[kw151002]

If I strip the old shingles off and put down the #30 do I still need to cover it with a tarp in case it rains or if we have heavy dew?

 

[Just Bill]

For a day or two, but no longer. There are newer roof underlayments that allow the roof to breath, and can be left uncovered for 6 mo. A big improvement over felt. Consider one of those. GAF Deck Armor is one.

 

[Scuba_Dave]

There have been threads on here where roofers have commented that felt when wet will wrinkle. That will then show thru the shingles. They recommend covering the tar paper

 

[kemp]

I had a house with #30 felt on it through several light rain storms (very little wind). The felt held up just fine.

But, chances are, if you leave it exposed for more than a day or two (or if it gets wet), you will need to re-do it. Felt wrinkles quickly. Just allow yourself enough time tear off the felt and re-do it if you plan on leaving it there for more than a day or two.