Currently trying to get estimates to replace the T-111 siding on my CBS on slab home in Florida. Siding surrounds the attic between the roof and the cement block exterior walls. I'll be replacing the shingle roof at the same time, but none of the roofing contractors I've contacted will tackle the siding replacement.
So far only one contractor is willing to bid the siding job and am awaiting his quote. He's an older gentleman and has a long history as a reputable general contractor in my county. However, one of his recommendations has me concerned as to how "up-to-date" he is regarding building science and makes me wonder if he's a good choice for this job.
Both times he was at my house he told me he would put powered attic ventilator fans in the "gables" on the back half of the house, where the roof peaks in the middle. I told him he couldn't do that because the "gable" at the rear of my house does not back up to the attic, it's actually part of the wall in my family room, which has an open beamed ceiling. After he pondered that awhile, he then (twice) said he would put the fans in the siding at both ends of the front half of the house above the garage and the guest bedrooms. I told him I was concerned that powered attic ventilation would cause negative pressure in the attic and result in higher energy costs not only from running the fan, but also from pulling conditioned air up into the attic. He said that can't happen. When I asked if the fan would exhaust or intake air, he said it would be an intake fan. I didn't discuss it further, but I was concerned how the intake from two powered fans could possibly be matched to the exhaust space available through my off-ridge vents in that part of the attic so as to avoid positive pressure and infiltration of more hot attic air into my conditioned space. Also concerned about pulling in too much humidity.
Everything I've read online advises against powered attic ventilation in Florida. Comments?