In a Ridge Vented home, or even if you have static turtles on your roof you depend on up draft to clear out the warm to hot moist air. Our old home had gable ends, during the heat of the day if you stood next to the eaves you could feel the heat pushing downward. The attic could not displace via gable ends the heat because of the low pitch of the roof so the heat would actually push down into the inside walls and exterior walls then push out the soffit vents.
Basically the reverse of what attic venting is all about.
When you see a soffit vent or that concrete board with thousands of holes all around your home I want you to know that the air is to be drawn in from the eaves not pushed out the eaves.
If you block the path of air that should be entering the attic you reduce your draft and trap hot moist air.
You are defeating the whole idea of ridge venting.
You should install air channels or baffles to assist the warm air up from the cooler air around your eaves.
The pictures don't lie, if you blow in attic insulation and don't use air channels or baffles from the vented soffits you just wasted $25 to $40 per 2' x 8' of Hardy Soffit panels.
One of my favorite reads is JLC Online [The Journal of Light Construction].
The link I shared is to an article that I think you should read both contractor and homeowner.
From that same article here's a snip:
"Nearly everyone in the building industry knows the 1:300 or the 1:150 vent ratio the code includes (see IRC 2015 R806.2 Minimum vent area): “The minimum net free ventilating area shall be 1/150 of the area of the vented space." Read my form The Journal of Light Construction.
Your insulation people should know this and should not have filled the soffits with spray in insulation to the point it covers soffit vents.
Image above shows spray in insulation covering the soffits that are designed to allow cooler air to enter from your the area around your roofs eaves.
In the picture below is the same house with expensive Hardy Soffit panels installed nicely. They become money wasted when the attic insulation covers the vent holes.
The very basic design is not difficult to follow. Here I'll share with you very low cost ways of correcting this issue but also what to look for from your builder before you make that final payment.
Let's see what our local box store can offer us to correctly install attic venting in the southern states when we mix a few codes in the design process. My wind code here at Camp Don is 130 mph. That means everything falling is falling and being blown vertical at 130 mph more or less. As a motorcycle rider what rain feels like at 85 mph on their face.
Image below is from 2015 International Residential Code via FEMA 2015 IRC - A Compilation of Wind Resistant Provisions PDF.
I can not say it enough and if you need me to do it, I will stand on our roof and yell it outloud!
STOP THINK! When it says the product is rated for less than what code calls for it's not to code.
I'm not interested if you got it approved. It's not to code, your inspector may have missed it. So when you install that "Breathable UV filter protects against wind-driven rain up to 110 MPH and helps prevent dust and insect infiltration" and the winds are 130 MPH you have no one else to blame for the water damage that may have been prevented.
We roofed our home years ago when the wind zone was 100 mph to handle 130 mph. Today we are rethinking some of our roof designs in light of the 130 mph ratings. Your builders and contractors should know this. Now you know it too. This means, no mistakes, you both can control quality.
After reading a few of the main suppliers of the national big box stores I'm thinking they aren't wind rated as I would have expected. They claim poorly fastened ridge vents are the cause for water entering the home during a high wind storm.
I feel it's not correct but do have a an idea to secure what you have in place.
Use #10 screws stainless steel is bests.
You will be more interested in air flow with the ridge vents that provide air baffles.
Now, interesting enough, closed attics vs. vented attics might be worth looking into. For us much of the normal building methods have changed now that we are elevating. Imagine having air ducts below your floors. As I research I'll update. We will be talking with a few contractors to get their professional experience down here in Louisiana living in a 130 mph or greater wind zone.