If the sheathing or wood is wet during the time of installation it can trap moisture inside of your roof leading to mold rot or other severe problems.
Roofing in the rain wet wood.
Wet or rain soaked framing lumber will not rot in a matter of days.
Not only does this violate building codes but your roof just won t last if installed atop a wet base layer.
Note that you should never shingle over bare wood like a bird s feathers shingles shed the qwater but are not watertight especially in windblown rain or melting snow conditions.
The above article mentions that the shingles won t adhere properly if the wood or water barrier is wet when the roofing is applied.
Know what to look for.
Make sure your roof is completely dry before reroofing.
Water can cause problems if the lumber is allowed to stay wet for weeks and weeks so do whatever is possible to get a roof on the house.
As wood absorbs water it expands.