By Alden Smith
In the first part of the series, we discussed requirements, preparation and codes and regulations. Here, we continue with building the forms and pouring the concrete.
Building the Forms
You have prepared the surface, insured that there were no high or low spots, and have compacted the grade. To build the forms, many contractors will lay down a string line to define the area of the pour. The driveway edges are defined first. Place a set of parallel boards on the sides of the excavation, within the defining lines. Drive stakes at the minimum of 3 feet apart along the length of the board. Insure that the boards are at least 2 inches above ground level. From the highest point of the excavation, place the straightedge across the two parallel boards, and use the level in the center of this to insure proper levelness. This should either follow the contour of the ground, or, better yet, provide a pitch for drainage to the road. Use double headed nails to attach the stakes to the form boards. Tops of stakes should be level or a little below the form board. At the ends of the drive, ¼ inch plywood will be bent and staked to form the curvature for egress. A centered stop board completes the forms. Thoroughly oil the frame boards with old motor oil to insure that they can be easily removed later. Next, reinforcement mesh should be laid in the excavation between the forms. It should be cut to size, and supported with stones or brickbats to half the depth of the grade.
Pouring The Concrete
Concrete should be poured in sections with an expansion joint to allow for expansion and contraction of the medium during changes in the weather. At the edge of the garage slab, an expansion joist is deployed. The driveway will be poured in two different ways, dependent on configuration. If building a crowned driveway, it must be poured a section at a time. Otherwise, it will be poured all at once in approximate 10 foot sections. Each section will be defined by a centered stop board. Beginning at the garage, pour the first section to the stop board. Tamp and float as needed. Screed the concrete to assure levelness. Pay special attention to edges to make straight and uniform. Allow the slab to set up. Lightly broom the surface to give a non slip surface. Cut any expansion or control joints as needed. Remove the stop board and begin the second pour, finishing off as you did the first. Continue the above process until all concrete is poured.
Curing The Concrete
Cover the new driveway with burlap and keep moist for the first few weeks. Burlap prevents any rain from marring the surface of the driveway. Remove the burlap, remove the forms, and backfill any dirt from the form process. Remember, pouring a concrete driveway is hard work. If the budget allows, have professionals do the finishing.
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I just read Alden Smith's article on how to pour a concrete driveway. As a concrete contractor for the last 20 years, I found it not only critically lacking in detail, but also erroneous in many areas. In my opinion, this article should be researched a bit more and revised with corrections.