Icicles on a gutter make a pretty winter picture, but they are also a message. They mean there was water in that gutter that could not get out, and for the rest of the year that is exactly the same problem, just less visible.
What it tells you
The gutter could not empty. A blockage at the outlet or in the pipe, or too little fall. Water that should have drained away was still there when the frost came. See
an overflowing gutter.
The drain was already blocked. If there is ice in the pipe, the blockage usually formed earlier. See
a blocked downpipe.
Heat is escaping through the roof. With a lot of ice and large icicles: snow on the roof melts from the heat inside, runs down to the cold roof edge and freezes there again. That is an insulation signal.
The gutter sags. A gutter that dips in one spot holds water there, and that is exactly where the ice is.
“A roof that loses its snow quickly is losing heat. At the neighbours’ house that is still white, the heat is staying inside.”
Fouad, owner of Astrodak Service
The insulation signal in the snow
This is one of the most honest insulation tests there is, and it costs nothing. After a snowfall, look at the roofs in your street. A roof that is the first to lose its snow while the neighbours are still white is losing more heat through the roof surface.
On an insulated roof the snow stays longer, because little heat gets through. If the snow on your roof melts quickly and thick ridges of ice form at the eaves, that is a sign that insulation is missing or that air is getting past the insulation. See
what roof insulation gives you.
Little ice
gutter drained
drainage working
Lots of ice and icicles
water stood still
and heat loss
Have it checked before it becomes a job
Most of the damage I repair was still a small fix a year earlier. Have your roof checked with no obligation and you will know exactly where you stand.
What ice can do
Strain on the gutter. Ice expands and is heavy. It pulls on the gutter brackets and can open an old soldered seam. See
maintaining zinc work.
A cracked downpipe. Water that freezes in a blocked pipe can split the pipe or a coupling. You notice it in spring when water runs down the wall.
Water backing up. An ice dam at the roof edge stops meltwater from draining. That water looks for another way and can get under the bottom row of tiles.
Falling icicles. With a gutter above a door or path, that is a real safety issue.
What you should and should not do
Do not: knock the ice out of the gutter with a hammer or shovel. That is exactly how a zinc gutter gets punctured or a soldered seam breaks open, and you are standing on a ladder in winter while you do it. Do not use hot water either unless it can drain away, because it will freeze again half a metre further along.
What ice on the tiles means
A thin layer of ice on the roof after a cold night is normal. What is not normal is patches of ice that stay on one part of the roof while the rest is dry. That means there was water on or in the tiles there when the frost came.
With porous tiles that water sits inside the material, and every frosty spell pushes it apart a little more. If you see part of a roof staying white longer in winter, that is the spot to have checked in spring. See
porous roof tiles.
Frequently asked questions about ice in the gutter
