Soffit Vents


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Old 07-07-15, 12:31 PM
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Question Soffit Vents

An insulation contractor noticed that my soffit vents were not open, he recommended someone that can open them for me. My question is, should I have them opened before or after my attic is insulated?

Thank you!
 
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Old 07-07-15, 12:45 PM
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The soffit area should be cleaned and baffles installed to keep the insulation from falling back down in that area. The latter should be contracted to the insulation installer prior to his arrival. Yeah, he'll sell 'em to you, but you want it done right.
 
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Old 07-07-15, 12:50 PM
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What do you mean by there not open?
 
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Old 07-07-15, 12:58 PM
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The Holes were never cut out of the wood.
 
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Old 07-07-15, 01:12 PM
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So there is currently no soffit ventilation?
It will be easier to cut them open and install baffles before the new insulation gets in the way.
 
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Old 07-07-15, 03:42 PM
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The way I imagined it, the soffit guy will cut them open and the guy doing the insulation will install the baffels before he blows in.
 
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Old 07-07-15, 03:53 PM
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Some houses don't have soffit ventilation because the house wasn't built in the manner that they are nowadays, and the soffits are either inaccessible, or it may not be practical or wise to open them.

Some farm houses, for instance, might have 2x4 rafters that are notched to 2x2's on the ends... opening up a soffit like that would likely mean that you would have next to no insulation at all above the top plate... and half the insulation if you intend to create airflow in a 2x4 width rafter.

A farmer I know went with the advice of someone who wanted to open the soffits on his old 1900s 2 1/2 story foursquare house. He is quite angry with them now... When the wind blows, his insulation blows from one side of the attic to the other... and the temperature in the attic (which was formerly comfortable even in winter months due to solar heat gain) has dropped to near outside temperatures in the winter, which in turn has NOTICEABLY dropped the temperature in his upstairs bedrooms.

Just sayin. I don't know that you provided enough information for us to give a firm answer.
 
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Old 07-08-15, 07:11 AM
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It's a Gable Roof, Here is a picture.

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Old 07-08-15, 07:40 AM
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As X has mentioned, some features interact with others. Looking at your picture I see one gable vent ( I assume another on the other side) and a large overhang on the high soffit. I also assume there is a low soffit to the left. The starting point is to determine the targeted vent area for your entire roof/attic. Once you have that number you then need to divide that total up between the gable vents and both high and low soffit vents. I didn't see any mention as to having a ridge vent.

Once I have all of the vent locations and your total targeted vent area I can provide some guidance on where best to distribute the net vent area.

There will be more questions like vaulted ceilings inside, recessed lights, and side attics.

Have you currently been dealing with ice dam issues?

Bud
 
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Old 07-08-15, 08:09 AM
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No noticeable Dam issues. There are 3 bedrooms upstairs that are directly under the attic. On hot days they become very uncomfortable due to the hot attic. The Attic is 500 sq ft and is above the right side of the house (pic below). There are gable vents front and back and 3 ridge vents on the right side of roof. Contractor suggested opening 10 soffit vents on right side only, which is south facing and vent directly into the attic. North side(pic left) has vaulted ceiling and no ridge vents.
 
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Old 07-08-15, 09:05 AM
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What you are suggesting is far from the recommended ventilation, although it is a step in the right direction. My suspicion is, you aren't ready for a major project so perhaps best to see if they added soffit vents help.

However, expecting to cool that attic with natural ventilation is very optimistic. The air flow created even with ideal vent areas and locations is poor at best. Your best approach would be to address all major air paths from the house into that attic space, recessed lights, attic openings, chimney, plumbing, and the top of all the walls you can get to. You want to do this before you bury everything in insulation and your contractor should be aware of this. Then bury away, but include the air baffles and wind baffles to protect the insulation and provide an air path for the ventilation.

Bud
 
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Old 07-08-15, 11:39 AM
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Any downside of opening a few soffits on both the north and south sides?
 
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Old 07-08-15, 12:21 PM
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If the side with the cathedral ceiling has no air passage between the ceiling and roof [filled with insulation] then soffit vents on that side would serve no purpose.
 
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Old 07-09-15, 07:16 AM
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Good Point, should I ask them to use Durovent 23-1/2 in. x 46 in. Attic Ventilation System with Built-In Baffle?
 
 

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