Attic insulation

[BigPike]

LarryRose and all, thanks for the discussion on insulating eaves. I have been getting ready to deal with this exact problem, and a google search led me to your forum.
I found the Tuff-R iso board at HomeDepot, and have a question or two on installation.
Due to the slope of the roof, access from the attic is impossible so I am tackling the problem from the outside. I have a brick/cinderblock house built in '56, and my main problem has been cold air coming in over the header board and behind the wall due to large gaps.
I had used the pink board on another part of the house and am now switching the the blue iso board.
When you are stacking the layers of board as shown in the diagram, are you:
1. doing anything to the boards, ie removing backing (TuffR has aluminum foil on both sides and Super TuffR has a facer on one side and
2. how are you sealing them in between the rafters?
I can feel the gap inside the bricks (space is too tight for me to get my fat head up there to see) and the cardboard supporting the blown in insulation is about a foot in from the header. I can feel some bx supplying my kitchen cabinet lights.
I was thinking I should try to foam the large gaps, lay the 3 boards in as shown in the diagram, with the boards on top of the cardboard in the attic (ie push back the insulation), seal the exposed edges with expanding foam, then get up in the attic and push the insulation back. I assume I should go over the top of the bx, or push it down as best I can.

The sequence of posts here have been excellent, and I appreciate any responses.

[bikin' Ed]

I need to blow insulation into my walls. The manufacturer says do it from the outside. I have 5/8 redwood siding and 1/2 in backer board. The house is a 4 level split, about 1600 sq ft. That's a lot of drilling!

Have you guys got any ideas or shortcuts?
Thanks,
Ed

[larryrose11]

Originally Posted by bikin' Ed

I need to blow insulation into my walls. The manufacturer says do it from the outside. I have 5/8 redwood siding and 1/2 in backer board. The house is a 4 level split, about 1600 sq ft. That's a lot of drilling!

Have you guys got any ideas or shortcuts?
Thanks,
Ed

Ed,
Yes, that's a lot of drilling. The 1/2 inch (cement?) backer board will destoy their hole saw bits, unless their carbide tipped. There is another option, and that is to do it from the inside. Dirtier for sure, but probably quicker, and therefore cheaper. Then there is the plaster work to go over the holes from the inside.
BTW, don't blow in Fiberglass. It doesn't perform like cellulose.
Larryrose11

[truckncycle]

I blew insulation into the interior walls surrounding the master bedroom. The walls are textured drywall which was difficult for me to match - paint helped. It was very messy. The air going in needed a place to escape and came back out into my face. I also overfilled a couple of walls and had to add a few more drywall nails. If your walls have NO insulation, this will be worth it, otherwise, it is a hassle. Wear goggles and wear a respirator. Buy or borrow some cheap walkie talkies to communicate with the person running the hopper. Don't expect them to understand you through the respirator. Tell the other person that if you key the mic two or more times it means: "SHUT IT OFF!!!". Blowing insulation into the attic on the other hand was relatively easy.

[Montana1]

I like all the great comments on improving the insulation value of the attic as I have been considering how much heat loss/gain I am experiencing in my house. I currently have blown in cellulose but I recently discovered that there is no vapor barrier between the cellulose and ceiling drywall.
To improve the R-value should I install a vapor barrier or doesn't cellulose need a vapor barrier????

[Daox]

A vapor barrier doesn't have a lot to do with actual insulation. It really is there to prevent moisture build up and mold problems.

[larryrose11]

Originally Posted by Montana1

I currently have blown in cellulose but I recently discovered that there is no vapor barrier between the cellulose and ceiling drywall.
To improve the R-value should I install a vapor barrier or doesn't cellulose need a vapor barrier????

Vapor barrier are not that common in the attic unless your in FL w/ high humidty

Mold / Mildew need a source of water to live. That is either condensation on a cold surface, or a leak. In our house, it was condensation on the walls that made mildew, and my wife and daughter are allergic. This is what lead us to foam the walls, the basement headers, and the eves (after I installed baffles, .5 inch by stud width) when we remod the exterior.

if your going to crawl around in your attic, your best bet is to seal it up from the interior of the house using great stuff foam, as posted earlier in the thread.

[mimosa]

Originally Posted by lgtech

I have an attic fan and love it. Here in NH, we only need A/C for about 10-20 days out of the year. Larryrose11 has it right... running it at night can really cool down the house if the outside temp is cool enough. I still like a direct breeze so I installed a couple of ceiling fans, too. One other thing... when you close the windows the next morning after running the attic fan, be sure to pull the window shades if you are in a sunny area. That radiation/solar heating can really add back the heat into your cooled space.

Lgtech

you can get installed solar shades for the window that absorbs the heat and control the harsh glare of sunlight.

[Runum]

Good stuff here in this old thread. Hope it's not against forum etiquette to revive old relevant threads.

I have blown in cellulose over my attic bats with great results. Also blew it in several of my rental houses with equal success. Love the stuff.

One problem I encountered...the loose stuff will blow lightly over time in the attic and clog the soffit vents and block airflow. I use a leaf blower and clean them out a couple of times a year. No need to crawl in the attic. just blow them clean from the outside in. It definitely helps keep the airflow unencumbered.

I also installed solar screens on all of my East, South, and West facing windows. These also lowered the room temps during the heat of the summer. They can be removed during the winter if desired.

[dremd]

Originally Posted by Runum

One problem I encountered...the loose stuff will blow lightly over time in the attic and clog the soffit vents and block airflow. I use a leaf blower and clean them out a couple of times a year. No need to crawl in the attic. just blow them clean from the outside in. It definitely helps keep the airflow unencumbered.
.

Maybe a box around the vents? Maybe chloroplast, or other cheap material for maintenance free operation.
Glad to hear.