It is excellent when it works, but a soffit and ridge ventilation system is supposed to move attic air.
How does such a system do that?
Physics. Convection. High pressure to low pressure. Heat seeking cold.
It never fails.
Ideally a 50/50 ratio of air is coming in and going out.
Even a 70% in and 30% out works.
Or a 30% in and 70% out.
The 50/50 may never be possible with wind and such. But still, the air has to be able to move.
With plenty of unblocked intake locations under the gutters and a nice slice out of the ridge of the roof, 3" or 4", things will work well.
If air moves, this ventilation system never fails. It can't fail. Air flow is dynamic. Physics follows principles that don't fail.
So, when I arrive at a new construction inspection to look at the house pre-drywall, and I see a ridge vent installed on the top of the roof, I will be looking inside too to see how well things are put together.
In this house, when I got upstairs and under the ridge vent you see in the photo on the left, I looked up!
There was very little ridge vent opening!
It was nearly completely closed off with building materials.
No slot for the air to escape was ever provided, or cut out manually.
That means the roofer, on top of the roof, looking down and seeing that there was no opening present to allow for air to exhaust, INSTALLED THE RIDGE VENT ON TOP OF THE ROOF ANYWAY!
One would think that a roofer would know that without a slot for air to escape the air, um,
CANNOT NOT ESCAPE!
But he installed the ridge vent anyway. He installed a ridge VENT over an area that cannot VENT!
Nothing to see here! Nobody will know! Who will be able to see this when the drywall gets installed?
Does the roofer think he can get away with this because he knows the supervisor either will not notice or will not say anything?
I bet both the roofer and supervisor understand how a soffit and ridge vent system works.
I bet both the roofer and supervisor understand that soffit openings have to be created and preserved for air to get in, and then a sufficient slot cut into the ridge so that air can get out.
My recommendation: there are many hundreds of things looked for on a pre-drywall inspection. This area may or may not be visible once the drywall and insulation are installed. On new construction the builder does not like for the home inspector (if there is one) to walk around the attic on the new insulation, so making it over to this location to see it might not have been possible later. a pre-drywall inspection is the only time to really see this with definite observation. So get a pre-drywall inspection! It is your personal Best Practice.
Jay Markanich Real Estate Inspections, LLC
Based in Bristow, serving all of Northern Virginia.
Office (703) 330-6388 Cell (703) 585-7560