Not glamorous, but important. Proper attic ventilation and insulation provides numerous benefits including longer shingle and deck life, reduced heating/cooling bills, reduced moisture retention, and a reduction in ice dam related damage. Pictures below show damage resulting from improper ventilation and insulation.
Although a new roof with a new ridge vent was recently installed, no soffit ventilation was provided. Also, attic insulation was less than half of what it should have been (min R-38). The accumulated attic heat and moisture was not being removed.
To improve the conditions, we cut (ripped) a channel along the soffit, on both sides of the house. Since the gutter had been pulled from the fascia, we removed all of the old gutter and wrapped the fascia in aluminum to prevent rotting and the need for future maintenance.
To determine the type of soffit vent to use, simple math is used. The ridge vent has an exhaust coefficient of 18 sq. in. NFA/ft. Therefore, the soffit intake ventilation should match. The continuous soffit measures 9 NFA. Front (9 NFA) and rear (9 NFA) intake values equal the ridge vent exhaust value. The NFA is listed on the product spec sheet.
The existing insulation was blocking the intake air from our new soffit vent, so insulation baffles were installed. Not a fun task, below.
Once the baffles are installed around all of the soffits, fiberglass insulation is blown over the existing insulation. Code requires approx. 1 ft. of insulation equaling an R-value of 38. We typically install 1.5 ft. of insulation, providing R-50+.
The final task is the installation of the continuous soffit and gutter (seamless 5 in K). We try to do this last to keep the insulation overï»¿spray from covering the vent. In addition, exhaust vents (bath and kitchen) need to be exhausted through insulated ducting and discharged to the exterior, and recessed non-IC light fixtures need to be properly protected (top hat) and insulated.