metal ridge vent cap VS. roll type ridge

I was wondering what the inherent drawbacks are to using metal type ridge cap are? Besides the obvious possibility of denting, why is roll type ridge cap the preferred seemingly perferred product? The metal type ridge venting ridge cap seems to be much more economical.
Replies
Well, if you're talking about a shingle roof, the rigid plastic units are probably best. The roll type vent is much inferior in terms of effective opening area. The metal ridge caps are essentially identical to the plastic ones, only not designed to be shingled over, and therefore not as attractive.
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