Replies

1. 
   Alan_Kim | Oct 16, 2000 02:45am | #1

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   Having it closer to the facia would serve the purpose of keeping most of the roof area "cold" as air is drawn in and out through the ridge vents.
   But I may get blown out of the water for making such a comment as there seems to be no shortage of absolute pronoucements when it goes to attic venting.
   (Maybe this discussion will turn into yet another duel of wits between the familiar experts in this group. In which case I will become a bystander....)

1. 
   Ralph_Wicklund | Oct 16, 2000 04:54am | #2

   *I don't see any hard and fast rules about actual placement of the intake vents in the eaves. Techniques for introducing ventilation include every position from the drip edge to under the decorative frieze and below the horizontal plane of the soffit.Examples of various types can be found in the pages of FHB and no negative comments made about placement location. The only caveat is that the ventilation should be balanced and of proper ratio to ceiling area.

1. 
   Gene_Leger_ | Oct 17, 2000 12:36am | #3

   *Gentlemen. H.C. Hinrichs in his 1961 ASHRAE paper, "Comparative Study of the Effectiveness of Fixed Ventilating Louvers" says "There is very little possibility of damaging infiltration in the soffit area if the openings are adjacent to the fascia and a mimumum of 8" from the side wall of the house." Remember, that the closer to the wall the greater the wind pressure.Hinrichs instrumented a real house in Princeville, Illinois in 1962. His findings, many of which I have quoted on BT, are based on the performance, or non-performance of attic ventilating devices installed in a real house attic. The attic ventilation in my book Complete Building Construction, 4th Edition, published by Macmillan,drew heavily on Hinrichs's research. A copy of his paper is available from ASHRAE(800-5-ASHRAE)It was published in ASHRAE Transactions, Volume 68, 1962. GeneL.

1. 
   Montana | Oct 17, 2000 03:41am | #4

   *Gene:After asking this question, I decided I should read some words of wisdom in your book. The explanation in there is quite sufficient to answer my question and makes sense, too. It's my pleasure to here from you, though.

1. 
   Gene_Leger_ | Oct 20, 2000 07:30pm | #5

   *Ralph. Did you know that the called for ratio of 1/300(which is claimed to give 1 sq. ft. per 300 sq.ft of ceiling or floor--depends on code--area)provides less than 1/2 sq.in per 300 sq.ft? .

2. 
   Ralph_Wicklund | Oct 23, 2000 06:52am | #6

   *Gene, I'm ignorant enough to not know what air engineers are talking about most of the time. My math tells me that if you have a hole, 12" by 12", which is 1 sq ft of surface area, and you ask how it relates to a ceiling surface area of 300 sq ft, you have a ratio of 1/300. Ventilation, movement of air, cfm exchanges, should they happen to occur because you have your hole(s), has no bearing on the simple math of the two areas.Now, as I understand it, someone determined that under average conditions an amount of air had to be exchanged to provide a certain minimum amount of ventilation benefit and the calculations of that exchange produced a number that translates to the ratio that we use. Code further defines that ratio to be actually 1/150 but 1/300 can be used if a couple of parameters are met.Your sentence, that says the 1/300 ratio provides less than 1/2 sq.in per 300 sq.ft. means ?????

3. 
   Gene_Leger_ | Dec 01, 2000 10:54pm | #7

   *Ralph. "Your sentence, that says the 1/300 ratio provides less than 1/2 sq.in per 300 sq.ft. means ????? " It means that you are not getting the claimed 1 square foot of NET Fre Ventilating Area. GeneL.

2. 
   Montana | Dec 01, 2000 10:54pm | #8

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   A recent discussion mentioned that eave vents should be at the fascia and at least 8" from the exterior wall. I recently purchased Tamlyn's vent that is next to frieze board on the eave (against wall). Why is this not good? I need to return them because they were damaged, so I'm not too late, but I must act fast: siding guy is coming. Thanks in advance.