I'm fixing to construct a metal roof to replace my asphalt shingle roof. I have 2 main questions:

1. Do I need to remove the old shingles? There is only 1 layer & most metal roofs I'm aware of simply left them in place.

2. I've been approached about a solar insulation to be placed under the new metal. The salesman stated that it would serve as a moisture barrier as well as have an aluminum backing to reflect or decrease heat transfer from the metal through the attic & into the house. I'm sure it is helpful, but it is also costly @ $0.40/SF. This is also new to me as most metal roofs I'm aware of were simply placed directly on the old shingles. I've read where this solar insulation could possibly save up to 40% on energy bills, but won't the metal itself reflect much more than asphalt shingles... even a dark metal.

These are the 2 issues I'm seeking advice on right now as I begin the process of lining up materials. I appreciate any help or advice.

My boyfriend is a contractor for many yeas. He read this and this is his advice. Put down strapping, then apply metal roof. He say's you don't need the solar stuff, it's just a salespitch, you already have a moisture /vapor barrier with old shingles. If you were going to rip the old roof off then you must ice/water shield the whole roof. That's the best way. Depending on your location and the snow load you might want to get rid of the extra weight by ripping the roof. Highlly recommend it Hope that helps.

Please excuse my ignorance, but what do you mean by "strapping". Is this placing slats across the roof at a specific interval to screw the metal sheets to. Also, what is "ice/water shielding"? I live in Texas but do get some snow/ice storms through the winters. Thanks again

You are rite about the strapping. And you should just go over the old roof ( with the strapping first than the roofing) I live in new england

So there is no need for a barrier between the old shingles & metal, such as felt or a solar insulation. I've heard that metal can conform to the shape of the shingles below & appear wavy. Does the slats or straps help alleviate this deformity.