Attic baffles

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  #1  
Old 11-19-19, 10:24 PM
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Attic baffles

The other day, I had roofing contractors install attic baffles from the exterior while getting a roof redone. I specifically purchased DSI Smartbaffle, as I feel the design is very impressive. I showed the project manager a quick 1 minute installation video prior to them starting the work. Baffle placement isn't rocket science, so I didn't think too much could go wrong. Well...

Day 1, they started to install the baffles, and the project manager told me he was pressings baffles into the top plate so that if I decide to go with blown in insulation, I wouldn't have to worry about the insulation blowing into the soffit space. DCI has a wind blocking feature on their baffles, and I made it clear to him that he did not have to block off soffit entrance, since I was going to use batting insulation anyways. I didn't think to check their work, so I went about my day.

Day 2, the next day, they sent me close up pictures of baffle placement on another section of the house. Again, the bottom of the baffle was stapled right to the top plate. In addition, the baffle flanges were installed a couple inches lower on the joist, when the flange ideally should've been stapled at the top.

It appears I have more than enough airflow, but now I am concerned that the low placed baffle is compressing the R-38 insulation. When insulation is compressed, the r value gets lowered. Living in a category 5 region, I can't afford to go much lower than an R-38.

Should I worry about ice dam formation, given the r value reduction so close to the soffit space? Am I over thinking this?
 

Last edited by Smuly; 11-19-19 at 10:27 PM. Reason: Grammar
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Old 11-20-19, 05:17 AM
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There are different "over the top plate" methods for rafter framing. If your design provides extra space like a raised heel truss you should be fine. If your rafters have the typical birds mouth cut and rest directly on the top plate then you have ledd space above that top plate to start with.

A few pictures would help.

If the soffits are still open it would be nice to do it right. Not sure the contractor will be happy.

Bud
 
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Old 11-20-19, 02:43 PM
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How do I submit pictures as a reply? And I'm not sure I understand what you mean by rafter framing. I think if I show you the pictures, it will make more sense. They are coming out tomorrow to install the soffits.
 
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Old 11-20-19, 03:59 PM
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This link may help with the pictures:
https://www.doityourself.com/forum/e...-pictures.html

And here are some illustrations for soffit area.
https://www.google.com/search?client...cvgA7EQ4dUDCAY

Bud
 
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Old 11-20-19, 05:06 PM
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Can you help identify what type of soffit area I have? It doesn't look like I have raised heel trusses, which seems work against me...
The roofers over angled the baffles and stapled it a couple inches below the rafter peak. In essence, they gave me plenty of airflow but very little room for my R-38 insulation. Also, I'm afraid they placed the baffle very close to the recessed canned light in the attic space.

Are you able to email me for quicker responses? They are coming out tomorrow morning and I don't know how to present my concern to them. Do I have to purchase new baffles? Or just unstaple the bottom and raise up while soffit is removed?
 
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Last edited by Smuly; 11-20-19 at 05:32 PM.
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Old 11-20-19, 05:19 PM
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This is the shed roof, where the recessed lights are located. I'm afraid they placed the baffle too close to the container within the attic space. Do you see where they stapled the baffle flanges? DCI pictures showed the flanges stapled at the peak of the rafter. What's strange is that I called DCI and they said the baffle placement looks fine. When I asked about compression of insulation, they couldn't give me an answer-they said I need to consult with an insulation company. When I explained that Owens Corning made it very clear to me that with every inch you compress the insulation it lowers its R value, the sales associate told me he is too busy and he cannot speak to me anymore. Either I am overly dramatic on this topic or he has some significant customer service deficiencies.
 
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Old 11-20-19, 06:51 PM
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You have a traditional TCO (Top Cord Overhang) where the rafter extends beyond and below the ceiling joist.

I'll explain my concerns and we will sort it out.

1. To ventilate you need a low intake (the soffit vents) and a high exit for that air. I don't see what you are planning for the exit, maybe a smart vent from DCI?

2. The r-38 fits into the ceiling joists so the baffles do not need to go beyond the top of the joists, just enough so the insulation cannot block the air channel.

3. The air channel only needs to be 1" to 2" high, leaving the rest of the space below it for insulation. Those DCI baffles seem to want a 3" gap if installed towards the top, which they aren't.

4. The edge of the plywood is in bad shape.

5. I don't see the wind block tail I would expect. Looking for a flap that drops down vertically to the outside edge of the top plate.

I'll stop here.

Flashing at the wall above and the chimney need to be checked.

Bud
 
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Old 11-20-19, 09:16 PM
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1. The ventilation is taken care of. Continuous perforated soffits and ridge vents. For the shed roof, we decided to go with two box vents. The only sections we decided to not ventilate are the garage, patio, and under 10 sq. ft. Of roof for backyard kitchen entrance. Those sections would require specialty outtake vents, so we decided to forgo ventilating those sections. Plus, the rooms below are either outside space or unconditioned garage space.

2. We only installed one row of baffles in the insulated attic spaces, or 36" of baffle height. This provided us a means of covering the drywall with insulation while still maintaining a 2" clearance for necessary air flow.

3. What do you mean by the baffles wanting a 3" gap towards the top? The top plate? The smart baffle only is meant to provide a continuous 2" airflow clearance, if installed correctly. The flanges are to be nailed to the top of the rafter units. The flange is exactly 2".

4. What edge of the plywood is in bad shape? I had the roofers replace 4 ft. of plywood from all insulated attic spaces. Where does it look unhealthy?

5. Smartbaffle has a wind blocking feature, but you have to make it as needed. I did not need that feature, since I am not doing blown in insulation. For batting insulation, it is only required to install the baffles right to the top plate, providing continues 2" of airflow. The roofers decided to staple the end of the baffle to the top plate to re create the wind blocking feature, but in doing so, they are compressing my insulation below.

The chimney flashing was done last, once all the shingles were placed. In the pictures I send you, they did not get to that yet.

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Old 11-20-19, 09:51 PM
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These are example pictures of properly installed baffles for batting insulation. DCI reviewed my pictures and said they were placed correctly. But, to me, it looks like a contradiction to what I see being posted by them. Mine has well beyond the 2" airflow clearance while also unnecessarily compressing my insulation below. They said they don't deal with insulation so they can't tell me if their product will interfere with insulation performance. I was literally baffled by their answer, pun intended. How does a company make a product that is supposed to work in unison with insulation not know contraindications involving insulation? There is such a disconnect in the field of construction. The roof and attic work synergistically together, yet all the different specialists refuse to acknowledge the importance of co existence. One will fail without the proper installation of the other.
 
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