Why is my roof leaking in Winter?

It’s winter (not technically, but it’s December).  Typically from December through February, depending on where you live of course, there’s not a lot of rain coming down.  Snow, sleet, and ice take over during the cold months, so why would an otherwise functional roof start to leak in the middle of winter?

The answer is Ice damming.  If you already know what this is and how it works, you may move on to checking your ebay items or to your online Christmas shopping, but if you don’t know what an ice dam is, please read on.  I want to just briefly explain what it is.

An ice dam (or ice jam) occurs when water builds up behind a blockage of ice.

Illustration of an Ice Dam

When snow on a roof melts, moves down the slope, and re-freezes further down the roof, it could potentially create an obstruction preventing additional water from passing.  This water may then be forced uphill and underneath shingles where it could find passage into the structure.  Roofing is only designed to keep out water that’s travelling downward with gravity.

There’s nothing we can do about these crazy weather cycles.  What we can do, as I wrote about earlier this week, is make sure an excessively warm attic isn’t what is melting that snow.  If it is cold outside, and warm in the attic, the snow can melt and the water may then re-freeze at the edge of the roof where there is no attic under the roof.  Now you have a huge ice barrier all the way around the edge of the roof, playing bully to the poor water that just wants to get to the gutter.

Nobody likes a bully.  Make sure your attic is properly insulated.

  • Dave Combs

    Great post!

  • Gabrielle Jeromy

    So next time you check your roof during the winter, see if there are ice dam formations on the roof and the gutters. The best way to remove them is to use a shovel and a pike. Be careful though. Ice is slippery and very dangerous. 

  • plumbing

    I have been also wondering how does it happen. Know i why i am experiencing roof leaks even in winter.

Why Choose HomeScan?

HomeScan Inspection provides high quality residential property inspections for buyers, sellers, lenders and investors. We specialize in single-family homes, townhouses, condominiums and multi-family units in Northwest Indiana.

We are certified, insured, and licensed to perform home inspections in the state of Indiana, and will provide you with a detailed inspection and report of a homes condition, including all of its major structures and systems.

Indiana Home Inspection Schedule