I'd put at least one for each rafter bay. Depending on their size.
according to my obsolete references, your total ventilating
area(cross section) after accounting for any grillwork,
should be 1/300 of the roof area to be ventilated, evenly
split between soffit and ridge venting.
If the rafters are 16" apart, then that's around
1 sq. inch of ventilation for every 37.5 liniar
inches of rafter?
So, if a 2" round hole covered by screening
has an open area of around 5 square inches,
that's good for a 16" rafter bay between
15 and 16 feet long.
"Me too." wrote:
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.