Happy Spring Northeast Wisconsin!
As the last of the winter snow melts away, you may be noticing new sunken concrete or areas that have developed cracks. This is very common in cold weather areas like here in Wisconsin. Despite being extremely hard and durable concrete is still a porous material. During a warm winter day the sun will come out and snow will begin to melt. The melted snow will soak into the concrete and as the sun goes down the temperature outside will go down causing the water to freeze. This process will go on and on throughout winter. This is known as the freeze-thaw cycle. When water freezes it expands and it can actually begin to split concrete or push panels apart leaving wide gaps between the slabs.
Melted snow can also trickle down below the concrete and as temperatures fall the water will freeze and expand pushing up on the concrete and pushing down on the soil beneath. This can result in a permanently heaved slab or because the soil has been disturbed, future settlement. Trip hazards can become present or concrete will become improperly pitched.
Freeze-thaw is an equal opportunity troublemaker. This constant freezing and thawing can affect old concrete that has been stable for many years and it can damage newer poured concrete. The freeze-thaw cycle can also cause problems on foundation walls do to improperly pitched patios, walkways, and driveways.
So, what can a person do to help combat the freeze-thaw cycle?
Unfortunately there is very little if anything that can be done to correct this issue during the winter months. That is why it is important to identify concrete problems in the spring and summer before they get worse. Check your downspouts and make sure they run away from the concrete. Snow melt from rooftops can cause a lot of ice buildup on driveways and walkways. Identify ice dams in gutters during the winter and install an ice dam melting system before the next winter so that the water is flowing where it is supposed to.
Sealing cracks and joints with one of the many crack and joint sealers hardware stores offer can help keep water out. Most often these products come in a pourable form or a caulk tube. A person may also want to look into applying a concrete sealer which can be sprayed or rolled on.
It is recommended to occasionally check the pitch of your concrete around your home to make sure that it is indeed sloped away from the foundation of your home. This can be done with a simple level from the hardware store. If the concrete is pitched towards the foundation you have two options to correct it. You can have the concrete replaced which can be expensive, time consuming, and disruptive. Your other option is to have the concrete lifted.
Most people are familiar with the process of pouring new concrete but many people are unfamiliar with concrete lifting. Concrete lifting is much more affordable than replacement, usually half the cost or better and the process can be completed in less than one day with very little disruption to landscaping and parking situations. Concrete lifting work is usually contracted out to a professional lifting company who will either use traditional mudjacking methods or the ever growing polyurethane foam lifting process. A person who specializes in mudjacking will drill a series of holes through the slab usually ranging 1” to 1 ½” and pump a grout slurry underneath the slab filling spaces and forcing the concrete back into position using pressure. Polyurethane foam lifting is where a company will drill 5/8” holes through the concrete and inject a 2-part foam underneath the concrete. The foam is injected into each hole and starts to expand gradually lifting the concrete into position. DOT officials and engineers prefer the foam lifting method because of its durability and light weight characteristics. Most homeowners prefer the polyurethane option as well because of its small injection holes which when patched are nearly invisible.
Along with the pitch of your concrete you may also want to check for gaps between concrete and foundation walls. A widening gap is usually an indicator of sliding concrete and can be an indicator of poor soil conditions. A permanent fix for poor soil conditions is nearly impossible but polyurethane injection can help stabilize soil near the surface due to its soaking nature. In some situations polyurethane can be injected deep into the soil 5-10 feet below the concrete giving the slab a much stronger base.
It is important to identify concrete problems before they get worse. These problems will not fix themselves but with early prevention and routine maintenance concrete can last a very long time. Keeping your concrete graded away from your home will help prevent the freeze-thaw cycle from damaging basement walls. Sealing joints and cracks will help prevent concrete from cracking and widening as well as keeping concrete even. Snow plows, snow blowers, and shovels can chip and break