Why is my patio cracked?
The number one issue with outdoor patios is settling or sinking. When a patio settles, it typically does so in various sections and unevenly, which leads to unstable, wobbly surfaces. Cracks will also form as the weight of the concrete surface will no longer be supported evenly underneath. Leaving the patio or walkway in this condition will lead to stubbed toes, leaning furniture, and an overall undesirable place (especially with those unsightly cracks!).
How do I fix it?
So, what causes a patio to settle in the first place? Prior to the concrete being installed, the ground is prepared by compacting the earth underneath with heavy machinery. In most cases, this compacted surface will either be gravel or at least covered with a layer of gravel. These steps are taken to prevent the ground from settling under the weight of the patio installed above. However, sometimes settlement is inevitable due to weather conditions, namely rain water washing away the soil underneath. Also, sometimes the compacting is not done correctly or thoroughly enough.
Option 1: Replace the whole thing
The first way most homeowners think of to address their settling patio is to simply replace it. Seems simple enough, right?
But this method is not so simple. Replacing the entire patio will first require you to remove any furniture you may have on the surface, as well as any plants or landscaping which may be along the borders. Then you’re in for lots of labor, new materials, and foot traffic through your property. Even though it seems like the most obvious choice, replacing the whole patio is the most expensive and time consuming option on the table. So what else can you do?
Option 2: Resurface the top
If replacing the patio doesn’t sound like your cup of tea, resurfacing it might sound like a better option. However, resurfacing the patio’s top only hides the real issue. While cracks and furrows may now be out of sight, the initial problem of sinking and settling has left voids under the patio, and these holes will still exist. Severe voids will cause the patio slabs to rock from side to side, causing an annoying, and potentially dangerous, situation. Also, should the edge of your resurfaced patio be a part of a step, this step will now be higher, perhaps not meeting local codes and posing a hazard.
Option 3: Mudjacking
Mudjacking utilizes a mortar-based mixture which is injected into holes and cracks in the patio slab and pumped underneath the surface. The mixture fills all the voids and has enough force to raise uneven slabs to meet their neighbor, closing any cracks or holes. It then hardens, and prevents any further rocking or movement from occurring.
As mudjacking involves a mortar mix material, it does require a bit of labor and heavy material—so it’s not something you’d want to DIY. Mudjacking repairs may also be subject to erosion, as the material used is mortar based. The final, solid product underneath is also somewhat heavy, and its weight sometimes exacerbates the settling problem, leading to even more sinking in the future.
Option 3: Polymer slab lifting
The most recent advancement in patio repair is polymer slab lifting, which serves as an alternative to mudjacking that offers a lighter material and fewer followup problems. Similar to mudjacking, the polymer material (usually polyurethane) is injected into holes and cracks in the patio’s slabs, and then pumped underneath the surface of the patio, filling all voids and binding with the soil. As the material solidifies, it expands at a rapid rate, and so lifts the concrete surface to where it needs to be.
Unlike mortar mixtures, the material used in polymer slab lifting is surprisingly light, yet equally strong. The cleanup is also quick, as there is no excess, muddy material to have to wash away or clean with water. Once all the lifting is complete, all that’s left to do is a simple process of sealing cracks and adding the finishing touches to the patio’s newly filled and leveled surface.
Keep in mind, for patios composed of numerous smaller stones or pavers, mudjacking and polymer slab lifting will not always be applicable, as it is not possible to lift such small pieces uniformly. Different issues will call for different solutions, and so it is always advisable to call a local professional for large patios or walkways which may be facing settlement issues. Quotes should generally be free of charge, and you’ll then have a good idea of the time frame and cost involved for getting your space back into tip-top shape.