Why does my Roof leak during the winter?

Oh the Holidays. The Carols, the Lights The eggnog and Cheer.  The dark circles that suddenly appear, on your ceiling. It hasn’t rained for a while and not to much snow. So what are these Phantom circles you ask? Good Question.

Here are the most common causes of the winter question of “why does my roof leak in winter?”. These are in no particular order.

1.Roof Vents designed without a filter can let a fine wind driven snow to blow in. This piles up in the attic while it remains cold, but after it warms up outside to above freezing the snow begins to melt and can start to drip and stain the ceiling. The snow once melted will go away and it may be several years before these conditions occur again. Simple solution, the hardware stores sell a commercial filter that will come in a roll, Usually Blue and about 1″ thick. This can be cut with a scissors and friction fit into bottom of the vent or if you can around the up right portion of the vent. The filter blocks the snow but allows the air to flow freely.

Stains around vent show where water has been leaking in.

2. Condensation on pipes that vent through the attic. Heating or furnace pipes are warm and carry warm moist air right up the pipe. The warm air rises and collects on the cap and then runs back sometimes into the double wall pipe. The water is trapped within the double wall until it finds a escape. Most usually at a bend  in the pipe or elbow. The water then drips into attic and onto the ceiling. One solution My heating and air friend use’s is , Remove the cap and seal the top of the double wall pipe with a high heat silicone or Urethane sealant then re-install the cap. The sealant keeps the water from getting into the pipe, simple solution.

Why does my roof leak

3. Are your bath fan vents Insulated and through
the roof? Same as number 1. the bath vent transfers warm moist heated air into
the attic. This can cause several problems. Too much moisture in the attic can
cause the roof sheeting to swell and buckle, this is an expensive fix. Moist
attic combined with poor ventilation can cause mold build up. This can be a
health problem as well. Simple solution, make sure vents extend through the
roof and have a backflow flap on the vent. The pipe should be insulated to keep
from condensation. Make sure the attic is properly
ventilated.

Non insulated bath vent pipe.

New insulated vent pipe.

Ice Dams are formed when the temperature outside, warms above freezing during the day and melts snow and re-freezes overnight. This occurs on the cool part of the eave or the non heated surface of the roof. Then this cycle of thaw and re-freeze continues until the ice forms so thick that it causes water to dam and run backward underneath shingles.