Recent Q & A
Ice and water shield has been around now for a while and some roofs where it was used now need re-shingling. Due to heat and adhesive, the roofs now are pretty well one solid bitumen mess and removal is next to impossible. It seems manufacturers never considered this issue when the product was invented. Any suggestions? I contacted Resisto on this and got no reply. Wonder why.
A great question, so I sat down with the Resisto technical expert to discuss the issue. We need to realize that the question we are asking is basically what to do 15 years later after the bitumen membrane had done such a good job of sticking where it was put. The person installing the roof is not likely the person replacing the roof years later, so has very little incentive to take measures to avoid having the shingles and the membrane become one solid mass well stuck to the wood. On flat roofs, membranes are best stuck to substrates such as RESISTOBOARD, a fibreboard substrate that allows for easily lifting old membrane roofing. But it is not used under shingles.
What you need is a separator at the time of installation that will prevent the shingles from fusing to the membrane, be it a full roof membrane or simply an ice shield on the lower edge.
Resisto’s high-end membrane, the LASTOBOND PRO HT-N (yes, the “N” stands for North; they also sell an HT-S for the South) has a plasticised topping that allows for removal of shingles years later without destroying the membrane, and the nail holes are still self-sealing. But few people want to invest for someone else’s job 15 years later.
The brilliant and inexpensive solution for eave protection sheets is to bring your roofing felt all the way down to the edge of the roof, right over the newly laid membrane. Then nail the shingles as usual and the felt paper acts as a separation sheet between the shingles and the membrane years later. If you are too cheap to use three feet more of roofing felt, then you deserve the problem. If you put a membrane over the entire roof, or use a lot of it around penetrations or transitions, then cover the entire roof with 15-lb. felt, something actually required for warranty with some shingles. This will have the same separation/slip-sheet effect between the membrane and the shingles.
They didn’t do any of those things on the messy roof that you are stuck with? If it is just eves’ protection, cut out the plywood on the bottom of the roof (a good opportunity to fix any soffit ventilation/insulation issues from the top) and lay down new plywood. If it is the whole roof, hog off what you can, pull the nails and then cover the uneven surface with new sheathing. But you are right: It would be nice if someone warned us of this down-the-road problem.