Roof waterproof sheeting

[MGN]

My dad has been talking to me about a product he has heard about in colorado for waterproofing roofs. It is a tar like sheet that comes in rolls like tarpaper and sticks to the surface making it completly waterproof. Not only that he says that it is self healing, meaning you can drive a nail into it and pull it out and it remains water tight. He thought the name he was given was snow seal but i cant find any such product under that name. Anyone you what he is talking about or where to look to find such a product? Thanks

[HarmsWay]

Ice and water shield by Grace?

http://www.graceathome.com/pages/roofingprod.htm#I_AND_W_SHIELD

There are similar products from other manufacturers as well.

[dwegelin]

Has anyone had to re-roof over this material? Because existing felt is easy to remove but this stuff looks like it would be a drag to removed existing shingles from. Although it does say you can layer over this underlayment if needed.

[Progressiveauto]

Apparently no one has dealt with this yet but I am curious as well! I would think that you would just remove the old shingles and leave the ice-guarding in tact shingling over it again.