Hi there,

Your website is awesome and super helpful. I am trying to decide whether this is a job I can do myself or one I need to call a professional for.

I am looking to add R-30 or R-38 to my attic. It is a 1600 square foot ranch with a low roof. I have a few questions about it if you have the time.

1. Am I better off getting insulation blown in or laying batts/rolls?

2. Could you give me a rough price estimate for both? If I am going to do it myself I also have a few different questions

3. I will probably lay batts down if I do it on my own, I have read that they always go perpendicular to the floor joist. Is this always the case?

4. I will be adding to the current insulation between the joists. I know I do not want a double vapor barrier, is it enough to slash the kraft paper on the insulation or am I better removing it all together? I would just buy unfaced but the faced is so much cheaper.

5. Is there any easy way to move around when you're climbing around on the joists up in the attic? I do not have a big enough hole to bring plywood or anything like that up there to walk on,

I was wondering if maybe there are some tricks of the trade.

Thank you very much,

Question #2:

One more question for you.

You suggested blown in fiberglass. If I were to do it myself, am I better off doing that than laying Batts? My only concern is the small space I have to work up there and what would seem to be inconsistency in the Heights of the blown insulation in different parts of the attic based on the way it comes out of the machine.

Are either the Batts or the blown better or more effective?



Hello Josh,

In answer to your questions:

Due to the fact that you have limited height in your attic, I would strongly suggest that you have blown-in fiberglass installed.  It is very important to make sure that the contractor installs air baffles, air chutes or proper vents in every joist space for ventilation.

Another advantage to having it blown-in would be for a minimum up-charge you can add additional insulation trying to achieve a maximum of R-49, which is the point of diminishing returns

The cost to do it yourself is about a third of the cost of having it done professionally, but the savings do not warrant the risk that you are taking by being in a low attic and the expenditure of a lot of your time. 

If you decide to do it yourself and not buy unfaced insulation, I would recommend that you remove the paper totally.  You will find that the paper removes better one way or the other without taking a lot of the insulation at the same time.  Normally you would have to open the roll of insulation up all the way and start from the end separating the insulation from the paper backing.  The insulation is sprayed with glue as it rolls down an assembly line therefore it will peel easier the opposite way it came down the line.

Yes, lay the insulation batts perpendicular to the joists if you are installing it yourself and be careful not to block off the eaves and remember to install air chutes in each rafter space.  

As far as the price difference I would recommend you get 3 estimates in the town where you live and do not take the lowest one.

Hope this helps and thank you for the compliment on my website.

Bruce Jones
The Insulation Doctor

Answer to Question #2:

The fiberglass blown-in is just as effective as the batt insulation.  However, you will need more inches to achieve the equal R-value as the batts.  

My concern with you trying to blow it yourself is first of all I doubt that you can get in far enough to install the air chutes at the ends of every rafter space due to the low attic space. 

Second, most people think they are blowing 8" and buy enough material to cover the area with 8" and end up blowing 10" to 11" because the insulation comes out of the machine faster than they anticipate and then are forced to purchase more insulation.  The reason this happens is that there is a learning curve to installing blown-in insulation.  The simplest way to describe it is you have a machine strong enough to blow the insulation like it is snowing in your attic not direct like you have a fire hose in the attic. 

Another disadvantage of doing it yourself is the risk of stepping through the attic drywall at some point causing you a major repair to the drywall, repainting the ceiling and possibly some harm to yourself.  If a contractor was to have this problem his insurance company would handle the repairs and you would not be faced with deciding whether to pay the deductible on your insurance along with having a major claim.

I would recommend that you have a local contractor install the blown-in insulation.

Bruce Jones
The Insulation Doctor