I have a 50 yr. old house with about 10 inches of insulation in the attic (gabled roof) and individual soffit vents in the. There are two old gable vents at either end. I recently replaced the screens, and the louvers are slanted about 2 in. apart. The vent diameters are around 18 in. Do I still have to install the rafter vents where there are soffit vents? I checked in the attic and there is light coming in where the vents are and they are not obstructed. Does it make any sense to still put in the rafter vents? Would there be any advantage for me to spend the money to have 2- 10 ft. ridge vents put in? I'm really confused about the second issue. I don't see any condensation on the roof underside but it is very warm in the attic when the sun heats up the roof during the summer. Or would I be better off renting an insulation blower and adding 3 in. of insulation(cellulose) into the attic?
Answer:
Normally, metal roof caps serve as ridge vents by design so there should be no need for the extra cost. As far as adding more ventilation under the eaves goes, as long as you can see daylight along the lower edges of the roof there is no need for the U channel vents. If, on the other hand, you do not see lots of daylight, you have no lower attic ventilation and that's not good.
