There are several disadvantages to using felt underlayment on a roof.
Roofing rain on felt.
The material may dry out or leach oils in the heat.
This would impact the felt s ability to protect against moisture.
Gaf shingle mate 36 in x 144 ft 400 sq ft felt roof underlayment.
Shingles or many other roof systems should not be installed over wet felt in the past i would cut x s thru the bubbles but now imo that should not be done.
One disadvantage of traditional felt roofing underlayment is it generally can t be left exposed for more than a few hours.
Waterproof roofing felt gives the roof temporary protection from rain while you apply shingles tiles or other roof coverings.
It is safe to walk on.
One of the roofing pros we spoke with says mist won t affect osb any more than the humidity that osb absorbs on a hot day.
It provides backup protection in the event of ice or water damage.
In high humidity materials may bulge or wrinkle causing ripples and bumps on the exterior surface of your roof.
The decking sheathing should have been tarped and work stopped as soon as it was evident enough rain was going to fall to wet the wood or water barrier felt.
If it starts to rain or drizzle the roofers should act quickly to cover your osb most likely with a tarp.
Item 656632 model 0903000.
Roofing felt that has gotten wet can be covered with shingles as long as it is allowed to dry out first the surface underneath did not get wet and it did not wrinkle bubble or rip.
Many of the inner components of your roof such as barriers osb boards and felt are also sensitive to water damage and should not be exposed to moisture.
Having wet sheathing covered with tarpaper or membrane will trap the water in the sheathing very bad practice and contrary to industry standardss for roofing.
Felt that is rained on no matter how well its fastened imo will have bubbles it helps to let it dry out prior to roofing but bubbles will exist.