Crumbling concrete steps not only are unsightly, but a safety hazard as well. Patching them will enhance appearance and safety all for a fraction of the cost of new stairs. Doing so is a task that most do-it-yourselfers can easily handle.
The step's edge is highly vulnerable to damage. Expansive soil, freeze-and-thaw cycles, deterioration from salt and disruptive traffic are a few of the causes of the crumbling of concrete stairs.
Before going into the patching process, we'll discuss preventive maintenance. While not all damage can be prevented, much can. Extreme temperatures can cause concrete to fail. Many people think of concrete as a hard substance that doesn't expand or contract. Not so. It expands in hot weather and shrinks in cold.
Concrete is quite porous and readily absorbs water. When temperatures drop and concrete is wet, it freezes, causing cracking, spalling or chipping. This condition can be minimized by periodically sealing the concrete with an acrylic or silicone-based concrete and masonry sealer.
These products are generally clear and will last for six months to a year depending on the climate. Inexpensive water seals don't offer the level of protection that some of the more expensive products do. Moreover, they need to be applied more frequently which can, in the long run, end up costing more money.
Concrete sealers can be applied with a brush, roller or with a pump garden sprayer. It is imperative that the concrete be clean. Give it a power washing with a pressure washer or water blaster prior to application. Rock salt used to melt snow is another cause of deterioration of concrete. Once snow is melted, rinse the area with hot water to remove the majority of the salt. A light sprinkling of sand will prevent slipping on an ice slick. The water seal also protects the concrete from salt damage.
Crumbling steps frequently result from what were once small cracks that were not tended to. Much of the damage can be prevented by caulking the cracks. The caulking allows the concrete to expand and contract, yet prevents moisture from entering the area that invariably leads to increased damage. A siliconized latex caulk is your best bet.
When patching concrete steps, the tools and materials make the difference in getting professional results.
The tools you'll need include safety goggles, a hammer, small sledgehammer, cold chisel, mixing container, shovel, garden hose, concrete finishing trowel and a wooden float. The materials needed include one-by-four or two-by-four scrap material, duplex head nails, a concrete bonding agent, ready-to-mix concrete patch material and a tarp or plastic sheeting.
Start the repair process by removing the loose and crumbling concrete with a sledgehammer and cold chisel. Undercut the edge of the step into an inverted V-shape, being certain you reach solid concrete. This will help to hold the patch in position. Be sure to use safety goggles.
Sweep up all of the debris and clean the area using the strong spray of a garden hose.
Paint the raw patch area with a concrete bonding agent. The bonding agent will help the new patch material adhere to the old cured concrete. Cut scrap pieces of one-by-four material and plywood to act as form boards. Apply a light coat of clean motor oil or form release oil on the surface of the form boards facing the concrete. This will prevent them from sticking and damaging the patch.
For a smooth patch, the form boards should be placed flush against the face of the steps. Use stakes, angled two-by-fours and bricks or other heavy objects to hold the form boards firmly in place. Duplex head nails can be used to secure the side forms to the riser board. In a mixing container a bucket for small jobs, a wheelbarrow for large ones combine concrete patch material and water. Vinyl concrete patch or polymer cement are a couple of user-friendly products that blend nicely with the old material when dry.
Mix according to directions and pack into the area with a wood float and small tamp stick. The butt end of the float works great for this. The consistency of the patch material should be loose but not runny. For a solid connection, the material should be firmly packed into the orifice. This eliminates air pockets.
Remove excess patch material with a wooden float and finish the patch to match the surrounding concrete with a metal concrete trowel. Once the material has begun to set up approximately 10 to 30 minutes cover it with a tarp or sheet or plastic. This will hold moisture in and aid in the curing process. If the material dries too fast, it might crack or not adhere securely.
Pull back the cover daily for a period of up to one week, spray the patch with a fine mist of water and replace the cover. Leave the forms in place during the curing process to reduce the chance of damage from form removal or foot traffic.
Complete the job by carefully removing the form boards, stakes and bricks.