Q: I have downspouts on the north side of my house. After a few sunny days some snow melts but the spouting isn’t melted and the water overflows and drips directly over the door, which is about 10 feet from the downspout. Even if the attic were properly vented and insulated to prevent ice damming, could there still be a problem when the heat from the sun warms the roof to melt the snow but the spouting is still frozen enough to not allow the flow of water to the downspout?
There is no access to any crawl space, so what would be the best alternatives to checking the situation out?
Also, there are no visible signs of vents anyplace on the building. This is a three-unit townhouse, built in 1977, and the only place it drips is the end unit nearest the downspout, as all the water flows in that direction. There doesn’t appear to be any problem with water backing up into the unit. –Sandra R.
A: If you have snow on the roof and ice in the gutter and downspout, then when the sun melts the snow the resulting water runoff would hit the ice and potentially have no where else to go except to the drip over the edge of the gutter. This is not a true "ice dam," which occurs from snow melting from the bottom side of the snow pack on the roof, not the top side. This could be why you’re not seeing any damage inside the house.