Insulating attic

Hey, Kathleen.

I'm up in Fairbanks, and I use the pink stuff, 'n so does everyone else I know. (I have two layers, which makes for an R-60 ceiling, and between that and the walls, I have one of the most fuel-efficient houses I've seen.) Just make sure there's a good vapor barrier in, and no chance for the rain or the squirrels to get at it. This insulation has been doing its thing since 1984, and looks brand new. When the installers were up there, they looked like they were wading thigh-deep in cotton candy. I cringed at that, but they fluffled it back into place nicely.

You might not need the double layer of batting for the cold, but might be worth considering to save on "air", as they called it when I was in NC.

I recently updated our insulation and I choose cellulose instead of fiberglass. Fiberglass allows for thermal loops within it, it will not stop airflow from going through it. Before insulating the attic, look for holes, cracks, etc. to seal. It's very important to airseal first. One other problem with fiberglass is the r-value decreases as temperatures drop. Cellulose doesn't allow thermal loops and the r-value stays consistent in cold weather. It's inexpensive and easy to install. It will create a continous blanket in the attic so theres no thermal bridging. After we airsealed and insulated our attic, the upstairs stays cooler in the summer than the downstairs. During the heating season, our upstairs temperatures increased 10 degrees. We went from a r 12 to r 50 and what a difference! While up there make sure there is good ventilation. We have a 1200 sq ft attic and it costs us around 600.00 total to airseal, ventilate and insulate. I'm looking forward to see the difference when winter hits.

The stuff we used is called AttiCat. It expands 16:1 and yes, it is blown in. We put in approximately 14" deep. Should work according to all I questioned about it. We also put foam in all the walls plus new windows. Bring on winter!

Have a Pro blow in Cellulose. I had a 30 by 34 ceiling in my shop done for 875 dollars, its 13 inches thick and I never did a thing except pay the bill. No way could I go to Home Depot, buy the material and blow it in for that.

A local company quoted us at 900.00 that was for insulation only. They wanted to blow in fiberglass and give us a lower r-value. For us it was worth doing it ourselves. I also rented a truck from the home depot to haul everything. Blew in 50 bags, took about 2 hours.

~*~Kathleen~*~ said:

Thanks for the input. Anybody DIY with the cellulose and can give a ballpark idea of the cost? Was it manageable labor-wise? I've an 11yo, which is often like having an extra hand, but sometimes more like dragging an extra leg around. :lol:

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I've blown in cell before. I can't remember how much it cost, but it didn't have sticker shock if i remember correctly. It is going to depend a lot on how much additional R value you want. If you buy from a big box home improvement store they'll generally let you have the blower for a day for free (around here anyway).

It is a 2 person job. One directing the hose / filling the attic and the other filling the machine. You could do it with one, you'd constantly be running down from the attic to feed the machine. No fun there. No sure if the kid would be strong enough to lift the bales into the machine....so take him/her to the store and see if they've got what it takes.

We did my last house approx 1300 sq feet of ceiling in about 4 hours, including driving 20 minutes each way, loading up at the store. Easy job.

Just make some reference marks on your roof trusses or rafters so you know how deep to get...don't want to over or under fill. Also, make sure you don't mess with your ventilation...you may need to install some rafter rents so air can move between your soffitt and ridge. You may have those in there already.

~*~Kathleen~*~ said:

Thanks for the input. Anybody DIY with the cellulose and can give a ballpark idea of the cost? Was it manageable labor-wise? I've an 11yo, which is often like having an extra hand, but sometimes more like dragging an extra leg around. :lol:

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Here its about 5-6 bucks a bail anything over 50 bails and the machine is free. Doesnt mean you cant take some back either. 800 sq ft is a cake walk. I did have a hose blow once thats really the only issue. (two bails blowing around inside the house priceless)

For 800 sq.ft a r40 would be around 50 bags and a r50 around 65 bags. When we did it the bags were 7.25 a piece. That was for green fiber at home depot. You can over the existing insulation if it's good, just airseal under it first. If it's fiberglass that's there now, the fiberglass will compress when insulation is blown on top, but cellulose will basically cap it and stop some of the air movement. Go to homedepot.com put I your zip and search for cellulose. That will give you a rough idea on the cost of insulation. I used 75 feet of hose to get into our attic and it worked okay. My wife filled the hopper while I blew it in.

~*~Kathleen~*~ said:

smokinjay said:

I did have a hose blow once thats really the only issue. (two bails blowing around inside the house priceless)

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Ah, that would have been a great one for youtube!

Okay, y'all are helping me wrap my brain about doing this. I have more time than money because it's summer. Maybe I'll throw an insulation party. I need to get up into the dreaded attic and see what's what.


