I be wondering, roughly how much it would cost for someone to install a roof ridge vent on my 40 ft long roof
Answers: Don't waste your money, install powered vent.
Ridge vents are a right idea regardless of what the guy said within 1 of your answers. It will vent a lot of hot nouns from your attic and also increase your shingle life. There is better than a partly days work involved. Labor and materials I would guess it will cost you between $500. and $700.
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