installation of natural passive vents
I just realized that I might have made an error on the installation of passive vents on my roof. I used 4 round passive vents with 144nfa for an attic that has 2500 square feet. I followed the calculations of the OC web site; soffit nfa appropriately corresponds to the 4 passive vents. However, I did not alter the openings of the old vents; they are 8" X 9" rectangles. I just noticed the instructions for the new passive vents state that there should be a 14" diameter in the cut out in the roof. That comes to 153 square inches compare to my 72 square inches.
should I do anything"? right now at 11:43 PM it is close to 100% humidity outside the house (weather report says 100% but it isn't raining) and according to my humidity reader in the attic it is only 44% (I closed the staircase, left the reader in the attic for several hours and just returned to read it; the reader gives me approximately the same readings as a downstairs dehumidifier that I have so I expect it is quite accurate). I will monitor over the next day. The last time I checked the temperature it was 89 degrees outside and 85 in the arttic. right now it is just a little cooler in the attic than outsider. Seems to be pretty moderate in all of this, so shoudl i do anything to correct the situation.
My roof is all in (except for some trim pieces on the ridge; I ran out). No leaks; looks professional and beautiful. But , if I do have to correct the opening can i cut it larger from insider the attic. What should I do at this point?
Last edited by Alto; 08-18-2010 at 11:57 PM.