There's no insulation there now. There is a recessed lighting situation I need to figure out. Don't like them.

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It is very easy and your on the right track. Just try and use one hose if possible. I shot 120 bags but I have a much larger place and the garage was empty. Took longer cleaning up the mess than it did blowing it I think. :cheese:

My father and i looked into buying the material from home depot with free machine rental, then we called a local insulation contractor he was $100 cheaper than us doing it our selves. It was approx $1600 and materials and their quote was 1495. Price it out both ways. This was blown in cellulose

I bought the fiberglass from stuff from Lowes this past winter. I have the warmest garage in town with 28 bags of the stuff just sitting there. I'm going to install my new chimney first and then do the insulation. Be careful with recessed lighting. You will have to build boxes to go around the lights or replace the units with ones that are IC rated. I am going to replace the units so I can put insulation right on top.

The paper stuff is cheap and you can rent a machine from Lowes for a small fee. The fiberglass one is free I believe but they charge like $10 bucks for the celluose one if I remember right. Go on Lowes website and they have a calculator to show how much you will need. I also stapled the vents to my roof so I can install soffit vents later. 13 might be a little young or it could be just right for crawling around the attic and shooting it in.

Cellulose in the attic is not a hard DIY job, but it is very dusty and this time of year very HOT. If you're no stranger to uncomfortable work, there's really nothing to the install, just climb around & point the nozzel/tube the right way round. The prep work is what makes a good & easy install. Definitely get all your air sealing done, deal with the recessed lights, seal & insulate the access hatch... I spent a long time up there with rigid foam, canned foam and caulk finding & sealing alot of leaks big & small. Search around & you'll find lists of the ussual air leak locations & how to seal them. There's a pretty recent thread here in the DIY forum on this too.
This is also the time to take care of any other issues you might find up there BEFORE you put down a foot or 2 of cellulose/fiberglass. Bathroom vents outleting into the attic, bad wiring...
I found a closet light wired with a nifty orange extension cord (maybe 18 gauge).

As for what depth to blow in, I say this is something you only want to do once so shoot for the DOE recomended R-Value in your region, figure a bit lower R/inch than the manufacturer states and allow for significant settling.

~*~Kathleen~*~ said:

smokinjay said:

I did have a hose blow once thats really the only issue. (two bails blowing around inside the house priceless)

Click to expand...

Ah, that would have been a great one for youtube!

Okay, y'all are helping me wrap my brain about doing this. I have more time than money because it's summer. Maybe I'll throw an insulation party. I need to get up into the dreaded attic and see what's what.


There's no insulation there now. There is a recessed lighting situation I need to figure out. Don't like them.

Click to expand...

OK. Recessed lighting could be an issue. If they're not IC rated then you can't cover them, so don't spray over them. Also, if you have any knob + tube wiring you may not want to cover that either (really old). The lights are easy enough to fix with a boot but that can get expensive depending on how many you have, sometimes as expensive as a new IC-rated can (insulation contact). This is important, and one of the most common things that can go wrong in an attic insulation job.

I've used the blow-in and the bats. As long as you get the machine for free the cellulose will be cheaper and easier. Having another person to load the bales into the blower is essential, other than that you'll be done in an hour. Even that isn't completely necessary, as you can blow it into a pile and rake/push it out, but that's a waste of time. How is your attic vented right now? What is the age of the roof? If your venting is coming from the sofitts and you're blowing in attic insulation you will need to put up attic dams to prevent choking the sofitts with insulation. Those are another expense that don't add to the r-value so what I've done and seen done is to run a course of r30+ fiberglass around the perimeter over the outside wall and under the rafters, then blow into the middle.

What kind of head room have you got? I've done it with less than 3' at the peak, where my wife was running the machine. I got stuck and she kept stuffing the machine, so I was close to being buried/asphyxiated. Only one of the times she's tried to kill me.

And I'm still here!

Sounds like that cellulose doesn't cover very much per bale.
I just did my attic about a month ago.

Had 16" in there kinda.. some places were only about 10". Filled it up to 24" (R-60) ~1400 sq ft house and 625ft garage. Took 18 bales at $24 a bale and I paid a helper $250. All I did was haul the supplys to the house and feed the machine. Rental was free for the blower (Lowe's) Cost me about $700 in total.

Took about 3 hrs and that included the 30 mins running to Lowe's to get a few more bags.

This is what I used: http://www.specjm.com/files/pdf/rig1718.pdf

I had gotten 2 bids on it by contractors, one was $1800 and the other $2000!

Dunno if I will notice a difference, I felt house was well insulated before anyhow. Heating season with the stove is about 6 months and I kept house at 75ish the whole time with less than 3 cords of wood. Was very suprised when I went up there to run wiring and realized it wasn't R45 like it was supposed to be.

