Can you lay architectural shingles over three tabs?

On something small like a pumphouse top or small storage building you wouldn't have to many issues. On something larger like a house or garage its possible but it wouldn't be recommended. If you nailed the arts. over the tabs thewarranty on the arts. wouldn't stand, the two layers of shingles can break roofing codes in your area and could be to much weight on the type of roof structure you have.