# Help with complicated insulation project in attic



## oh'mike (Sep 18, 2009)

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.


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## Windows on Wash (Aug 30, 2011)

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.


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## OhmZoned (Oct 30, 2011)

*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).


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## Windows on Wash (Aug 30, 2011)

See responses below. Good luck.



OhmZoned said:


> 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).
> 
> ...


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## OhmZoned (Oct 30, 2011)

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


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## OhmZoned (Oct 30, 2011)

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 that’s what I have identified it as) in spots. 










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.


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## Michael Thomas (Jan 27, 2008)

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?


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## Windows on Wash (Aug 30, 2011)

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.


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## OhmZoned (Oct 30, 2011)

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? 










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

Thanks!


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## Windows on Wash (Aug 30, 2011)

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.


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## OhmZoned (Oct 30, 2011)

Windows on Wash said:


> 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.


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## OhmZoned (Oct 30, 2011)

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. 










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."


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