As others have said, research attic airsealing (i.e. the floor of the attic, ceiling of the conditioned space), and get that done first.

So it looks like you have decent sized gable-end vents. Do you also have any "Mushroom" vents on the roof itself, or soffit vents (under the eaves)? Quite likely there are neither.
Ideal attic ventilation in a nutshell: hot air is expelled out vents high-up near the ridgeline and cooler air is drawn in lower down through the soffits. Keeps temps down and the roof a bit cooler so the shingles will last longer (you do have asphalt shingles yes?), also airflow can help prevent mold if moisture gets in there.
Lots of older roofs out there with Gable-end vents only. They are meant to expel hot air & maybe let a bit of breeze flow through. Mushroom vents can be added from above any time & are easiest when getting a new roof put on. Soffit vents would need to be prepped before the insulation job by keeping an air channel open from the soffits to above the level of insulation, usually with foam or plastic baffles pushed down to the soffit & stapled to the bottom of the deck boards. Soffit vents would then be cut from the outside. It's your judgement call whether it's worth the effort, cost is very little.
Minimum effort is to ensure that the gable-end vents are clear & open before & after insulating.

remember to keep the rafters clear of insulation...don't plug up the air flow from the soffits to the attic. buy some "proper vents" or whatever they are called in your locale...they are nothing but a cheap styrofoam channel which you stick between the rafters. then you can insulate up to and against them. keeping the air flow channel open will help the entire structure last longer with less heat and moisture buildup.
if you choose batts for the insulation material, lay down two layers...but place the top layer at right angles to the previous layer to create a better barrier.
before you do this, now is the time to change any light fixtures, exhaust fans, wiring, etc. that you have considered in the past. what about adding that ceiling fan??? you need to have a strong/re-enforced mount for the elec. connection/mount box (steel) for the fan...don't want it falling after continued use, right?
as far as the cost, check with your power supplier. last fall, i picked up some insulation when the women says, be sure to sign up for the rebate from (power company's name). not only did i receive a rebate from the ins. company, but also one from the power company, (it was developed in order to help people obtain greater energy efficiency of their dwellings), and then, once again for the rebate home improvement programs (fed and state)
hope your summer is going well

yooperdave said:

remember to keep the rafters clear of insulation...don't plug up the air flow from the soffits to the attic. buy some "proper vents" or whatever they are called in your locale...they are nothing but a cheap styrofoam channel which you stick between the rafters. then you can insulate up to and against them. keeping the air flow channel open will help the entire structure last longer with less heat and moisture buildup.

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WHy? Does she have soffit vents?. If so I agree, if not its a waste of time and money

Nobody should be using batts for the ceiling anymore. They are inferior in pretty much every way.

I also found that hiring the blowing job was cheaper than buying product and blowing it in myself. Significantly cheaper. I did all the air sealing, wiring cleanup, OTA antenna mounting, bath vent duct replacing/insulating, and soffit vent dams myself so all the pro had to do was blow.

I chose blown in fiberglass because I do not want that cellulose stuff in my attic. Lots of reasons and opinions for choosing cellulose over fiberglass and there is no right answer to that question. It comes down to your preference.

Wallyworld said:

yooperdave said:

remember to keep the rafters clear of insulation...don't plug up the air flow from the soffits to the attic. buy some "proper vents" or whatever they are called in your locale...they are nothing but a cheap styrofoam channel which you stick between the rafters. then you can insulate up to and against them. keeping the air flow channel open will help the entire structure last longer with less heat and moisture buildup.

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WHy? Does she have soffit vents?. If so I agree, if not its a waste of time and money

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my bad wally-just assumed that the structure would naturally have soffit vents..no biggie...and probably not so much a waste of money, but only a waste of time.
can't really tell if there are soffit vents or not from the pic

Highbeam said:

Nobody should be using batts for the ceiling anymore. They are inferior in pretty much every way.

I also found that hiring the blowing job was cheaper than buying product and blowing it in myself. Significantly cheaper. I did all the air sealing, wiring cleanup, OTA antenna mounting, bath vent duct replacing/insulating, and soffit vent dams myself so all the pro had to do was blow.

I chose blown in fiberglass because I do not want that cellulose stuff in my attic. Lots of reasons and opinions for choosing cellulose over fiberglass and there is no right answer to that question. It comes down to your preference.

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the reason batts are suggested is because of the available help the op has. sounds like all the work will be done by her and only her. the batts would be a heck of a lot easier to use.
the climate in n.c. is a lot more forgiving than farther north, so i think that batts would suit the need just fine. (and also, enable the job to be completed by one person, start to finish)