The second underlayment is a tear and water resistant material that covers the remaining areas of the roof deck and also provides a high traction walking surface that increases safety for the contractors installing the roof.
Use roofing underlayment on fence post.
Apply drip edge to the eave.
Roofing felt is a layer of tar paper installed beneath the shingles to provide a backup waterproof membrane in case of leakage.
Valleys should be lined with a full width of roofing felt or bituminous membrane pushed tight into the valley so there is no slack.
If we were discussing an old fence post loose door.
Is it necessary to use roof underlayment on your home.
Cut drip edge flashing at an angle at the corner press it lightly against the eave end not too hard or you will misshape it and drive a nail near the end.
The most important reason to install underlayment beneath a metal roofing system is to prevent water damage.
Why does metal roofing need underlayment.
Once the shingle underlayments are in place the stage is set for the shingle installation and you can rest well knowing.
See best practices guide to residential construction valley flashing page 59.
Primarily the underlayment is there to stand as a barrier between moisture and the roof deck preventing damage caused by wind driven rain that may infiltrate seams or water that might seep in around fasteners as things like snow and ice start to melt.
Your roof is a much more complex structure than you may realize.