Wet conditions around your foundation and your hardscapes can lead to heaving over the winter.
There certainly hasn’t been a shortage of rain this fall. This should prove to be beneficial for most of the plants in your gardens. Plants need an adequate supply of water in the fall so that they aren’t susceptible to desiccation (drying out) in the winter winds.
On the other hand, the last place we want water is near the foundation of your house, under walkways or patios, and behind retaining walls. Water near your house foundation is mainly a concern in areas with clay subsoils such as Newmarket and Keswick. In these areas, as the frost penetrates into the ground, the wet clay freezes, expands and grips on to the foundation walls. This often leads to upward heaving of the garage foundation and a zig-zag of cracks through the brick work where the garage and house join.
In walkway areas, freezing can cause the ground to heave over the winter. In the spring, the ground often settles in unpredictable ways causing the need for the interlock to be lifted and relayed. Other surfaces such as stamped concrete may need to be completely redone if winter heaving is too extensive.
Retaining walls are also very susceptible to wet conditions before winter. As water in the soil freezes, it has sufficient strength to push any retaining wall forward by at least a few inches. This forward movement, over time, can eventually cause any retaining wall to fail.
So with all these impacts that wet fall conditions can have, there must be something we can do to prevent it all.
To protect your house (likely your biggest investment) you need to direct water away from it wherever possible. Downspouts that drain water off the roof should empty at least 10 feet away from the foundation. This can be accomplished easily by piping the water (in solid ABS or PVC) underground so that it empties in the lawn or garden. All surfaces around the perimeter of the house should have at least 2 percent slope (1/4 inch of slope for every foot) to move surface water away.
To protect patio areas from heaving, the surfaces should have sufficient slope to move water away (2%). To limit the water infiltrating through the surface and into the base material, polymeric sand can be used. It almost eliminates water infiltration for the first few hours of rain keeping the base material nice and dry.
To protect against heaving, we at RHPL use a cementicious base material called Ultrabase underneath all our interlock and steps. The Ultrabase resists heaving and settling, eliminating the chance of having small problem areas that need to be repaired). To protect retaining walls from being overturned by frost heave we need to remove excess water that can accumulate behind the wall. This is done by using clear gravel and a perforated plastic pipe to drain water and increase air flow. Water is able to drain through the front of the wall and through the pipe, leaving the dry gravel which will not heave when frozen.
The effects of frost heave can be significant and quite devastating, but by dealing with all the wet conditions that fall brings, we can prevent any damage from occurring, so that the spring isn’t accompanied with nasty surprises.