Attic Insulation: DIY or Pay?

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Forum topic by Rayne posted 07-07-2016 01:58 AM 1407 views 0 times favorited 19 replies Add to Favorites Watch
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1062 posts in 1686 days

07-07-2016 01:58 AM

Topic tags/keywords: tip question resource

Hello All, I’ve tried looking for an answer on this in many places. It seems like it would be an easy answer, but I have some concerns. Would you do your own Attic Insulation using a blower rental or pay to have someone else do it?

I’m all for doing it on my own, but my 1st concern is that it would take a lot of work to create a “barrier” next to the perimeter vents so as to not block it with the blown-in insulation. Any ideas to make this easier?

2nd concern. There is an attic entrance as well as some “flooring” I installed around the entrance so I have a place to store some seasonal items. Would batt insulation be o.k. for this and then cover it back up with the flooring and just have the remaining space be the blown-in?

I really need this so I can kind of work during the summer where it’s just unbearable in the garage. I can only stay in there for 5 minutes before I’m sweating like a faucet, so I definitely need to get this done. I’d appreciate any ideas/suggestions/opinions on this. Thanks!

19 replies so far

View DirtyMike's profile


637 posts in 1049 days

#1 posted 07-07-2016 02:15 AM

Diy for sure. There are cardboard barriers and other venting aids that keep your soffit vents free of any insulation.
Making your own can be done in a day with a buddy. I cant recommend cellulose over fiberglass enough. I have tried both and the cellulose seals so much better . My local family owned hardware store has it cheaper than home depot, so do some shopping around. Over estimate your insulation by 20%, you dont want to get almost done and run out. If you decide to use cellulose i highly recommend proper ppe and a very bright light. If you have air handles in the attic be sure to seal them up tight. Cover any open holes,switches, junction boxes and light fixtures with un batted fiberglass. Have a game plan before you even rent the machine,it will help. Good luck

View diverlloyd's profile


3121 posts in 2004 days

#2 posted 07-07-2016 02:16 AM

Any insulation is better then none. Blowing insulation sucks and it sucks more in the summer in a attic. It’s like doing drywall it easy and doesn’t seem like much of a hassle but after you do it you think I should have paid someone. It also takes two people to blow insulation one to man the hose and one to feed the hopper. If you do do get the blown insulation you could put the rolled down and put your makeshift flooring down. Then build a wall with insulation board and have the rest blown in. Also if you have canister lights they can’t be covered by insulation they need air space to stay cool. If you have any thing you want to get to I the attic lighting,hvac or anything like that you might want to build a walk way and more retaining walls with the insulation board. If you do it yourself think of the safety you will need to take breaks,stay hydrated, and wear a good dust make or respirator. Be safe on which ever you choose. I may also look into the expanda foam I don’t know the price difference or the cost but I have heard good things about it.

View Rayne's profile


1062 posts in 1686 days

#3 posted 07-07-2016 02:47 AM

Thanks for the quick feedback. I did completely forget about the junction boxes and open holes. I don’t believe there are any in my attic, but there are insulated, power feedlines going all over. I would guess this is not an issue since they are all insulated. I was hoping i could do this on my own, but I can see it’s just not going to work that way. Thanks again for the suggestions and it looks like I’ll be making my gameplan soon. I’m eager to get back in my garage without dying. lol.

View jonmakesthings's profile


73 posts in 965 days

#4 posted 07-07-2016 03:05 AM

If you do end up doing it yourself I would highly recommend cellulose over fiberglass, just because fiberglass sucks if you have to dig through it at all and cellulose works just as good. The downside to cellulose is it makes the air really dusty but as long as you have good PPE it’s fine. And yes, mixing batts and blow-in is perfectly fine

-- How can you have any pudding if you don't eat your meat?

