Blown attic insulation?

[DUNEFLYER]

I am adding blown attic insulation over existing roll/batt material.
Which material allows the Least amount of airflow thru the insulation?

Thanks for any info

 

[4Waters]

Subscribed

 

[Wedgy]

MILEX 2.0 https://www.miloinsulation.com/

 

[monkeyswrench]

It may be tough to find the Milex in your area, depending on where you are. In my area, there are primarily two different cellulose based options for going over bats. The normal "fluffy" one we have all seen, and a "wet spray"...same thing, but applied with water. Think spray paint meets spit wad. I don't know of the R value.
Another option would be to spray foam the rafters above...insulating the attic. That seems to work really well, as now your ac ducting is routed through a cooler location as well. That depends on the ability of the applicator and the design of the house though.

 

[WhatExit?]

I've been interested in re-insulating our attic but I'd like to know more on options and costs. The house seems to have mostly blown in but it could be 22 years old.

Do they remove the insulation or just blow in new over the old?

Spraying the underside of the roof sounds effective and expensive - is that commonly done instead of blowing in new insulation?

@HOOTER SLED- I'm waiting for your input

 

[HOOTER SLED-]

I've been interested in re-insulating our attic but I'd like to know more on options and costs. The house seems to have mostly blown in but it could be 22 years old.

Do they remove the insulation or just blow in new over the old?

Spraying the underside of the roof sounds effective and expensive - is that commonly done instead of blowing in new insulation?

@HOOTER SLED- I'm waiting for your input

I am interested as well.....I have blown in my attic, but was just thinking about it this week.....adding rolled to the topside under the roof.

 

[Justfishing]

The milo looked like foam peanuts. Seems like convection would be a problem.

You wont get air sealing from a blown insulation but of the 3 cellulose would be the best.

Insulation works by trapping air. The pellet structure of the milo concerns me. Cellulose needs to be installed based on the coverage rate per the bag. It can be overfluffed which will result in lower r value and more settling. Some settling is normal and actually beneficial.

Do a little research on air leaks between the living area and the attic. There can be some rather large opening between the house and the attic generally referred to attic bypass. Some of the bigger ones are around a fireplace, soffits and a flue. That is just a small list. Then there are countless small ones. An old home can have 15-20 air changes an hour. Decently well built can be 2-4 and very well air sealled are less than one.

 

[DUNEFLYER]

Well my problem started 24 years ago when we built the place. My game room (20’x30’) and one of the bedrooms (15x15) had a wood t&g ceiling installed. I did not drywall first so the t&g is installed to the joist. T&g does not seal very well. The pink batt insulation is laying right on top of the t&g ceiling. So after 24 years I installed 6mill plastic over existing insulation to help seal it up. I am going to blow insulation over the plastic. Has to be better than what was there..

 

[Mandelon]

I don't know where you are located, but as a contractor who does a lot of mold remediation, I would be worried about the plastic trapping moisture. It could condense on the bottom side of that plastic and once it is liquid, you have a potential for a mold problem.

I assume the T&G is not painted?

Around here the big box stores will loan you the blower unit if you buy their insulation. It is not hard to do. You can add 24" of it and that should really help.

 

[port austin pirate]

added about 6 inchs of blown in in the back of my house because it had blown in originally, very disappointed in results or lack of, personaly not a big fan of blown in as its messy if you have to work around. but its easier to install and if done right works well, or so iam told

 

[YeahYeah01]

I've been interested in re-insulating our attic but I'd like to know more on options and costs. The house seems to have mostly blown in but it could be 22 years old.

Do they remove the insulation or just blow in new over the old?

Spraying the underside of the roof sounds effective and expensive - is that commonly done instead of blowing in new insulation?

@HOOTER SLED- I'm waiting for your input

You can do either or. Just depends on your insulation condition. A lot of times it's pretty nasty from bugs and mice. It's nice to remove it, disinfect and seal up any holes. Then blow over.

Depending on access and if you have batt or blown and if you want batt or blown or can be anywhere from $2.25 to $4 Per sf.

We do about 10 of these projects per week all over socal.

 

[YeahYeah01]

I don't know where you are located, but as a contractor who does a lot of mold remediation, I would be worried about the plastic trapping moisture. It could condense on the bottom side of that plastic and once it is liquid, you have a potential for a mold problem.

I assume the T&G is not painted?

Around here the big box stores will loan you the blower unit if you buy their insulation. It is not hard to do. You can add 24" of it and that should really help.

