Insulation: What can I get away with?

[notquitegto]

Let me first say, I'm being cheap here. I'm trying to finish up my garage on a very limited budget.

I live in northern Illinois and have a 22x25 garage. The walls were insulated by a previous owner with R13. The ceiling is open. The trusses are short and 2x4 material, so I'm only going to make a hatch for nominal storage of lights up top.

I plan to heat the garage with an electric heater for occasional mechanical work during the winter.

So, what's the minimum here? R30?. Should I go with a lower R value and spend more on a quality window? Should I use kraft paper batts? Unfaced with plastic barrier or unfaced with no barrier?

Yes, I have seached previous posts and am looking for some info more specific for my needs.

Thanks,
Mike

 

[nate379]

You talking about the ceiling??

14-18" of blow in will work nice.

 

[notquitegto]

You talking about the ceiling??

14-18" of blow in will work nice.

Yes, I'm talking about the ceiling. However, I don't know how to block off the soffit vents. With the way the trusses come together at the corners, I'm not sure I could block them off.

Mike

 

[cheap bastard]

There are styrofoam soffet vent ducts with a flap to sheild the soffets. Sheet plastic could be used on the cheap with some foam board and staples. Since you're in northern Il., check out the Rockford CL. Often the materials section has partial rolls of plastic sheet at reasonable pricing.

 

[Rosco]

Here is how I am doing my bonus room. Blocking the soffit from the insulation but it still vents behind the styrofoam board.

 

[elav]

When I was redoing my house I insulated the roof first, then the walls and then the windows. Only the roof insulation made a real difference.

 

[gumbudah]

I'd worry about the ceiling rather than a quality window.
If your ceiling is bare, probably putting up batt insulation would be the cheapest. If you're only worried about periodic winter maintenance work R30 is probably more than you need.
If you've got a shallow pitch roof and no desire to use the attic space, however it may be the same cost to put up OSB on the ceiling then blown insulation. Definitely put up a vapor barrier if you do this.
Personally, if I was in this situation, I'd first put up a vapor barrier, then put up osb, then maybe R20 worth of cellulose blown in insulation. When the budget permits, add the other R10 worth. As far as the window, cover it with plastic.