You ve already determined that you are going to install metal roofing rather than just putting up new shingles so you need to remove the old roof.
Install metal roof without sheathing.
If your home s existing shingles are pretty curled you could install a textured metal roof such as a metal shingle shake or tile directly over the curled shingles along with underlayment.
You will want to do this on a dry and sunny day in order to minimize the chance of any water or moisture damage to your house.
You also could install a corrugated through fastened metal roofing product and probably not have issues.
Modern metal roofs are expected to last 30 years or longer.
Metal roofing is also available in the form of shingles.
Lay the starter row of metal shingles at the drip edge and affix to the roof with metal roofing nails.
Before you install metal roofing repair any damage to the wood under the shingles.
Next use 1 inch nails to secure some metal edging to the perimeter of the roof.
Chapter 8 includes specifics for such things as allowable lumber to use the moisture content of fire retardant treated wood allowable rafter spans and use of.
These requirements cover the design and construction of roof ceiling systems including roof framing roof drainage roof sheathing ceiling finishes roof ventilation and attic access.
When installing a metal roof over an existing roof insulate the spaces between the wood strips with rigid insulation to prevent condensation before installing the roofing.
You also need to add.