Wed Mar 06, 2013 8:32 am

I figure someone here has done their own re-insulation of the home, so I'm asking for opinions on the best methods.
Our house was built in 1995 and in the attic, the insulation was blown in. It was a gray colored, wool-looking substance that was applied nearly flush with joist. Over the years, that insulating "substance" has been disappearing with corresponding increased run time of the heat/air system and higher electric bills. So it's time to do something. I have considered buying the fiberglass bats that fit between the joist and just rolling them in on top of whats left of the other stuff, or, our local home depot has a machine for rent ,(free use if 10 bags or more purchased), for blowing the fiberglass in. That seems to be an easier way, but I have no experience using those.....I have laid in the bats, and other than making your way across open joist without falling through the ceiling, wasn't too difficult when the attic wasn't too hot. I'm hoping I don't have to remove the gray material first because that would be a monumental task. It is a single story home with a high pitched roof so there's plenty of space to walk upright. Total area would be about 1800 sq. ft. I have the common attic access under the garage which is the the pull down folding ladder. Let me know if you have experience in this and the pro's and con's if you have any.

Re: Re-insulating.

Wed Mar 06, 2013 8:57 am

Don't do the rolled insulation unless you find the kind without the moisture barrier (paper).
The last thing you need is moisture near blown insulation.

Your blown insulation is probably not "going away" but packing down. Just rent the machine and blow in another 6"-8" on top of what is there. The blown insulation will settle about 30% so if you want to end up with 6" then you put in 9" and it will settle in a year or two. Don't listen to the hype about this paying for itself in 5 years though.

Don't forget to take a look at the venting in your roof. Air needs to move up there. Most rooflines have air that enters at the soffit and leaves through a vent in the top of the roof. Don't block off the soffit - you should be able to see light coming from the soffit. Make sure there are air passageways that allow the air movement. New homes have a cardboard or foam tunnels put in to guarantee the airway does not get blocked by insulation.

Re: Re-insulating.

Wed Mar 06, 2013 9:40 am

Harold, I agree, just blow in some more insulation.

We did that at my Dad's a few years ago and it did make a lot of difference.

Re: Re-insulating.

Wed Mar 06, 2013 10:39 am

Blow in insulation or you can purchase a similar insulation in bags that is dumped out, then moved with a garden rake.

You will need to do some math to figure out the minimum amount of blown in insulation and the least expensive way to purchase it.

I did the 10 bag blown in insulation with free use of the machine. Local hardware store delivered the machine and insulation and picked up machine when we finished. Added 2 to 3 feet of insulation over what appeared to be something like horse hair. Still wound up with 2 bags left over, which I gave to a neighbor.

Used the dump out, rake it out insulation in son's attic. Floor in center of attic with uncovered ceiling joists under the eves. Only needed a couple of bags to increase the insulation depth.

Edit: Blow in insulation is a 2 person job. It's a fast way to insulate but a dirty job. The guy in the attic need to have some sort of breathing protection and a light source.

Re: Re-insulating.

Wed Mar 06, 2013 12:38 pm

When blowing it in, like has been said, more is better but too much is not good.

At the furthest reaches of the hose, when blowing it next to the eve, make sure the material is not touching the roof line. If it touches, water will condensate and you will eventually have a leak, even though the roof structure is still sound.

Just like our cubs "make water" the insulation will too if there is no airflow.

Re: Re-insulating.

Wed Mar 06, 2013 1:12 pm


Speaking from a contractor's perspective as well as my own design and building experience with my house and a friends house, it really doesn't matter what type you put in providing you have the correct safety gear to do so. Batt insulation such as Owens-Corning in the pink bag comes without any paper/foil/tyvek vapour/moisture barrier. At least it does here. Lined batts are more expensive and may be a special order or may be in stock, so choose carefully.

You should have a full tyvek suit with hood, gloves with the wrists covered and taped, full face respirator or the plastic type eye-shields and a respirator or N-95 particulate mask. This will be required whether or not you use batt fiberglass, blown in fiberglass/cellulose/fire-retardant cell-composites or one of the other new formulations.

You will also need the vent guards with the pink foam type or similar being the best. That is a must for proper air flow from the eaves. Ridge venting as a minimum is a must such as cobra vent. If you do not have cobra vent then you will have to have eve vents, roof vents, power vents or a combination of one or more systems. The blown in is kinda useful and the technology has been around for decades but is much improved. It is dangerous work though especially when it comes to your respiratory system and your eyes so precautions are an absolute must. Same as working with batt insulation although much less intrusive.

In either case, it is more than a one man job. One must be in the attic and there must be someone either feeding batts or monitoring/feeding the hopper. You may also need some form of communication, a walkie talkie or cell phone will work nicely.

Let us know what you decide.

Re: Re-insulating.

