Five best practices reasons for using roofing felt underlayment.
Roof ice shield requirements.
The minimum is typically 2 feet 24 inches or 0 60 m above the vertical projection of the inside of the exterior wall.
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.
An important component of making your roof less prone to leaks caused by ice damming is an ice and water shield.
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.
The eaves flashing shall be installed from the end of the deck to a minimum of 24 inches up the slope.
All overhangs should also be covered.
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.
On 4 12 or greater slopes the balance of the roof shall be one layer of 15 felt.
Roofing ice and water shield is a critically component to any new roofing system especially in cold weather climates.
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.
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 the eaves of your home up to 24 inside the exterior wall this usually means at least 2 rows or 6 feet in every valley 1 row or 3 feet around every pipe before the flashing is installed along every wall chimney or skylight where flashing will be.