On Feb 25, 11:00*am, " wrote:
On Feb 25, 10:50*am, Home Guy wrote:



Bert Hyman wrote:
What "killed" our shingles was time.

Convection moves air from the soffit vents to the roof vents.

Dream on.

Convection will not move enough air during the dog days of summer to
keep your attic cool.

I have properly ventillated soffits, several passive vents AND a powered
roof vent that I manually control. *When I forget to turn the fan on
until noon on some summer days, it's not uncommon for my $15
battery-powered temperature sensor to read a temperature of 140 F in the
attic.

15 minutes after I turn the fan on, the sensor will be reading 120 f and
still dropping.

This is for a roof section that is about 35 feet by 30 feet with a low
pitch. *I'm in the same climate zone you are - I'm about 120 miles more
south than you, and a few hundred miles to the east.

Wind-powered roof turbines are a crock of ****. *Maybe you have some
sort of romantic or nostalgic attachment to them, but they will not do
squat to keep your attic cooler as compared to just having a hole in the
roof. *And during the dog-days of summer when there is no wind, the
turbine blades will actually HINDER convective air flow because of the
resistance to air flow they cause vs just having an open hole.

I upgraded some years ago from 2 tiny vents at each end of house to
ridge vent plus those existing vents.

Put my fluke recording temp probe up there before and after.

Before top temp 146 degrees

after 116 degrees

Incidently home inspectors say the spec is the attic shouldnt ever be
more than 15 degrees warmer *than the outdoor temp

90 degrees outdoor 115 TOPS in attic my home for sale was 119 degrees

at the home I was attempting to sell the inspector said I had to add 2
large attic exhaust fans.,

The buyers wife didnt want the fan noise so that issue faded away
the house had a ridge vent but no soffit vents and no place for soffit
vents

This will not make shingles last longer but will cool the space. I got
some perforated
aluminum/polyethylene sheeting and stapled it to the joists below
roof.
I used to walk into my separated garage in the summer and feel the
extreme heat from
the roof. Now, I don't feel any heat from the roof. A major
improvement.

greg