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OhmZoned 10-30-2011 10:47 AM

Help with complicated insulation project in attic
 
Hi Everyone,
I am working on a whole house insulation project since my current house is FREEZING cold in the winter. I have renovated the interior of the house myself, so I would say I am pretty handy. I could however use some advice on how to best insulate some other spots in my house.

The first major area of concern is the attic. I have basically 3 "spaces" in the attic that need help.

The first space is the attic over the original house. There are 2x6 joists with 3/4 plywood running across them to form a storage area. Under this plywood is the original fiberglass batting. There is a kraft paper vapor barrier facing up. The insulation has been compressed over the years and is no more than 1" in most spots. I have found that the person who laid the plywood decking did not notch out the joists where the wires crossed, so I have old wiring that is pinched between the attic decking and the joists. I will be removing all of the decking since I do not need storage in the attic. I will close all of the open junction boxes, then install rafter vents and either 20" (r-60) blown in Atticat insulation or unfaced insulation on top of the existing insulation, then another layer perpendicular.

https://lh3.googleusercontent.com/-J...rt%2525201.jpg

The second "space" in the attic is basically the same layout as the first (2x6 joists with 1" old fiberglass insulation). However on this side, the ceiling of the master bath sticks up through the attic floor. I have some issues in this area that need to be addressed. First is the fact that there are non-IC rated recessed lights which are covered in insulation. I was going to build a box around these with either sheetrock or foil faced insulation, but I have decided to replace these lights instead. I can currently only get to 2 of 8 from the attic. The other 6 lights are part of the third "space" in my attic which I will get to in a minute. In this area of the attic there are a lot of open electric junction boxes where the lights for the bathroom were tied in. I am going to have to close these as well once I get the lights rewired. My idea here is to replace all of the lights with IC rated, air sealed lights. Then I will air seal around them and insulate the entire thing with 20" of blown in Atticat insulation. On this side of the attic, there seems to be about 6-8" of blown in cellulose. However it is not correctly spread out, it is just thrown about. I am considering bagging it up into contractor bags and just blowing down new atticat insulation.

https://lh6.googleusercontent.com/-O...ic%2525202.jpg

The third "space" in the attic is the strange one. It is actually the old roof of the original house which creates a space in between the old house and the addition.

https://lh3.googleusercontent.com/-M...ic%2525203.jpg

The space is COLD. I was thinking that I should fill this entire space with atticat insulation. First I would seal any holes along the master bedroom wall, which happens to be insulated (for the most part). I also have to replace 6 more non-IC rated lights at the end of this space in the master bath. Can someone help suggest what to do in this area? The master bedroom is an addition that is insulated (mostly). The back wall of the master is about 13' high, the top 4 feet of the wall is this "space" in the attic. My thought is that if I fill it with insulation, it might help keep the master bedroom warm.

Any helps, tips, thoughts, suggestions would be very welcome. I am going to make this house warm - it must happen!
Thanks so much - looking forward to the conversations this may spark.

Ohm

oh'mike 10-30-2011 03:37 PM

No one jumped on this one---that attic space with the old roof looks like a royal pain---

Check those can lights---if they say IC (insulation contact) you are good to go---just insulate them.

That old roof---you should be able to cut out sections of the old roof deck to give you better access to insulate the walls----the insulation in the attic below the shingles should be enough to keep the cold out of the house --if you insulate the exposed walls.

Windows on Wash 10-30-2011 03:56 PM

Air seal all accessible points prior to blowing in your insulation (i.e. top plates, penetrations, wiring, plumbing vents, etc, etc.).

No need to remove the lights in lieu of IC rated lights. Just create enclosures around them out of drywall and be done with it. Seal them to the floor as well.

You can spray foam those vertical walls if you want of just fill that cavity.

Removing the old roof, as oh'mike mentioned, might give you better access.

OhmZoned 10-31-2011 01:39 PM

Reply to tips
 
Thanks for the feedback. I agree, this is going to be a total PAIN! I have a few comments:

"Just create enclosures around them out of drywall and be done with it." Well, the problem here is 2 fold. First, I can only get to 2 of the 8 lights to even consider building a drywall box. Also, I heard that you should not do this because the top of the box won't provide enough air\venting for the lights and it again becomes a fire hazard. These lights are NON-IC rated, so I think replacing them is going to be my best bet. I am thinking that maybe the way I should go is to just see if I can retro-fit 8 of the lights from inside the master bath, not from the attic(s).

