As wood absorbs water it expands.
Roofing in the rain wet wood.
If you see that your roof deck is wet warped or wrinkled you should not attempt to reroof.
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.
Wet or rain soaked framing lumber will not rot in a matter of days.
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.
Homeowners often worry that the wood is ruined if a house gets wet during construction.
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.
Make sure your roof is completely dry before reroofing.
The above article mentions that the shingles won t adhere properly if the wood or water barrier is wet when the roofing is applied.