Insulation Help

[MEMPHIS91]

Howdy guys I got a couple insulation questions/approval.
First is my question is about my chimney, using my seek geothermal I found that behind my brick in the center an entire brick wall is NOT insulated at all.
The chimney is behind the wall with a 12" gap. Left and right sides have insulation its just the center part that doesn't.


So my idea is to dump 16 cu ft of perlite in this hole , this sits right above the main fire and in between the main brick wall the the chimney so there is a good bit of heat here, then thermal/radiant barrier, then just blow in fiberglass above that. The perlite holds heat very well and has an R value of 3 per inch.
Has this ever been done? Or am I just crazy?

Next is the joist between my upstairs dog house bathroom and the laundry room. During the blower door test I found huge air leaks in that area, so I starting taking things apart found that there are HUGE gaps in the eve. Follow the pictures to see the area I am talking about.




I was thinking about jamming some fiber glass as deep as I can with my arm and then going crazy with some spray foam on top on it? There are 7 of the joist gaps.

Good news is that I got a lot of double bubble radiant barrier up on the knee wall of my vaulted ceiling, and some single layer on the rafters.

[Ron342]

On the chimney, I've seen chimneys insulated with mineral wool right up against the brick then fiberglass or cellulose outside that layer. Don't know what what the fire rating of perlite is but it is a mess in that the finer parts sift down into tiny cracks in your wall (think Elec boxes)
On the soffit , sounds fine unless it's part or all of the soffit venting system.
I've seen mildew in baths which had bubble wrap - I think it has zero moisture transmission.

[MEMPHIS91]

Doax you mind changing this thread title to "MEMPHIS's Home Insulation Project"?

So I was able to use 6 cans of spray foam and some insulation board to patch the holes in the eves of the house.

The chimney is in no way a part of the soffits so I used 2 big bags of perlite.

But haven't added the other insulation on top yet. (Gonna have my guy just blow it when he does the rest)
But this picture shows that the area about the heater (about 3.5 feet) is staying MUCH warmer. And even after a fire is out for hours it stays over 100F. I just took this picture. I put wood on the fire at 5:30am it is now 8:30pm and its still 95F

Tons of knee/back breaking work and I got all the ceiling joist sealed up that run under the upstairs floor, there were about 25 of these that just had a very little amount of insulation loosely covering half of the hole.


Found huge holes like this that where letting in air and pest. That got foamed as well.

Then there was the 6 feet of insulation that I could (barely) get to the is at the bottom of the vaulted ceiling. It is just 6" batts that had all kinds of mouse holes and air tunnels that extended all the way to the top of the vault. Meaning cold/hot air was reaching the sheet rock. There was even frost on the back of the sheet rock in some places. So everything got spray foamed to stop up mouse holes and air tunnels then more double bubble radiant barrier and finally more single layer radiant barrier on the rafters. I was sore for days after this. GLAD its over.




More coming soon!

[nibs]

Chiming in a little late here, but the space behind the chimney would lend itself to styro-crete. Ground up styrofoam entrained in concrete.
I did that behind my fireplace and it seems to be working very well.
We are putting in a rock & cement wall above the hearth which we want to heat up from the exhaust gases, behind that is a styrocrete wall about 8" thick so that we minimize heat transfer to the exterior wall.
Styro or EPS crete stays where it is put, does not compress or shrink is termite and fire proof and easy to do.