That old roof---you should be able to cut out sections of the old roof deck to give you better access to insulate the walls
I have been able to cut out sections, that is how I even got up there to take the photos. I found a leak up there as well which I will need to seal. Unfortunately, I don't think I am going to be able to get to the walls here, so I may still just go with dumping insulation across the old roof and air seal what I can. I had considered doing a DIY sprayfoam kit (tigerfoam or similar), but I don't think it will be warm enough up in the attic by the time I get to it. I live near Philadelphia, and we already had a snow storm (though a bit freakish even by our standards).

Windows on Wash 10-31-2011 07:10 PM

See responses below. Good luck.

Quote:

Originally Posted by OhmZoned (Post 760839)
Thanks for the feedback. I agree, this is going to be a total PAIN! I have a few comments:

"Just create enclosures around them out of drywall and be done with it." Well, the problem here is 2 fold. First, I can only get to 2 of the 8 lights to even consider building a drywall box. Also, I heard that you should not do this because the top of the box won't provide enough air\venting for the lights and it again becomes a fire hazard. These lights are NON-IC rated, so I think replacing them is going to be my best bet. I am thinking that maybe the way I should go is to just see if I can retro-fit 8 of the lights from inside the master bath, not from the attic(s).

Not venting the lights does not cause them to overload. Only in situations where you have very hot (i.e. halogen) burning lights do enclosures create overheating and overloading issues. IC rated can lights are sealed up already with much less air space and do not overload/overheat when you run the allowed bulb.

If you can replace them with IC rated fixtures and don't mind the added expense, do that and caulk them to the ceiling. Best of both worlds.


That old roof---you should be able to cut out sections of the old roof deck to give you better access to insulate the walls
I have been able to cut out sections, that is how I even got up there to take the photos. I found a leak up there as well which I will need to seal. Unfortunately, I don't think I am going to be able to get to the walls here, so I may still just go with dumping insulation across the old roof and air seal what I can. I had considered doing a DIY sprayfoam kit (tigerfoam or similar), but I don't think it will be warm enough up in the attic by the time I get to it. I live near Philadelphia, and we already had a snow storm (though a bit freakish even by our standards).

No issues with the foam. Keep it in the home prior to going into the attic and you can easily put a space heater next to it to get it up to temp. The warmer, within reason, that it is, the better it goes down.


OhmZoned 11-04-2011 09:50 PM

I am now thinking that I will replace all 8 lights in the bathroom with new IC rated lights. They are currently halogen and they make me nervous, especially since I know they are in a very humid area. Are there air sealed ic-rated retro 3" lights that I can use to replace them? Let's pretend that I cannot access them from the attic. Do you just pull the old ones out and rewire? Should I put in 4" recessed cans to hold a cfl instead?

Once I get IC rated lights, I am going to air seal as much as I can and then just blow in Atticat insulation over the old attic and the old roof in the "other" attic.

Ohm

OhmZoned 11-13-2011 09:27 AM

Yesterday I replaced all 8 lights with IC rated, airtight cans. So now I can airseal and then insulate. The insulation gets more complicated the more I read...


I read this article and it seems like blown in fiberglass loses its R-value because it is low density and allows convective loops. The article seems to suggest using cellulose instead since it is higher density.

My other option is to install fiberglass batts - I do not plan on putting anything on top of them, once my attic is reinsulated I do not plan on using it for any storage. According to the information Gary posted:

All the ones (low density) listed without a HD (High Density) will have inherent convective loops in a wall or attic floor installation.

R-13 HD*at*1.0# density*
R-19 at 0.55# density*
R-21 HD*at*0.90# density*
R-30 at 0.57# density*
R-38 at 0.53# density

I am trying to get to R-60 in my attic. I live near Philadelphia, so I know R-60 is overkill, but the winters are getting worse, and I am always cold, so I figure - if I am going to do it, do it right. My attic is currently a combination of old fiber glass in spots, topped with some loose fill cellulose (at least thatís what I have identified it as) in spots.

http://www.diychatroom.com/members/o...-cellulose.jpg

My plan of attack is something like this:
1. Replace non-IC rated lights with IC cans. Done!
2. Spread old cellulose a bit more evenly, as you can see from the photo it is piled up from when the bathroom was remodeled (this is where you see the yellow fiberglass batts).
3. Air seal as many leaks\lights\wires\etc. as I can find.
4. Install styrofoam baffle vents along the soffits
5. Insulate.

