Thread: roofinf cement/lead boots/ shingle underlayment

I belive i am correct in that roofing cement is generally not compatible with galvalume metal roofing as well as lead boots. I also noticed this roof was installed over an old shingle roof with no slip sheet or protection between the two. the picture also shows this do it yourselfer installed a utility room and added the metal roof which really appears to lack proper pitch, but he sealed the seam with roofing cement. what do you think?

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Jerome,

It's not that they "are not compatible with" metal roofs, it's just that they are "not to be associated with" metal roofs and that the proper flashings are required to be used.

The proper flashings are required to be used for each roof system, and those are neither proper for metal roofs nor are they designed or intended to be used with metal roofs.

Jerry, what about the shingles undert the metal?

Originally Posted by Jerome W. Young

I also noticed this roof was installed over an old shingle roof with no slip sheet or protection between the two.

Not good either.

Many DIYers install metal roofs over shingles themselves and do it all wrong, which that seems like, and looks like.

Probably not permitted either.

Well I hope the shingle roof underneath is still in good enough condition to hold out the rain. A non asphalt underlay is required on metal roofs, anything asphaltic will melt (especially in Florida) and stick to the metal and cause all kinds of problems. As far as the plumbing vents and goose neck penetrations, looks like they just cut around them and gooped the up with mastic. Lead flashings can be used with metal roofs, but not as pictured here.

I think they will have problems down the road with that application, they will have to keep maintenance on the mastic and will probably start running down the metal in summer.