Insulation

[Maine]

I plan to insulate my 28x30 garage and I have attic trusses which will become a finished room someday, but for now it is just storage. Garage will be heated with a K1 monitor heater, with a goal of keeoing it at a constant 50 degrees or so if possible.

My walls are 2x4, so I will be using R13 insulation there, with the paper covering.

The ceiling is what I am having issues with. My joists are 2x10's, and at the risk of sounding cheap buying R30 insulation to fit 24" OC truss spacing is really expensive, is it worth using R30 over say R19? From what I see R19 is half the price of the R30, which really adds up.

OSB will be used on the walls and ceiling.

Do I need a vapor barrier on the ceiling? If I do, should it be on the room side or the garage side?

I am in Maine and temps are all over the place, but the winters can be cold at times.

 

[boo coo tracks]

Nothing wrong with "Getting your bang for your buck" have you considered blown- celluose? Do the math, you could probably get R-50 for the same price as kraft faced rolls. I don't think you would regret too much insulation. Vapor barrier to the warm side.
Tracks

 

[Maine]

Thanks for the reply. The concern I have is, both sides may be heated at some point.

Blown in may work, but there is already advantech down on the second floor so it may be bothersome to insulate in that manner.

 

[boo coo tracks]

Not familar with Maine winters or your space to access. Blower can shoot ins. 10 to 20 feet which I would think would be a hell of a lot easier than rolls.
Tracks

 

[Mr.N]

From what I see R19 is half the price of the R30, which really adds up.

Question is would you rather pay more up front, or every cold month for heat? If you plan on living there for a long time, might be cheaper to pay more up front.

There are a few online articles on how much insulation to use and how much for different zones. I'd do a lot of reading on a several Google searches.

 

[NUTTSGT]

Just remember, when insulating, you're investing your money with the purchase. Insulation is something that will constantly give you a return on your money over the years.

 

[Maine]

Ok I did some research, the difference between R19 and R30 is about $25 a season in heating costs according to a study I found online.

 

[Mr.N]

only $25?
So if you figure a 7% annual increase, in 10 years you'll pay $400 more.

The Gov NRG web page calls for R49 to R60 on an Uninsulated Attic in Maine.
Yeah it's for a house, but sure makes your R19 seems low.

If it is about your budget, I'd look into blown insulation and doing it your self with a free rental from a box store.

Good read:
http://www.ornl.gov/sci/roofs+walls/insulation/ins_08.html

 

[Kevin C]

http://www.builditsolar.com/References/Calculators/HeatLoss/HeatLoss.htm

I used this calculator to figure out how much insulation to put in and where. Turns out the 10' walls were a bigger loss than I had initially figured. I'm adding a bit more to the walls.

Decent tool....

I just got in from putting up a few rolls. Amazing how much nicer the place feels as it gets insulated. I'm at the 1/2 point and I can really feel the difference.

 

[Maine]

You guys are right, blown in will be cheaper for the ceiling:

R30 roll bats = $780
R19 roll bats = $462
Blown in at R30 level = $410

The walls comes out at:

R13 roll bats: $200
Blown in at R13 level = $350

Maybe I did the math wrong but I find the wall results odd.

 

[walrus]

You guys are right, blown in will be cheaper for the ceiling:

R30 roll bats = $780
R19 roll bats = $462
Blown in at R30 level = $410

The walls comes out at:

R13 roll bats: $200
Blown in at R13 level = $350

Maybe I did the math wrong but I find the wall results odd.

Energy costs are only going to go up. If you've ever lived or worked in a well insulated space you will understand why the extra money can be worth it. The temps cross the space will be uniform, no drafts, no over by the wall is cold but over here isn't. I'd fill the space I have available and no way would I use fiberglass in the ceiling. I'd caulk every hole, crack, Pipe or wire penetration
I live in Maine also. I work outside, no way am I working in a cold shop on the weekends. I have over R 50 ceilings and over R 30 walls, worth every penny in terms of comfort

 

[Shocker]

You also need to know that the break point for diminishing returns is R19. Going from R19 to R30 only decreases heat transfer by about 2 percent.

R30 is a set standard, so a R30 15" wide roll is usually some of the cheapest insulation you can buy. Economies of scale.

 

[ixlr8]

Remember, the greatest heat loss once you put the R19 in the walls is the wood studs. If I remember correctly the R value of wood is only R-1 per inch. So the wall may have R19, but the wood stud is only R3.5 and there is a fair amount of area of wood. Putting up a layer of 1" foam board on the wall over the studs before you put up the OSB, will get you good bang for the buck. I would consider it if you are going to be there more than 5 years.