With the extra information I have read this morning, it seems like the Atticat blown-in fiberglass insulation is low density and therefore will lose R-value because of convection loops. Is this only if it is overblown (which it seems to be in most cases)? Should I then use cellulose instead? It is almost twice as expensive, but if it helps keep the house warmer, I am ok with spending the extra money. I currently have some old fiberglass insulation which I would be putting cellulose on top of to complete the job. With the cellulose, does it have to be blown in, or can it be spread by hand?

If I were to use the R-21 batts (since they are HD), could I just stack 3 of them perpendicular to each other to achieve the R-60 I am looking to get? I will not be compressing them under any wood or anything, only other layers of insulation. Should I put a layer of housewrap on top of them? Would I just use Tyvek? Or spread 2" of cellulose on top of the fiberglass as suggested to prevent convective loops, or is this not necessary because they are HD?

I am going to be removing the floor boards in the attic - so unless I remove all of the old fiberglass and cellulose, I will just be insulating on top (unless it is suggested to remove, in which case I will do as suggested).

If someone wants to just make a blanket "if it were me, I would do this" statement that may help direct me. I really appreciate all of the research and information. I am trying to comprehend what I can, but there is so much information it gets a bit overwhelming!

Thanks for the help - redoing the recessed lights was a major milestone. The next step is air sealing, which needs to be done no matter what type of insulation I use it seems. Now I just need to get a better grasp of some of this convection science.

Michael Thomas 11-13-2011 09:42 AM

2 Attachment(s)
1) Is this just scrap PVC pipe, or did someone leave an unterminated vent in the attic?

2) Are are the struts carrying the roof load down to a work load bearing wall, or are they just bearing on unsupported portions of the joist span, and potentially deflecting downwards?

Windows on Wash 11-14-2011 09:45 AM

Don't remove the batts or anything else.

Blow with cellulose. There is not comparison from a worker safety or performance standpoint.

Make sure you include sealing top plates in that set of prescriptive repairs.

OhmZoned 11-14-2011 10:00 AM

I have to check if those are load bearing struts. I think they may be, there is a wall below them. The PVC pipe is just scrap, but thank you VERY much for keeping an eye out!

It is starting to sound like cellulose is my best option. I will calculate what R-60 cellulose takes then to do my attic. There is a cavity at the end of the walls which drops about 24" into the rooms below. Currently there are old fiberglass batts in these cavities. Should I remove these and air seal what I can, then blow in cellulose below?

http://www.diychatroom.com/members/o...-end-batts.jpg

Do I need to rent the machine for blowing in cellulose, or can it be spread by hand\rake?

Thanks!

Windows on Wash 11-14-2011 11:05 AM

The the wall that is hollow is between two conditioned spaces, just put in rigid blockers, spray foam them for air tightness, and blower cellulose overtop. No need to insulated between conditioned spaces unless you are worried about noise.

R-60 in cellulose is going to be about 16-17" in total but you do have some insulation up there already.

OhmZoned 11-14-2011 02:18 PM

Quote:

Originally Posted by Windows on Wash (Post 770912)
The the wall that is hollow is between two conditioned spaces, just put in rigid blockers, spray foam them for air tightness, and blower cellulose overtop. No need to insulated between conditioned spaces unless you are worried about noise.

The wall that has the cavities is an exterior wall. It connects to a bedroom below, and the soon to be insulated attic above. There is currently fiberglass in there, should I pull it and put in something better? I can see down the edge about 20", but I don't think I could get a can of spray foam in there with rigid insulation to air seal.

OhmZoned 11-19-2011 08:49 AM

On the other side of this wall is the bedroom. What you can see in the photo is the top 4' or so of the bedroom wall.

http://www.diychatroom.com/members/o...14-bedwall.jpg

For this wall, should I pull out the fiberglass and put in rigid insulation, spray foamed around the edges to better insulate and airseal?

If I am using rigid insulation, do I have to cover it with drywall or something that is fire resistant, or foil faced rigid insulation? Or can I just use the pink foam insulation? No one will be in this area once it has been insulated.

Once it has been "sealed," I am going to be filling this part of the attic with cellulose. I will also be insulating the space under the "old roof."

http://www.diychatroom.com/members/o...pace-attic.jpg


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