Roofing, Gutters and Waterproofing - We're getting a new roof - anything to watch for?

Roofers will start on our roof tomorrow. We're going from lathe and cedar shingles to decking and composite. They said it's a 2 day job since they have to deck it out. I'll be around part of the time. Is there anything I should watch out for or ask about? Thanks for the advice.

This is a VERY LOUD thing to have going on at your house, first of all. No conference calling from home those two days. Second, I would make sure the job is done as it is today, same number of turbines, vents, etc. No chinching out and doing fewer tomorrow than it has today. All the banging around up there may knock some things loose like your vents from your dryer or exhaust from bathrooms or things that may go up into your attic area... watch for items to reconnect post roof job. Get a hose. Hollywood movie set style fake rain on the house -- watch for leaks. Esp around flashing areas like your chimney if you have one. Those areas need to be sealed and sealed again. If you really want to make sure it's done right, call a home inspector to double check the work afterwords. Maybe for $100 he can do a roof inspection. Worth the call to me. Call the roofer back out immediately (before they leave town, sometimes not local crew) BEFORE you pay them if problems noticed to make sure all is well! Good luck.

If you are going with architectural shingles, check the shingle package for nailing configuration. Mine called for 5 nails per shingle. The roofer balked, but had to warrant his job through the manufacturer's requirement, so they did it. Make sure all drip edging is installed, proper flashing at chimney or transitions (step flashing is best). No silicone, no caulking, as their job should be waterproof enough. Have them include in their price all flashing, vent boots, ridge vent.
I would only recommend, at this point that you abandon any whirlybird or power vents on the roof and go with ridge vent system. All your hot air seeks the highest point, which is the ridge. Since they are decking it, leaving a ridge vent is simple and a lot less work for them than cutting all those potential leaks holes in your good roof. Most of all, if you can, watch them do the work, or at least get a feel for them as they go along.

Thanks for the hints - I already told them to do ridge venting - we have a power vent now. I'll watch the chimney flashing since that had started leaking on the old roof.
thanks!