View WhoMe's profile


1564 posts in 3390 days

#5 posted 07-07-2016 03:51 AM

I’m actually in the process of doing this to my house as we speak. For the soffit vents there are both plastic and cardboard/fibre pieces that staple to the roof studs to create a open area from the vents up the roof a couple feet that prevent clogging when you blow in the insulation.
I did plastic because they were cheap. What I found is that almost none of them actually fit between the roof studs properly where you can just fit and staple. And many times the ceiling studs bisect the roof studs so you have to almost cut each individually for each hole and then staple as best you can. In my case, it took about 6 hours over 2 days to complete just that as it was getting just too hot by 11 am in the attic.
Yes, remember any open junction boxes, you need to cover them. And any significant holes to the living space, fill with canned foam.
As for fiberglass vs cellulose vs foam:
blown in fiberglass is the cheapest but has the lowest R value per inch. So, it requires more to blow in.
Cellulose has much higher R valuer but is more expensive. and requires less than fiberglass for the same R value/thickness. As well as MOST cellulose has both insect and fire retardant powders in the material.
Foam is the most expensive and the most difficult to install and is generally not recommended for anything that is not new construction. not to mention, you would end up spraying the foam to your roof and not the room ceiling.
Also, if you have any existing fiberglass or blown in insulation and you want to use rolls/batts, all recommendations i see are to use unfacedrolls/batts on top of existing insulation. if there is no preexisting insulation, , then use kraft faced rolls/batts with the facing towards the room to be insulated.
All of this is from my research and is not hard fast rules.

As for me, as much as I would love to use cellulose, I think I am going to use blow in fiberglass purely on a cost basis. But I NEED to go back and look as costs versus R value. Im not a fan of the itchy side of the fiberglass if I need to go back up there for any reason. And, I’m stubborn so I am doing it myself.

-- I'm not clumsy.. It's just the floor hates me, the tables and chairs are bullies, the wall gets in the way AAANNNDDD table saws BITE my fingers!!!.. - Mike -

View bondogaposis's profile


4993 posts in 2498 days

#6 posted 07-07-2016 04:03 AM

I was going to do mine myself and figured out the cost of insulation and blower rental. Then I asked an insulation company to give me a bid and the contractor came in $100 cheaper than I could do it myself. So that was a no brainer. I think the savings comes from the company buying insulation in wholesale quantities and of course they don’t have to rent the equipment. It pays to check around and figure it both ways, I was quite surprised.

-- Bondo Gaposis

View Greg the Cajun Wood Artist's profile

Greg the Cajun Wood Artist

441 posts in 1089 days

#7 posted 07-07-2016 04:04 AM

I had foam insulation sprayed in my shop and it was the best decision for keeping it comfortable. Sure, it initially cost more than other insulation and is far superior but well worth it. A single window A/C keeps my 24×40 shop cold during the 100 degree weather we have been having recently

-- Wood for projects is like a good Fart..."better when you cut it yourself"

View Kelly's profile


2092 posts in 3091 days

#8 posted 07-07-2016 06:47 AM

I’ve done a couple and used the baffles they sell for a buck or two a pop. They make keeping the blow-in off the outside vent areas a breeze. they work for my glass insulation in the shop too.

Home Depot let me have the blower free, if I bought twenty bags. Twenty bags was no big deal, even though it was raining. I kept the bags in my Twinkie Mobil (Grumman step van) and brought the hose in through a vent.

Keep in mind, this was a house I was renting, but I figured the electric savings made dropping a few hundred to cut the bill was worth it.

View Dave G's profile

Dave G

332 posts in 2195 days

#9 posted 07-07-2016 09:50 AM

Just a reminder. It takes just a few minutes to roll out a huge amount of fiberglass roll. I did that in the attic. 2 hour job total. I’ve used the cellulose. Perfect for finished walls. I’m not so sure about the attic. Harder to rearrange later than the rolled batts.

-- Dave, New England - “We are made to persist. that's how we find out who we are.” ― Tobias Wolff

View rwe2156's profile


3092 posts in 1627 days

#10 posted 07-07-2016 10:00 AM

Get a couple quotes. You’ll very like find out what bondo did. When we built an addition on our house, same thing: the cost of the insulation was just a little more than having it installed.

-- Everything is a prototype thats why its one of a kind!!

View dhazelton's profile


2789 posts in 2443 days

#11 posted 07-07-2016 10:10 AM

Buy a roll of window screening and staple it in place to keep the insulation out of the eaves.

Cellulose will compress a lot over time and you lose some r value there. Lowes used to return the price of the blower rental if you bought more than $200 worth of cellulose bales.

View jdh122's profile


1039 posts in 2964 days

#12 posted 07-07-2016 10:51 AM

I added about 10 inches of cellulose to my attic over top of the fiberglass that was there, did it myself (with help: this is a 2 person job). It was quite easy (but very hot). If you go with hiring someone, make sure that your quote is for a given amount of insulation (a specified number of bags) rather than a given r-value or insulation thickness. I’ve heard that some insulation contractors add more air to the mix by adjusting the blower which puffs up the cellulose but does not give you the stated r-value.

-- Jeremy, in the Acadian forests

View JBrow's profile


1366 posts in 1067 days

#13 posted 07-07-2016 04:15 PM


I am with Dave G and in my case I rolled out fiberglass bats over my garage workshop. I have done the do-it-your blown-in my past and probably will never do it again or recommend it to anyone.

I added one layer of unfaced R-19 fiberglass (or other insulating material) bats pre-cut in 8’ lengths over my garage workshop. I used a long pole to ensure the bats reached and covered the exterior perimeter walls (trying to avoid ice dam problems) while ensuring soffit airflow. In areas where I walk when working in the attic and around the attic scuttle hole, I cut the bats to 4’ lengths, making them easy to move. When I enter the attic to do work, I move the 4’ bats out of the way and roll up (rather than moving) the 8’ bats to expose the work area. It is a simple matter to replace the insulation when I am done in the attic. If you went this way, two layers of R-19 arranged perpendicular (if practical) or simple stacked one bat atop the other would work; or a thicker bat could be used. If you went with one layer of R-19, a second layer could be added later if needed.

The reasons I dislike blown-in insulation are…

The prep work you mention to maintain airflow requires crawling in the attic to the outer walls where roofing nails always find their mark on my bald head. This is not so much a problem if the roof pitch is around 12/12. The eve prep work takes a lot of time and moving from one bay to another is difficult at best. If the roof is framed with trusses, this job is that much more difficult. A contractor who would do the prep work would seem to be an easy out, but with the job being so difficult, I wonder whether the contractor would protect the soffits the way I would want it done.

As already mentioned, it is best done with a helper who can keep the hopper loaded. From time to time the insulation may stop flowing which required me to leave the attic to solve the problem. And it was an extremely uncomfortable job. The filter mask easily plugs and the safety glasses must be cleaned often. I threw away my long sleeved shirt and long pants when I was done, wanting to avoid contaminating the washer and dryer with fiberglass. After several showers the itching seemed to abate.

I hate working in the attic but it seems someone (usually me) is always in the attic running a cable, pipe, splicing or adding a circuit, or something else. This normally means that the blown-in insulation gets moved around or compressed. While it not a big deal to re-fluff and move around blow in insulation, doing so kicks up a lot of insulation in the air, gets all over me, and takes some time. And for some reason, bits and pieces of the blown-in insulation end up on the floor near the scuttle hole, just more to clean up.

When working in the attic that has blown-in insulation, keeping track of your tools and supplies is difficult. When I drop something and it disappears into insulation I can sometimes find it (after 15 minutes of fishing around), but I have a new screw driver still up there.

In the end, whichever way you go, the added insulation will make a huge difference, especially if the garage door is also insulated. It for sure is a project well worth the undertaking.

View Rayne's profile


1062 posts in 1686 days

#14 posted 07-09-2016 03:27 AM

Thanks for all the additional suggestions. I think I will look for an insulation company and see what kind of bids I can get. Maybe I’ll get lucky and come at or near cost of doing it on my own. It seems there are both pros and cons to blown-in vs batts, but honestly, there’s really nothing above my garage beyond a few cables. The major cables running from the breaker to the rest of the home are near my attic entrance, so I’ll be putting batt around there anyways since I installed some attic flooring for storage purposes. I guess I’ll have to do that first before I proceed with the rest of the attic. I’ve learned a lot and this will help me make an informed decision. I’ll reply back when the work starts.

View bigblockyeti's profile


5228 posts in 1867 days

#15 posted 07-09-2016 03:41 AM

I have 2×12s for the floor joists in my attic so it has R38 batts with cellulose blown in over top and cardboard barriers for the soffit vents. It works fantastic, I can keep the whole area cooler than a polar bear’s toenails if the A/C is cranked.

-- "Lack of effort will result in failure with amazing predictability" - Me

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