During an average winter, Indianapolis experiences 24 days of snowfall, accumulating some 26 inches of snow. Of course, there are also exceptions to these averages, both higher and lower, along with a blizzard or two. So what happens after a snowmelt?
Let’s Examine the Snowfall
During a typical year, we’ll see snow beginning in December and running through March, with a peak in January. Of course, that first snow covers over those leaves we didn’t rake and makes everything a pristine white. Then it starts to build up.
It gets scooped and pushed off the driveway and sidewalks, drifts around the house and foundation, and builds on the roof. That’s during the first month. Over the next few months, it continues to build, often with a slight thaw happening from time to time.
How About Some Ice?
Those slight thaws lead to water-saturated ground around your home that freezes overnight. It also causes ice formation on the roof. That melting can be furthered by heat escaping from a poorly insulated attic and/or foundation.
The ice on the roof accumulates around the edges and can also freeze in the gutters and downspouts. That’s the source of those picturesque but dangerous icicles forming around your roof.
That ice buildup eventually causes ice dams. They back up any water, forming still more ice with the next freezing temperatures.
Snow Equals How Much Water?
In general, there’s one inch of water in 13 inches of snow. With a 2,800-square-foot roof, that 13 inches of snow amounts to 1,743 gallons of water. On the plus side, if it’s powdery, dry snow, perhaps the water content is only 1,000 gallons. On the negative side, heavy, wet snow can bring as much as 5,000 gallons.
That’s not the worst of it. With normal rainfall, the water starts running off the roof from the first minute. With snow, it just sits there, building up and does so over weeks and months.
Factor in your yard that’s also collecting snow, and you have literally thousands of gallons of water waiting for a thaw that can cause havoc with your foundation.
What Happens with Snowmelt?
As the sun breaks through and temperatures warm the snowmelt can start pouring over the ice that’s formed around the edges of the roof. When that happens, it falls directly on the frozen saturated soil around your foundation.
Even if the gutters and downspouts are working, the water still flows onto the frozen ground and pools on the surface. Ideally, the landscape grading will facilitate a surface flow of water away from the foundation.
Underground Water Flow
Even so, the accumulated snow on the ground will have fully saturated the soil and set up an underground flow of water back toward the basement or crawl space. Water moving off the roof will only increase this flow of water.
The underground water flow happens because of the excavation during foundation construction. When the loose soil is returned to the spaces around the new foundation, it is much more porous than the surrounding soil, which was undisturbed during this process.
That essentially creates a “bowl” around the foundation funneling water toward the basement or crawl space. You can see why this is called the clay bowl effect.
All that water accumulating around the foundation builds up hydrostatic pressure, doing its best to find any cracks or openings into your basement or crawl space. It can also create new cracks or open up old cracks through freezing and expanding.
As you can tell, the snowmelt from your lawn and roof is following gravity, seeking to find the lowest level possible. Freezing temperatures help the snow to stack up, gathering still more water to join the assault on your foundation.
Preparing for Snowmelt
The best preparation is making sure every aspect of your home is ready for snowfall and the subsequent runoff. Here is our list of actions you can take.
- Clear Rooftop Snow. The snow will naturally build up on your roof. You can use a roof rake to pull the snow down before it builds up around the edges of your roof.
- Avoid Foundation Snow Buildup. As you clear your driveway and sidewalks, make sure you’re not stacking the snow close to your home. Even better, take steps to clear the snow from a four to six-foot band around your foundation.
- Install and Maintain Gutters and Downspouts. It’s a must to keep your gutters and downspouts clear and ice-free. In preparation for winter weather, clean out the leaves and debris from the gutters, along with any obstructions in the downspouts.
- Install Downspout Extensions. Extensions to the downspouts will carry the rooftop snowmelt well away from the foundation.
- Consider Landscape Grading. The grading around your home should provide a gradual slope. This further helps move the water away from the foundation.
- Caulk and Cover Basement Windows. Basement window wells can accumulate quite a bit of snow and collect any water runoff from the roof. Provide watertight covers and caulk the windows to seal out water.
- Add Insulation. Heat escaping from the attic and around the foundation can cause early melting and ice formation. Add insulation to help prevent this and save on heating costs.
- Waterproof Your Basement or Crawl Space. Install an interior drainage system along with a sump pump to remove any water accumulation before it becomes a problem in your basement or crawl space.
- Practice Drainage System Maintenance. If you already have a sump pump, make sure it is working and that the drains are open. Watch for freezing drain lines as well.
Professional advice on preparing your home for snowmelt, from waterproofing your basement or crawl space to maintaining your drainage system, is just a phone call away. Contact your local foundation experts at Indiana Foundation Service for a free inspection and repair estimate.