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Thu, Aug. 22

Melted snow can find its way into your foundation

This has been the snowiest winter in Prescott in a long time. We had a heavy snowfall at the end of December, followed by unusually cold weather. There was still snow and ice in the shade six weeks later in February. Then we had another heavy snowfall this past weekend.

One result of this snow was my realization that a lot of Prescott drivers should not be allowed to drive on snow. Some should not be allowed to drive at all, for that matter. I turned 16 in November in Wisconsin. There was a foot of fresh snow on the ground when I took my driver's test, and I didn't drive on dry pavement for five months after getting my license. We lived in the Rocky Mountains before we moved here. So I'm used to snow. I went out the morning after the December snowfall, and was amazed to find cars abandoned all over the place - at stop signs, in the middle of busy streets, across/blocking side streets and driveways - everywhere. Why people would walk away and leave their $40,000 car in the middle of a street is beyond my understanding.

Another result of this snow and cold weather was numerous calls from homeowners who have water entering their crawlspaces (the area under a home). Some callers have owned their home many years and never had water in their crawlspace before.

This is not unusual with this weather. Rain will quickly drain away from a home, assuming the site drainage around the home is good (i.e. the ground slopes away from the home). If you think about it, even after the heaviest monsoon, the roads are dry a short time after the rain stops. Mostly. Except for puddles in potholes and low areas, of which Prescott has many. The same is true around a home. Most homes have gutters to control the roof water and, shortly after a heavy rain, the soil around a home is relatively dry.

But snow staying on the ground for weeks will slowly melt and completely saturate the soil around a home. And the cold weather may cause ice in subsurface drains or on the surface where water would normally drain, causing more moisture to remain around the home.

Now remember that no masonry product is completely waterproof. Moisture will seep through concrete, block walls, bricks, stucco, and any masonry product. So with super saturated soil next to a home for several weeks, it becomes more likely that some of the moisture will get through concrete or block stem walls and find its way into a crawlspace.

The good news is minor and/or occasional moisture in a crawlspace is seldom a structural concern. Constant water or moisture in a crawlspace is a concern, of course. Constant humidity can cause rot or fungus on wood and corrosion or rust on metal (nails, framing straps, etc.). Humidity can also cause condensation on water lines, air conditioner refrigerant lines and even on insulation.

But if you have some water in your crawlspace after unusual weather you should not be too concerned. My advice is to make sure all your crawlspace vents are open and not obstructed. Check for dirty screens or insulation in the crawlspace obstructing the airflow through the vents. If you're really concerned you can put a fan near the crawlspace access blowing in or out. Be careful with electrical appliances on wet soil. Put the fan on a piece of wood or blocks, and don't run it constantly. Just turn it on during the day when you're home. If you don't have an outlet in the crawlspace, you can run an exterior rated extension cord to an exterior outlet (which should be GFCI protected) and turn the fan on and off by plugging and unplugging the extension cord.

Water entering a crawlspace under a manufactured home can be a larger concern. Most manufactured homes in our area are supported on metal posts that are supported on concrete blocks or pads. If the soil in a crawlspace under a manufactured home gets and stays very wet, the pads can settle, allowing the posts to settle and possibly loosen, which then can allow the home to settle. You should have all the posts under a manufactured home checked occasionally and secured/tightened if needed. If you haven't had this done in a while (or never), after this winter would be a great time to have it done.

I've also had quite a few calls about roof leaks, and again people are having leaks where they've never had one before. This is often caused by ice in the gutters and downspouts, causing ice to back up onto the roof. These are called ice dams and are common problems in some areas of the country. Ice dams usually form near the gutters, but can also form in other cold areas, such as a valley or where a patio cover meets the home roof. The snow above the dam starts to melt. Water runs down the roof under the snow until it hits the cold area and freezes. This continues until you have a dam that causes water to pond on the roof above the dam. Slope roofs are designed to shed water downhill, not to hold water. Water ponding on a shingle roof can get under the shingles or flashings and cause leaks. The remedy is to shovel/sweep the snow off the roof, and make some paths through the ice for water to drain. I can't recommend this, because it is very dangerous to work on a snow- or ice-covered roof. It's much better to pay a licensed contractor or that kid in the neighborhood you don't like too much to do this.

Randy West owns Professional Building Consultants in Prescott. He is a state-certified home inspector and has performed almost 6,000 home inspections in the Prescott area. West is past president of the Arizona chapter of the American Society of Home Inspectors, and currently serves on the Home Inspector Rules and Standards Committee for the Arizona Board of Technical Registration. Contact him at

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