I performed an assessment for a recent home buyer and the home inspector they hired when they purchased the home said the fiberglass insulation that is touching the roof where the roof slope meets the exterior wall may cause condensation issues and needs to be pulled away from the underside of the roof. The house was originally designed and constructed with no soffit, so there are no soffit vents. The top plate of the exterior wall meets the lower slope of the roof. To properly insulate the attic, I would think you would want the attic insulation covering the top plate. To ensure proper levels of insulation above the top plate, the insulation will be in contact with the lower area of roof slope. Since the attic does not have a soffit, I would think there is no issue with the fiberglass batt insulation being in contact with the underside of the sheathing? Since there is no soffit in the original design of the house the insulation does not limit the airflow ventilating the roof. The house does have gable and ridge vents for proper attic ventilation.
Is there an issue with fiberglass batts installed on the attic flat touching the underside of the lower slope of the roof if there is no soffit venting?
Soffit vents can be used for intake, but they are not the only means of intake. If you have a vented roof and already have adequate intake venting, you don't need to add more. Additionally, not all roofs need to be vented - there are "hot roof" designs where the rafter bays are insulated and sealed up. For more inquiry on ventilation contact to HVAC services experts at White Mechanical to get all your answers.
I have inspected attics where some but not all of the 4x8 roof deck has been replaced. I noted large amounts of black mold on deck panels that were not replaced. On those replaced, I noted black streaks or stains from the nail points penetrating the deck, When the ambient temperature drops below the dew point inside the attic, this is the first place you will get condensation.
The amount of moisture in the attic and the dew point compared to the ambient temperature is a simple way to judge the balance of the various factors that contribute to damage from inadequate ventilation in an existing attic.
Too many people attribute ventilation benefits to attic ventilation that are myths. The purpose of attic ventilation is to remove heat and moisture from the attic space above the insulation to avoid ice dams and condensation. That is it.
Home inspectors have no training in many things we deal with and balk at anything non-standard or which they have not observed.
"Too many people attribute ventilation benefits to attic ventilation that are myths. " YES!
I've gone round and round with roofers who are almost religious with their belief in venting as a cure for all evils.
The real issue is the connections between the attic and living space and the moisture that moves between them. I've actually seen attics with nominally zero venting be made much worse (moisture-wise) by adding venting - usually done to fix an ice dam problem.