Roofing ice and water shield is a critically component to any new roofing system especially in cold weather climates.
Roof ice shield requirements.
Many local building codes require ice and water shield and national building code states ice and water shield must start at the roofs eave edge and extend 2 ft inside heated wall space of a structure.
All overhangs should also be covered.
If you have a more complicated roof with valleys skylights dormers vent pipes or chimneys it s a good idea to have ice and water shield installed in and around these areas as well as along the eves.
This code implies that ice and water shield eaves flashing is required for installation on all heated steep slope structures exception is unheated structures in colder climates.
On 4 12 or greater slopes the balance of the roof shall be one layer of 15 felt.
Eaves flashing is required to prevent ice formation at the eaves and gutter to back up beneath the roof covering.
The minimum is typically 2 feet 24 inches or 0 60 m above the vertical projection of the inside of the exterior wall.
This is a code requirement in cold weather states.
On roof slopes of 2 12 to 4 12 the remainder of the roof shall be two layers of 15 felt applied in shingle fashion or 1 layer of ice dam protection.
The eaves flashing shall be installed from the end of the deck to a minimum of 24 inches up the slope.
Where is ice water shield needed.
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.