Heat Loss Roof Snow

The problem compounds as more ice builds up or dams up and wants to get under the roof shingles and then water can potentially leak into the house.

Heat loss roof snow. Heat loss happens through the various elements of the building shell. Melted snow travels down into gutters or the bottom edge of the roof or roof eaves then cools off and forms ice. Walls roof doors and windows floor. Asphalt shingle roofs should remain covered in show if the temperature fails to rise above 32 degrees.

There are other situations in which sliding occurs. Yours seems to correspond with the soffit vents. To melt a kilogram of snow requires 3 34 x 105joules which is the latent heat of fusion of water. Over the other units enough heat escapes into the attics to melt most of the snow.

A 1 4 thick sheet of ice extends from the lower edge above the ice dam all the way to the ridge on this roof confirming that the under side of the snow is being melted by attic heat then freezing along the roof surface as well as accumulating as a built up ice dam at the roof eaves. Nonuniform roof surface temperatures lead to ice dams. In cold climates that leads to ice dams. Energy or heat loss can be seen on some uninsultaed roofs by the sight of snow melting as heta rises through the rooat id.

For ice dams to form there must be snow on the roof and at the same time higher portions of the roof s outside surface must be above 32 degrees f freezing while lower surfaces are below 32f. Snow makes it easy to see where your home is leaking heat through the roof. Heat loss from a house snow cover and outside temperatures interact to form ice dams. The attic needs to be sufficiently insulated and ventilated to prevent excessive heat loss.

Normally snow slides when heat loss through the roof causes the 0 c temperature line to move up into the insulating snow layer and melt snow lubricating the roof surface and destroying the cohesion and friction forces. It doesn t take much heat to melt snow on a 35 degree day. It could just be that the additional airflow in that area leads to more melting in marginally cold weather. The difference between this photo and the first is that the garage is unheated so there s just not much heat available to melt the frost on that side in the first photo.

The tiled roof line or ridge line of a house showing the tiles covered in a layer of snow during the winter. All homes have variation in heat loss. For icicles to form along the lower edge of a sloping roof when there is snow on the roof there must be thertnal energy flowing to the snow to cause the snow to melt.