February 2022

Does your driveway appear to be sinking or uneven? The truth is, it’s more common than you realize and can be caused by a variety of different issues. In this guide, we describe the potential causes of a sunken driveway and also address ways to repair the damage.

A sinking driveway could be due to a number of reasons:

• Poor foundations or ground preparation: A surface is only as good as the base it is laid on. Should the foundations or sub base be poorly laid, not compacted properly, have inadequate drainage or groundwork or generally weak, this may already be setting your driveway up for future problems.

• Water leaks: Water is an enemy of driveways, which is why it’s important to watch out for surface cracks, leaking pipes or garage downspouts. These weaknesses may cause water to pool on and under the surface, causing the soil or sub base to weaken and sink.

• Environmental factors: Nature may have a hand in driveway subsidence. Your home could be located on a unstable ground, such as marshland or an area experiencing volcanic or seismic activity, or an area experiencing altering water tables or gradual root growth.

• New developments: If your home is located on a newly development area, a sinking driveway may simply be because the land has not had time to settle and establish itself, or perhaps because inappropriate or inadequate materials may have been been used.

When a driveway sinks, the surface depressions may experiences water pooling, further leading to structural damage, icy patches forming, algal growth or cracks – this will decrease the functionality of the driveway, and possibly reduce the asking price of your property.

Fixing your sinking driveway

Before you commence repair work, first identify what’s causing the trouble and if there is any way of bypassing the same issues in the future. For example, if water leakage is the culprit, seek out the water entry point or weakness and correct it.

The four main approaches to fixing your sinking driveway are:

• Relay the paving or asphalt: The primary option will be too relay the paving stones or asphalt – depending on the extent of the problem, you may only need to do this on the afflicted sections or possibly the whole driveway. Though, if the issue has been identified as a base level problem, it could be in your best interests to relay the whole surface. Depending on how well you are able to extricate the sunken paving blocks, you may require new blocks as replacement.

• Level the area: Attempting to re-level the surface with an aggregate such as grit or sand could also be an option – however, it may spoil the aesthetic of your chosen surfacing material. Alternatively you can place another layer on top, such as paving stones – make sure you lay the adequate groundwork first.

• Call in the professionals: If DIY just isn’t for you, simply call a reliable specialist to ensure you receive the quality and appearance you’re seeking. A professional company will use your chosen materials to repair or relay your driveway, restoring it to full health and performance.

If you are considering repairing your sunken concrete you may be wondering what exactly is mudjacking and if there are other better methods available. Mudjacking is not new. This technique used to lift and level sunken concrete slabs has been around for over 70 years. The mudjacking process works by pumping a slurry (typically comprised of a mixture of sand, cement and/or soil) below a slab through holes at the surface. The hydraulic pressure from the mudjacking machine causes the slab to rise.

While mudjacking does work, this repair process is not without its problems. Below we explain the main issues with mudjacking that property owners need to be aware of before selecting a repair solution and why the use of polyurethane foam is now the preferred method for lifting concrete.

The Foundation

The material used in mudjacking is not waterproof and not ideal for our northern climate. As water drains below the concrete and is exposed to freeze/thaw cycles, the sand, cement and soil material is susceptible to shrinking, erosion and breakdown. This material breakdown can cause the concrete to sink again if there is not proper drainage around the area and/or the cracks and joints were not sealed to prevent water from getting below the slab.

Settling

The material pumped below the concrete (if done correctly) is going to be rock solid after 24 hours. That is a good thing however it’s also going to be extremely heavy and that’s not good.   The weight of the original concrete over a poor base is usually what caused the slab to settle in the first place and by adding additional weight over the base you’re asking for additional settling to occur.

Large Holes

In order to pump the thick material below the slab, large holes (1” – 2’ inches) need to be drilled. Along with being an eyesore, these large holes compromise the structural integrity of the concrete, which can cause cracking to occur.

Polyurethane Foam As An Alternative

In the 1980s state and federal transportation engineers started injecting high-density polyurethane below sunken roadways. This method was selected over traditional mudjacking due to polyurethanes light weight and durability.

Also, polyurethane cures in only 15 minutes verses 24 hours with mudjacking – a critical benefit when dealing with busy roadways. For the next twenty years the polyurethane injection or PolyLifting method was patented and installed by only one company, mostly on highways and large projects.

In the early 2000s the polyurethane injection process patent expired. Now the material and process is available to all contractors to use. This has caused it to be economically feasible to use on residential projects such as driveway, walkways, garage floors and patios.

PolyLifting is now the industries preferred method for raising and leveling sunken concrete due to its longevity, small injection holes and quick return to service.  Compared to mudjacking, the use of polyurethane is considered a long-term repair option.  Visit our facebook page for reviews from our customers.