Wed Mar 06, 2013 2:05 pm

I pretty much agree with what has been posted. I did an old house with no insulation several years ago in an area you had to crawl through. The area I insulated was a little over 600 square feet, and I had to crawl in it. had to stop a couple times to change filters in my mask. Dad was on the outside feeding the machine, and I was inside with the hose blowing insulation. When I finished I looked like a big grey snow man.

Re: Re-insulating.

Wed Mar 06, 2013 3:16 pm

Thanks for the replies. Looks like blown in is the choice, however, the celluloid material, (which is what's up there already I suppose), is about 1/3 the cost of the blow in fiberglass. Is the fiberglass worth the cost/return? I got the points about the respirator and overall dust protection....and the need for someone feeding the machine. I trust the machine stays on the ground and ample hose is provided? I guess that's a question for the expert at home depot.....they have those, right? :lol:

Re: Re-insulating.

Wed Mar 06, 2013 3:31 pm


My Dad used to do work with his buddy at Cardinal Insulation decades ago. They blew in two types of insulation. One was the still typical cellulose insulation, inexpensive and has a decent R value at the beginning. This is because of the air gaps between the fibers and the individual clumps. As time goes by, cellulose insulation tends to compact and thus has a large reduction in R value as the air space/gaps disappear. So initial savings tend to become less significant as time goes by.

Fiberglass insulation does not compact as noticeably over time, in fact it usually retains it air space as long as there is no other weight applied to it. So even though the initial cost of fiberglass is more than cellulose, over time it really is the more cost effective solutions. It is the one I would choose. In fact, when I did my pole barn, I harvested some pretty nice fiberglass batt insulation and have insulated the pole barn as well as 50% of my existing wood shop with recycled fiberglass. I built my woodshop over 20 years ago and the fiberglass hadn't settled at all.

Yes, Home Depot here has all the equipment and it is on the ground and ample hose is supplied. You may need to provide the length measurement to them though.

Have fun and post a pic or 2

Re: Re-insulating.

Wed Mar 06, 2013 7:31 pm

Thanks Rudi...will do. 8)

Re: Re-insulating.

Sat Mar 09, 2013 8:35 am

Local contractor has a truck with cargo box on back set up for blowing in insulation. He has all the necessary equipment.

Probably 2 or 3 times more expensive than doing it yourself since the contractor has to pay labor and equipment costs. Might be a viable alternative to doing it yourself - depending on circumstances.

Re: Re-insulating.

Sat Mar 09, 2013 9:44 am

That was the first thing I looked into and it's expensive around here. I have a building contractor across the street who came over and looked in my attic. He echoed all the comments here and told me I could easily do it my self in one's just messy. He also said the cellulose material isn't suppose to dissipate, but he agreed that either the correct amount wasn't applied...or mine went somewhere. He also said it wouldn't hurt to put the fiberglass over the cellulose. He built his own house across from me, has about 300 sq. ft. more, and his electric bill is half of what mine is. :( So it time to do something.

Re: Re-insulating.

Sat Mar 09, 2013 11:02 am

What about the walls, what kind of insulation do they have/ also windows have a big effect on heat loss, due to air leaks around the frames, the sashes, or even through the glass. Doors have a big effect also.

Re: Re-insulating.

Sun Mar 10, 2013 12:19 pm


EJ has a good point. After you re-insulate the attic, that has to be the priority, check your bill and see what happens. It should reduces substantially. If it doesn't I would then check all of your doors and windows. It is a simple but time consuming job though - remove all the trim around the doors and windows. You will probably find that there is no insulation in the spaces where the windows/doors are shimmed. Fill this with injectable foam insulation, let cure and then re-install your trim. I would assume that your home met code at some point so probably you may have sufficient insulatiomn in the walls. 2"x4" stud walls would have R-12 and 2"x6" stud walls would have R-20. Some R-2000 homes have R-30 insulation. Blown insulation is not something that one would see in walls anymore. It used to be used but because of it's settling characteristics it was discontinued here way back in the early '70's.

As I redo the trim etc., on my windows and doors I am using foam insulation to seal the air gaps which I still have. I used fiberglass to chink those spaces but it didn't work so well. Newer products provide newer solutions to very old problems :idea: :)

Low E and Argon filled windows will lead to energy savings as well, and should be contemplated especially if your windows are more than 20 years old.

Re: Re-insulating.

Sun Mar 10, 2013 9:01 pm

Some utility companies and there are private firms that can take infra-red images of your house in winter to pinpoint energy (heat) leaks.

A winter project has been to renovate one room a winter in my son's 1940 era house. House has blown in wall insulation and upgraded windows. We strip the interior walls, re-insulate and upgrade the electrical wiring. We have found spaces where the insulation did not fill the wall space. Usually below fire breaks and over, under and directly around windows.