Insulation in Attic


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Old 02-10-14, 06:34 AM
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Insulation in Attic

So I crawled up in our attic for the first time this weekend and took some pictures. I am pretty sure the attic isn't insulated properly do to it being very hot on the second floor in the summer, cold in winter and draft windows. I want to make improvements/add insulation if needed but not sure where to start. Attached are some pictures. I noticed that there is some "dirt" around the insulation on the drywall cover which I'm assuming shows air infiltration. So I definitely need to seal that better. I also noticed that there are some low insulation spots (like 6 to 8") that will need to have additional insulation. Some questions I have are:

1. How can I tell if there are other air leaks? Do I just look for pipes leading down and then dig the insulation up around them?

2. I think the HVAC vents leading down into the ceiling in one of the bathrooms and laundry room are just foil ducting (or similar)....should they be tin or is this okay? Shouldn't they be totally covered in insulation (I've noticed the air coming out of the one in the laundry room is slightly cooler then the rest of the room when the heat isn't on).

3. Is the venting in the attic okay? Not sure what is recommended.

4. I couldn't tell if the insulation in the vaulted ceiling is accessible.....what should I be looking for?

5. What's the best way to insulate around the attic access panel?

6. When navigating in the attic I know it is best to use plywood but it seems like that would require a lot of plywood (I know I'd cut it in 2' strips). How think should the plywood be? How do I insulate over it?

Thanks in advance.
 
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Old 02-10-14, 06:37 AM
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Here are a few more pictures.
 
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Old 02-10-14, 08:06 AM
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Leaks through the ceiling are everywhere and all are important. The top of all walls below where the drywall is attached to the top plate is a long thin air leak. Add in all of the holes drilled for electrical and plumbing and your ceiling is swiss cheese. Imagine filling your house with water and tipping it upside down, water would pour into the attic. But your timing is correct as you will have to disturb a lot of the insulation that is up there to get this done correctly. Once you fluff it back in place then you can add more to it. When they built the house all of this would have been relatively easy.

All ducting in the attic, supply, return, or even bath and kitchen vents, need to be air sealed and insulated and preferably rigid metal.

I couldn't see what is there for attic ventilation. There should be baffles in each rafter bay to prevent insulation from filling the soffit area and blocking the air flow. There should be plenty of soffit vent area, visible from outside. And there should be a ridge vent at the peak of the roof running the full length (almost) of the ridge. Total vent area if you do a good job of air sealing is 1 sq ft of net free vent area for every 300 sq ft of attic floor, half high and half low.

The attic access should have a perimeter board higher than the insulation depth, a cofferdam of sorts.

Once done there should be little or no navigating in the attic. I have built raised platforms in some homes down the middle, high enough to get a full layer of insulation under the walk. For temporary boards I would use ¾" plywood and 8' long and leave it on edge up there for the next project. Problem is, once you increase the depth of the insulation well above the rafter height, using those boards will compress the insulation, which should remain as undisturbed as possible.

Enough for now
Bud
 
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Old 02-10-14, 09:39 AM
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There should be at least 12" of insulation up there.
Recommended Levels of Insulation : ENERGY STAR
 
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Old 02-10-14, 11:49 AM
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From appearances, I would say that your insulation is one of the light density fiberglass materials like "Insul-Safe" from Certain-Teed or "ClimatePro" from Johns Manville. These are very "fluffy"materials and will really start to lose loft when you start moving them around to do the air sealing. Since they are light density you will be compressing them when you install any rolled or batt fiberglass material which is made to a higher density than the blown in versions.

The guideline numbers Bud quoted for ventilation rates are actually for insulation with a vapor retarder. You may want to check the material you have for the potential that they added a separate vapor retarder but otherwise the rate should be 1 sq.ft. for each 150 sq. ft. of ceil. area. divided equally at eaves and ridge.

Keep in mind these rates are very general and really their effectiveness is impacted by a range of variables so don't be afraid to go to the extreme with ventilation.
 
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Old 02-11-14, 08:11 AM
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I went up in the attic again last night and it looks like there is a baffle running up between every other joist and there seems to be plenty of soffit vents. I also checked and the material on top is Certain-Teed and it is very easily compressed. Underneath the layer of certain-teed are bats of insulation with the vapor barrier facing down. I think it's going to be very difficult to do the sealing with all the pre-existing insulation.
 
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Old 02-11-14, 11:18 AM
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The soffit vents might be functional, but they also might be closed off. When you do work on your insulation, make sure that you actually have openings leading into the attic. The vinyl guy doing his job correctly does not mean the attic/roof guy did his job correctly.

Others here will also advise you that the bathroom/dryer/whatever vent you have in the soffits is a bad idea, and you should reroute it to go through the roof. They are correct, but I fail to see how very much of the moisture leaving that one vent can get sucked back into the attic when it has the whole outdoors to dissipate.
 
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Old 02-11-14, 02:19 PM
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Mike Rivers, usually the bath vent will dump moisture laden air which by its very nature is warm and will rise by natural convection into the attic via the vent openings in the eaves.

The moisture in that air is not necessarily enough to affect the whole attic but in many cases I see somewhat disastrous localized issues where it rises back into the attic. This can be limited to just a few rafter bays where the roof sheathing turns black or it can become more widespread relative to the amount of moisture produced and the severity of weather.
 
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Old 02-12-14, 05:27 AM
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Calvie,

You are the first person I have seen cite actual real world experience instead of just hypothesis. Thank you for pointing out a concrete example and giving me a reason to rerouting mine.

Michael
 
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Old 02-12-14, 05:36 AM
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Mike Rivers, 13,000 + insulation jobs opens your eyes to a lot of issues. Thanks for the compliment and I do agree the forums (not only the DIY ones ) can get bogged down with a lot of " common held hypothetical conjecture".

That being said, I am always open to new theories and circumstances that modify any "hard line thinking" about an issue.
 
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Old 02-12-14, 09:52 AM
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Thanks for the responses. So if I understand correctly, exhaust vents should actually be routed out the roof and not the side of the house, correct? Is this only for second story room vents? Are there any other options as closing a hole in the side of our house and making one in the roof is a little outside what I'm comfortable doing myself?
 
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Old 02-12-14, 10:33 AM
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I'm pretty sure most people will say that the one on the side of the house is ok. It is so far down that it won't do much to the attic.

The issue is the one in the soffit.
You do now want this.

Instead, you want this.
 
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Old 02-12-14, 11:24 AM
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PM, if there is an opportunity to vent the upper level exhaust port through a gable end wall, do that. As long as you have an end wall and the pipe run isn't too far that would actually be better than the roof.
 
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Old 02-15-14, 08:51 AM
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Is it permissible to vent a bathroom out the gable end? I ask for I'm adding a full bathroom to the second floor of my 1840's story and half farm house. I have a raised seam metal roof so I'd rather not upset it. Plus, I'd have to hire a contractor to do that for me. Thanks, Roger
 
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Old 02-26-14, 03:34 PM
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vent

I personally wouldn't go through the trouble of running the vent through the wall and out the roof since the structure is already existing. You can run into a lot of problems that way. We have had to run the vent on the outside on several occasions, and we just boxed it in so it didn't look bad. You can even route it around the soffit, but I would just shoot it through. As long as it is flashed correcty, it looks a lot better when just shot through the overhang. It isn't hard to flash it either - just use the proper roof jack for it.

I think I understood the question correctly. If not, I do apologize for the misunderstanding.
 
 

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