sprinkled on the surface if necessary to help remove the pits. Once the surface has all the pits and imperfections filled by the bull float your ready to move on.