Snow and ice shield

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Was talking to a contractor friend this weekend, and learned that he considers snow&ice shield to be a bandaid solution to fixing roofing (much better to get the ventilation done right). Wish I had known that ten years ago when I had my roof done! Live and learn I guess (and yes, I have a leaking roof now). FYI. FWIW, if I could do it all over again, I wouldn't bother with skylights either--they let the heat out in winter, in during summer, and let in too much light in my bedroom.

According to him, if there is a gap, water can work its way under and lift it up, just like it can for shingles. I took a quick look, and found another way for it to fail. Link
 
A roof is a system of several parts and each needs to be chosen & installed properly. S&IS varies in quality and is dependant on the installer as is the roof. In your area, you need a cold roof in Winter. You also need a moisture barrier on the inside of the walls before the insulation, any holes in the top plates sealed, no leaks in ductwork, no interior fans exhausting into the attic, etc. The list is long and extensive to prevent ice dams.

Finally, my roofing nailer never left any wires attached like that!
 
Had new shingles put on roof last summer, to keep in compliance with code and shingle warranty it has to be installed, our home never had it on before and shingles were probably 25 years old (estimated) We never ever had a ice dam leak before even without it. But ice shield is required here. It is only about the first 4 ft of the roof edge. Was about an extra $130.00 for my little 14000 sq ft bungalow house. Normally only get ice dams on the north side of our house anyway, but we have heated gutters so it is not really an issue. I have seen people's gutters collapse due to too much ice and now they have gutter heaters.
 
I had hoped that snow&ice shield would mean it'd never leak (within reason). I knew the ventilation on that side of the roof wasn't the best, but, it wasn't that bad and the leaks I had were on the other side of the house (where ventilation was non-existent). And the contractor seemed to think it was a good idea, and didn't think the ventilation in my now-problem area was an issue.

So I had snow and ice shield put over the whole roof, but I think it's damming in the usual spot (just at the top of the wall). Could be up higher though, there is a wavy spot several feet above that.

All in all, not what I expected out of that roof job.
 
Snow & ice shield replaces tar paper for the first 4'. Maybe go 8'. Not needed on the entire roof. It's a better membrane than tar paper to prevent leaks but all the nails holding shingles still go through the snow & ice shield just like they would tar paper.

The proper way to prevent an ice dam is to have proper ventilation in attic.

Or do what they do in VT. Put copper or other metal sheeting for the 3' or 4' then start shingles.
 
Originally Posted By: Donald
The proper way to prevent an ice dam is to have proper ventilation in attic.


Pretty hard when the attic is finished. Next house, no finished attic. Too easy to do it wrong; if left unfinished, much easier to fix ventilation problems.
 
Originally Posted By: Donald
Snow & ice shield replaces tar paper for the first 4'. Maybe go 8'. Not needed on the entire roof. It's a better membrane than tar paper to prevent leaks but all the nails holding shingles still go through the snow & ice shield just like they would tar paper.

The proper way to prevent an ice dam is to have proper ventilation in attic.

Or do what they do in VT. Put copper or other metal sheeting for the 3' or 4' then start shingles.


Don't even use tar paper anymore. It's tyvek underlayment that's popular now. As I recall, it's supposed to be 4' over the heated area, but if you go from the edge, that's unheated so you should really do two strips so 6' instead of 4'. Also depends on the type, Grace is supposed to be better than Weatherwatch which is also cheaper.
 
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