Per square foot, concrete is one of the more affordable construction materials, in addition to being structurally sound. The cost to pour a concrete pad depends greatly on whether you intend to do the work yourself or hire a contractor. Pad size is also a factor because ready-mix concrete sells by the cubic yard. Despite the cost benefit of doing it yourself, if you are not familiar with the pouring process, it’s usually better to hire a contractor, or at least hire a helper who has concrete-pouring experience.
With a shovel and a strong back, you can dig out the soil necessary to pour a small concrete pad. If you’re looking at a pad that’s larger than you can comfortably dig, you can rent a skid steer from a construction rental store for around $150 to $300 per day. The most expensive option is hiring an excavation contractor to dig it for roughly double the cost of renting the skid steer.
Forming the Pour
Two-by-four dimensional lumber sells for around $3 per 8-foot board, as of the time of publication, but lumber prices fluctuate frequently and can be different today than they were last week. Two-by-fours are standard for building the forms that will retain the wet concrete. Purchase enough to frame around the perimeter, and get enough stakes to secure the forms every 2 feet. A bundle of a dozen 1-by-2 stakes typically sells for around $3.50. A box of 50 2-inch wood screws will set you back approximately another $5 to $6.
A typical 4-inch thick concrete pad requires steel reinforcement. For most pads, 1/2-inch rebar bars, spaced 2 feet apart in a cross-grid pattern, provide adequate reinforcement. A 20-foot bar sells ordinarily for about $7.50. The best way to purchase the bars is to measure the inside diameter of the pad, figure how many bars you need, and ask the supplier to cut them to length. Use plastic rebar chairs beneath the bars to center the bars horizontally in the forms. Rebar chairs cost about $3.50 for a box of 20, as of the date of publication, which is enough to support the rebar in a 9-by-9-foot pad. Rebar ties that twist around the bars where they intersect will add about another $3.00 to the reinforcement ticket.
Fill sand, spread to a depth of at least 1 inch, is recommended for stabilizing the base beneath the concrete pad. Sand prices vary depending on whether you haul the sand yourself from a local lumberyard or if a sand-and-gravel company delivers it. About 1/4 cubic yard is enough to fill the bottom of a 9-by-9-foot pour to a depth of 1 inch. If you haul it yourself, you might pay $30 to $60, but it can run as much as $200 if you have it delivered.
For a 9-by-9-foot pad, 4 inches thick, one yard of concrete is necessary. Online calculators are available if you’re figuring an irregular size pad. In addition to the cubic yard cost, some delivery companies also have minimum purchase requirements. A cubic yard of concrete commonly runs between $80 and $165, and it’s standard to order a quarter of a yard extra in case you run short. For example, if you need 2 cubic yards to pour the pad, order 2 1/4 yards. If the pad is in a spot where a concrete truck cannot back up and dump the mix, you can order a pump truck, which can add another $300, or more, to the cost.
Tools and Supplies
You can rent most of the concrete tools needed to pour a pad from a construction rental store for a fraction of the cost to buy them. Concrete tools, including a bull float, hand trowels, a stinger vibrator, concrete broom and screed often rent as a set for between $35 and $75 dollars per day. A power trowel, which is necessary if the pour is larger than 12 feet by 12 feet, adds another $40 to $60 to the rental charge.
The cost to pour a concrete pad takes a big jump if you hire the pros, who charge per hour, per worker. If forming and pouring your pad takes three workers two days to complete at a cost of $30 per worker hour, it could add around $1,400 to your bill. That’s not counting concrete, reinforcement, excavation and fill sand costs. You can definitely save by doing it yourself, but wet concrete, especially on a hot dry day, can start to set within 30 minutes. Unless you know exactly what to do, you could end up with a hardened concrete mess that has to be broken out and re-poured.
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