Wet Tar Paper

How bad is it to shingle over wet tar paper. The paper has dew in the morning so ive been wiping it down with towels or old shirts and then waiting until it dries completely. The only problem is that the house has trees on the east side so its like 9 o’clock until i can shingle and even longer until the west facing side gets sun and dries. Would it hurt the shingles or decking to shingle over the dew? What about if it is sprinkling? Raining or just rained? Just curious if anyone has any opinions or better yet, facts from previous experiences? How many people have shingled over wet paper and did it cause premature shingle or deck failure? Also, does it matter if the paper is wrinkled? Will it lay flat after shingles are installed.

I sually cover with tarp if its gonna be dewy…i hate when it wrinkles,#30 felt i would wait till it smoothes out #15 not as concerned…

Facts not opinions can be found @ Gaf.com.On left side find underlayment and leak barrier specs.Click on it,and it will give the facts and observations data.I already know the answer.No to felt flattening and drying after it is covered,and yes the shingles will prematurely fail…Not opinion,but fact.If it is easier for you,P.M. me,and give e-mail and I can send you pdf. I have already downloaded from Gaf.
It sucks to wait for felt to dry,but it is worth the wait…The best thing to do is cover felted roof with tarp at night to avoid this situation…
Hope this helps.

If you only shingle over dry felt you would only get about half or a little less work done in a year in the Pacific Northwest.

Know what ya mean…you could also slice where its wrinkled then patch it with dry stuff…

Tarp it or shingle it…
Never leave just felt overnight when possible


Just stating facts,not saying you can’t do it.I however don’t.Yes it makes it difficult to make $$$,but it is the right thing to do…I have also tarped houses like a tent to work through a rainy week…Another full re-sheet…I’m guessing from house build in winter,and the last roofer covered wet felt…
I ripped of a cover over once that was soaked between layers,with no sign of leaking.The new layer was flawless,but when the h.o. went to clean out gutters,he stepped through the roof,called me,and it ended up being 2 layers off,and full re-sheet…The last roof was only 5 yrs old,and h.o. said they had to shovel snow off to shingle it.
From this I experienced 1st hand the effects of shingling over wet,IT NEVER DRIES! :shock: lol

ok I have a question. If you have ice dams and water gets under the shingles, you’re telling me that water never gets out?

I was just gonna post the same question.

Any ice damming issues I have dealt with,was remedied with full tear off…and I replaced wet sheets,install I&W shield,and new roof…so I don’t know…I only know what I’ve observed, and what I have read…I would imagine that the bulk of the water runs out,but the felt,and sheets will not dry out…
I have replaced so many sheets in the past few years,that it is not even funny.I am always asking history of the home.I am sure that most of the homes I’ve had to do full re-sheet were caused by framed and sheets were soaked before roofer got there,shingled in the rain,roofed in the winter, shoveled off by roofer,and lack of vent…
I’ve seen roofers shovel off a new house roof,and paper right over the frosty crusty sheets…Draw your own conclusion…Oh yeah,I’m starting 1 as soon as the rain lets up,and guess what?Full re-sheet…go figure… :stuck_out_tongue:

It has to dry with that kind of heat pumping in the house

the trick is to use a leaf blower and it will dry and flatten quickly.

Maybe climates make a difference too.Almost all of our work comes from word of mouth, but it doesn’t matter how good a reference they got if I doubled my labor prices the closing rate would be pretty small.

Thanks everyone for the help. Your responses were what I figured which is why I haven’t been shingling over the wet paper. Just trying to get more done during the day. I get annoyed when im standing around for an hour or so bc all the paper is wet and everything is set up for the day. Maybe ill have to invest in a leaf blower and use it after I wipe down with towels.

Mitchy –

#1 - Forget the towels, the leaf blower will kick but compared to a towel.

#2 - See Shangle’s post. The felt will continue to dry. Shingle’s are a water shedding system, not a vapor barrier.

#3 - Since you are doing your own home, what ever make you happy.

Try synthetic undies. They don’t wrinkle and aren’t much more than felt. Most need to be applied with cap nails or they can leak.

That is also why I am stuck on Shingle Mate,It does not wrinkle like reg. felt,and in 15 min. on partly sunny day it dries out,and is flat as new…I have been caught in passing t-storm,and couldn’t get covered with a tarp quick enough.
I usually strip from top down,and dry in as I go,replacing sheets along the way.If it is an ugly day,I also have the tarp ready to drape over it.
Leaf blower does work well…

Problem with felt getting wet and drying is when it dries it shrinks and tears away from fasteners. Whats the point of using an underlayment if it has holes?

Shingle Mate doesn’t have that problem.

Its code.