An ice dam can form when certain parts of the roof get warm enough to melt the snow on the roof while the roof edges remain much colder and as a result prevent the melted snow from flowing down the roof.
Roof ice dam protection.
An ice dam is a ridge of ice that forms at the edge of a roof and prevents melting snow water from draining off the roof.
The minimum is typically 2 feet 24 inches or 0 60 m above the vertical projection of the inside of the exterior wall.
Expect to pay just a few hundred dollars if you hire a pro.
If the air in the attic remains cold enough it can never melt the snow lying on top of the roof.
You shingle over the top of it.
This can be done through a combination of.
Moisture entering the home from ice dams can lead to the growth of mold and mildew.
L shaped flashing made of steel can be installed by a homeowner or a roofer.
The best way to prevent ice dams is to ensure that the air in the attic or against the bottom of the roof deck doesn t get too warm.
Ice and water barrier is a type of self sealing underlayment that adheres to the roof decking and waterproofs it.
Chimney flashing another vulnerable area for ice dams is around the chimney.
Effects of ice dams.
The water that backs up behind the dam can leak into a home and cause damage to walls ceilings insulation and other areas.
For an ice dam to form the warm parts of the roof generally need to be higher than 32 degrees f while the cold areas of the roof need to be below 32 degrees f this means that the outside temperatures must also be below 32 degrees f.
Even if you don t live in an ice dam region like minnesota colorado and wisconsin you may still consider ice barrier membrane for your home.
Ice barrier roof material is used to protect vulnerable areas of the roof as an added layer of protection against ice and water damage.
Run special ice dam prevention products adhesive ice and water barrier from 3 to 6 ft.
Ice and water protector must reach above the highest expected level of ice dams which will vary by region and the slope of your roof.
Up the roof from the edge the next time you reroof fig.
This problem creates pockets of cold air that allow the melting snow to freeze along the roof edge.
Do it on your own and costs will range from 20 to 350.
Insulation similarly missing insulation near the edges of the roof and exterior walls can cause ice dams.
The main product used to protect the structure with ice dam protection from leaks is ice and water shield which is a 36 wide roll of bithane self adhered membrane that when applied to the roof deck will provide a water proof barrier between the roof shingles and the plywood substrate.
In colder regions a good practice is to cover the first 3 feet 36 inches or 0 91 m of roof over heated space with ice and water protector.