Step by Step ProjectsTips from the ProsAffordable Remodel
Always strip- always check the roof sheeting carefully (especially nailing: 4 inches at edges and no more that 6 inches in the center)- always use top-grade underlayment (and ice shield in colder climes). Locally they have just changed the codes to require stripping for all re-roofs- only one layer of roofing is now allowed.
Having repaired the effects of 5 layers of shingles on a sub-standard rafter system once I know it's not worth the cost saving to leave that extra weight. Had that homeowner not been underwater and in love with the house they would have been better off selling at a loss- we had to replace everything above the ceiling joists.