What type of underlayment do you want?
Underlayment is a protective water-deterrent covering that goes over the decking and underneath the shingles. There are primarily two types of underlayment: tar paper and synthetic underlayment.
Felt Paper Underlayment
Felt underlayment comes in two sizes--15-lb tar paper, or for steep roofs, 30-lb tar paper.
Synthetic underlayment is slightly more expensive but it is more effective when it comes to preventing water leaks. It is also much safer for the installation crew to walk on.
Should I get a leak barrier?
Leak barrier (also called Ice and Water Shield) is self-adhered roofing underlayment made of a rubberized membrane that acts as an extra barrier for problem areas such as valleys, walls, and eaves. In most states this is code enforced. We always line our valleys with Ice and Water Shield; however it is optional in Kentucky along the eaves of your home. It is worth adding on to the cost of your roof to ensure your home is leak-proof.
What type of valley should I have?
Another option to consider if your roof valley. In Northern Kentucky and South Ohio, there are 2 types of roof valley that are used most frequently: