Anonymous wrote:Proper venting of attic is fairly important. When we custom built our home, we specified the soffit (hardi), ridge venting, roof insulation (r49) and the baffles at edge of roof rafters which keep blown insulation out of vent routes. When you go into the attic, you see white light all around. We have ZERO mechanical (power fans) venting on a 12ksqft home. Best venting is passive - ridge/soffit but it must be appropriately sized and executed. The benefits have been significant- extremely low energy bills and no ice cycles (no ice dams). Builders almost never do it right. You will need to carefully inspect the work.

"Builders almost never do it right. You will need to carefully inspect the work."
What, exactly, do I look for to be sure my builder has done it right?

Proper venting of attic is fairly important. When we custom built our home, we specified the soffit (hardi), ridge venting, roof insulation (r49) and the baffles at edge of roof rafters which keep blown insulation out of vent routes. When you go into the attic, you see white light all around. We have ZERO mechanical (power fans) venting on a 12ksqft home. Best venting is passive - ridge/soffit but it must be appropriately sized and executed. The benefits have been significant- extremely low energy bills and no ice cycles (no ice dams). Builders almost never do it right. You will need to carefully inspect the work.

Thanks so much!

You need the same area of vent at the ridge as at the eave.

This is all dictated by building code, a competent roofer should know this.

Anonymous wrote:You really need both soffit and ridge venting - low and high to pull the air through. If you can’t get enough low venting then look into high powered vents.

Attic venting solves a very particular problem. In cold weather, the air inside the house is warmer and more humid than the air outside. When inside air leaks through the ceiling and into the attic, the moisture in that air can condense when it hits the cold underside of the roof. If that condensation is allowed to happen it can cause mold and rot in the framing of the roof.

The purpose of roof venting is create an air flow that dissipates the moisture that is entering the attic through the ceiling.

The problem with power venting is that it tends to pull air through the ceiling. Rather than venting moist air, it pulls more moist air into the attic from the living space. It also tends to make the space below the ceiling less comfortable.

If you go up in your attic and look down towards the eaves and see daylight chances are there’s enough air sneaking in to the attic to allow a Ridge event to function properly.
If you don’t see light or insulation is packed up to the edge a SmartVent would be a good choice.

But first you would want to see indicators that your house does need ventilation improvement, there are millions of houses constructed without ideal attic ventilation and they are just fine, yours may be one of them and someone may be looking to sell you a solution for a problem that you don’t have.

Take a look at the roofing nails that poke through the roof decking on the interior of the attic, are they rusty? Looking at those same nails are there little gray/blue streaks on the wood where the nails come through? Rusty nails and streaks on the roof decking bisecting through roofing nails are indicators of condensation at some point and if you see them then chances are your attic could use a little ventilation improvement. If the male tips are clean and there are no streaks on the roof decking then your house is running just fine and a ridge vent would be an adequate and inexpensive addition to the system.

You really need both soffit and ridge venting - low and high to pull the air through. If you can’t get enough low venting then look into high powered vents.

OP here - its smart vent/fascia vent. thanks again!

We're looking into replacing our shingle roof and wondering if upgrade to smart vent or soffit vent is worth it or is ridge vent sufficient? We have an attic and recently replaced insulation but no fan. Thanks!