When does shingles become contagious?

When skin is broken: Shingles skin lesions have contagious viruses from the time the skin lesions begin to break (feel damp or sticky) until after the skin is healing, covered with dry scabs or dry skin. If there is any moisture coming through the shingles rash, then one can safely presume there are still viruses there.

Wet : As long the little blisters (vesicles) are wet/moist, they are contagious. Once it has fully dried up they it is no longer contagious.