I do mold as well and I'm thinking the same as you. I would be worried about moisture.

If it were me I would pull the Batt and add blown loose fill. It will fill the voids better and no moisture issues.

 

[Justfishing]

Well my problem started 24 years ago when we built the place. My game room (20’x30’) and one of the bedrooms (15x15) had a wood t&g ceiling installed. I did not drywall first so the t&g is installed to the joist. T&g does not seal very well. The pink batt insulation is laying right on top of the t&g ceiling. So after 24 years I installed 6mill plastic over existing insulation to help seal it up. I am going to blow insulation over the plastic. Has to be better than what was there.. View attachment 1023909 View attachment 1023910 View attachment 1023911 View attachment 1023912

You have to be careful you dont create a moisture trap. The amount of insulation above the plastic has to be at the point to not create condensation. There are vapor permable barriers that would stop air but allow moisture through.

There are moisture/vapor barriers and vapor retarders. Vapor is like a baseball and air is like a softball. You want a material that lets baseball through but not softballs

 

[HB2Havasu]

Myself and my Step Son did my 1700sf attic about 3 years ago. We purchased the fiberglass bales @ Home Depot. At that time if you purchased $600 or more they would rent you the hopper for free. Best thing I did. The 50+ year old insulation in the attic was less than 2” thick and basically useless. It’s now approx 12” thick and probably keeps the house 10F cooler in summer now. Super easy DIY project!

 

[Willie B]

… Los Angeles city had a program where you could have the blow in stuff done for free… Well a chick came to my door..,her father was the contractor…all this and she was dropdead gorgeous… She had her guys come out go up the crawlspace and shoot my attic with the blow in stuff…I can’t remember exactly what the R factor became w the blow in on top of theold layed between the ceiling joist stuff… but made a huge die…so far I very seldom have had to turn on the main AC unit…

 

[4Waters]

So how thick do you do it? Is there a point that it really isn't adding anything?

 

[Uncle Dave]

So how thick do you do it? Is there a point that it really isn't adding anything?

They fill to a specific r factor. The manufacturers supplies a measuring tool and they take snapshots of the fill to prove they delivered - Ill dig it up I have picts

Mine was actually free - first time in my life free was actually free.

All I had to do was sign that they delivered it and he got paid from some program.

 

[Uncle Dave]

… Los Angeles city had a program where you could have the blow in stuff done for free… Well a chick came to my door..,her father was the contractor…all this and she was dropdead gorgeous… She had her guys come out go up the crawlspace and shoot my attic with the blow in stuff…I can’t remember exactly what the R factor became with the blow in on top of the old layed between the ceiling joist stuff… but made a huge difference…so far I very seldom have had to turn on the main AC unit…

This was the deal I got.

 

[4Waters]

They fill to s specific r factor. The manufacturers supplies a measuring tool and they take snapshots of the fill to prove they delivered - Ill dig it up I have picts

Mine was actually free - first time in my life free was actually free.

All I had to do was sign that they delivered it and he got paid from some program.

What is the R factor for each inch or will the pic of the tool show that? I know how regular insulation is calculated per inch but I'm sure blow-in is different.

 

[Uncle Dave]

they took a bunch of these

Hows' it work - no idea personally I remodeled my house then rented it before it got warm.
House was never nicer than the day I moved out.

The guy that rented my house (including a new cool roof and all new dual panes ) tells me he almost never uses the AC he made me buy for him....great to know.

 

[4Waters]

they took a bunch of these

Hows' it work - no idea personally I remodeled my house then rented it before it got warm.
House was never nicer than the day I moved out.

The guy that rented my house (including a new cool roof and all new dual panes ) tells me he almost never uses the AC he made me buy for him....great to know.


View attachment 1024064 View attachment 1024065

Ok so basically an R factor of 3 per inch of blow-in, regular batt insulation is an R factor of 3.7 per inch, I believe spray foam insulation has an R factor of 7 per inch. Good to know, thanks for the pics.

 

[CarolynandBob]

I am a fan of the spray foam. House here in TN has about 4 in in walls and ceiling. House is quiet. Big thunderstorms and you hear them, but not very much.

We have our a/c set at 73 and my electric bill last month was $104. 1600sqft and a/c is 1.5 yrs old.

 

[DUNEFLYER]

Update:
I had “My insulation guy” out of Riverside come to my house today to blow my attic with cellulose insulation.
160 bags later I was very impressed with Jesse (the owner) and his companies work. On time, attention to detail and cleanliness was amazing. And charged as quoted. Great company to do business with.