How to Remove and Replace a Small Concrete Entry Pad

Reinforcement Isn’t Required, But…

For a small concrete pad-less than 40 sq. ft.- you don’t normally have to bother installing steel reinforcing bar (rebar). However, doing so adds strength and crack resistance to the pad if you lay out the rebar in a grid pattern 2 ft. on center.

You’ll find 10-ft. lengths of rebar for about $5 each at home centers, and you can cut them to size with a hacksaw or an angle grinder. You’ll also need tie wires and a wire-twisting tool to connect the pieces of rebar in a grid pattern. Get more information about reinforcing concrete with rebar.

Four Things to Know About Concrete

1. Too much water weakens concrete: If you mix too much water with concrete, cement crystals form farther apart, leaving concrete weak and porous. That can cause trouble later as pores and pockets fill with water, freeze and break up the concrete’s surface. With the right amount of water, cement crystals grow tightly together and interweave to form strong, watertight concrete.
2. Floating too soon leads to trouble: As concrete sets, water rises to the surface. Left alone, this ‘bleed water’ is reabsorbed into the concrete. But if you float the watery surface, you’ll force the aggregate and cement down, leaving a watery mix of sand and too little cement on top. Wait for the bleed to disappear before floating. Also, don’t overwork it. Too much floating (or troweling) will lead to a less durable surface.
3. The longer it stays damp, the better: Concrete doesn’t harden because it’s drying; it hardens because it’s wet. The longer concrete stays damp, the harder and stronger it gets. The hardening or ‘curing’ process can continue for weeks if the concrete dries slowly. Covering it with a sheet of plastic also slows the curing process.
4. It can burn your skin: Some people get concrete on their skin and don’t have any problems, but others are more sensitive to it. Until they cure, all cement-based products have the potential to leave minor burns on your skin. Play it safe and wear a long-sleeved shirt, long pants, boots and waterproof gloves when working with concrete.

Order the Right Concrete Mix

Bagged concrete vs. ready-mix:

Most small pads require less than one yard-27 cu. ft.-of concrete. You can buy several bags at the home center, which you’ll have to lug home, mix with water and pour yourself. It’s a lot of work, but it might make more sense financially for a small pad at the bottom of your deck stairs. For bigger pads, have ‘ready-mix’ concrete delivered. It comes mixed with water and the delivery guy will pour it right into your forms. Prices vary by region, but expect to pay about $300 for 1 yard. Order it a few days ahead. If rain threatens, you can usually cancel up to two hours before delivery.

Order the right concrete mix:

• Plan to pour a pad at least 4 in. thick and calculate the right volume. Concrete is ordered in cubic yards. Many suppliers have calculators on their website, but it’s fairly easy to figure out how much you need. First figure out the cubic footage, then convert to yards by dividing by 27. Here’s how: Multiply the length of your pad by the width by the depth (4 in. = . 33 ft.) and divide the total by 27. Order a little bit more than you need. A good rule of thumb is to order an extra 5 percent rounded up to the next 1/4 yd. to handle spillage and uneven bases.
• Order from the nearest supplier. Get fresh concrete mixed near the site, not across town by some company with a lower price.
• Ask for 5 percent ‘air entrainment’ in the mix. Suppliers add a chemical that traps microscopic air bubbles to help the concrete accommodate the expansion and shrinkage caused by climatic changes such as freezing.
• Get the right strength. Tell the dispatcher you’re pouring a pad and they’ll recommend the correct ‘bag mix’ (ratio of cement to aggregate and sand). In cold climates, they’ll probably suggest at least a 3,000-lb. mix. That means the concrete can support a 3,000-lb. load per square inch without failing.
• Have your checkbook ready. You’ll have to pay after the concrete’s unloaded.

The truck arrives with the concrete premixed with the correct water content. But the driver may send a little concrete down the chute and ask if you’d like more water added. Unless the mix is too dry to get down the chute, forget it. It should be thick-not runny. Wetter mud may be easier to place (fill the forms), but the wetter the mix, the weaker the concrete.