When to lay shingles


My father is in the process of roofing his house (20 sq) on his own (with my help when possible). He wants to do this job himself and cannot do it very timely (which he is OK with).

I figure the job will take approx 4-6 weeks.
Each weekend we able to tear off shingles, put down new board and put down ice/water shield on 1/4 of the house. It works out perfect tearing off 1/4 as each side of the house has a small dormer that seperates the house into quarters. (yes, he is putting down ice/water shield on entire roof as it is only 20 squares and the stubborn bird thinks its better)

Our question is this - my father thinks we should tear off, re-deck, and ice/water shield the ENTIRE roof - then apply the shingles last as he thinks the ice and waters shield will give him enough protection for a few weeks (along with plenty of tarp). I think we should lay shingle after each 1/4 of the roof is ready so the house gets buttoned up and safe. we should be able shingle 1/4 at time without issues because the dormers splits it up nice.

Of course we would wait on installing the ridge vents and caps until the very end!

Maybe it doesn’t matter either way but I wanted to get your opinions!

As always, I appreciate your responses!

He shouldn’t be applying ice and water barrier to the entire roof but I guess you know that already. Make sure to run felt paper over the ice and water or suffer later when you need a repair. The shingles will embed themselves in the I&W without a buffer of some kind.

If the job is going to take that long I’d probably complete it in pieces. You could do a good “dry in” with I&W and felt that would last 6 weeks but you’re taking a chance and I don’t think those product should be exposed to UVs for that long. Check the manufacturer’s recommendations on that one.

Either way is good.
Whatever works best for you.
Ice & water shield will keep the weather out for a long time, if applied correctly.
Use Grace.