Insulation Help

[mcpt1]

Time to insulate my 24 x 36 garage, getting cold in MI. This will be used occasionally throughout the winter, evenings and weekends to work on my motorcycles, so I'm not keeping it heated constantly. It's a new construction stick built with the walls and ceiling still open. I don't plan on finishing the walls immediately so the insulation will be exposed for the next year or so. If I install unfaced insulation now, will I need to install a vapor barrier when I go to drywall later, or is no vapor barrier needed for a sometimes heated space. i don't want to install a faced insulation now and have the exposed , flammable paper exposed until I get around to finish the walls. Am planning to go with R 11 in the walls and R 19 in the ceiling, does that sound adequate for occasional use? I'll be heating with electric heat since running a gas line from clear around from the opposite side of the house will be cost prohibitive.
I appreciate any input
Gary

 

[Shocker]

IMHO, with the temps you will see, R30 would be a bare minimum in the ceiling. R38 would be better. Kraft faced vapor barrier would be a requirement.

It is going to be very expensive to heat that shop without proper insulation.

 

[walrus]

electric heat, R-11 and R19, wow, Electricity must be cheap in Michigan

 

[rinker1]

yes, if your using unfaced you will need a vapor barrier, plastic works well.

 

[tcianci]

I have not seen R-11 fiberglass for quite a while. I thought the minimum available for 3-1/2 inch walls was R-13. As suggested the ceiling should be anywhwere between R-30 to R-38. It all comes down to two things. 1) code minimums and 2) how much you want to spend to heat it. If you heat it rarely, then you may be able to make the argument that your payback or break-even time for using the more expensive insulation it too far out but, insulation is pretty cheap stuff and the stuff with the better R value is no harder to install than the cheaper stuff. I would use a vapor barrier before your final interior finish though.

 

[lpigg]

I guess I am going through the same problem. I am in the process of building a garage with a loft with 2x4 walls. So i can only insulate so much, right? Do I insulate the ceiling of the main floor or just the roof of the loft? I know in Illinois it is way cheaper to run a gas line than it is to heat with electricty.

 

[tcianci]

You insulate whatever space you plan on heating or cooling. If you aren't going to heat or cool the loft, create your thermal envelope with insulation at the ceiling plane.

 

[redsky49]

While more insulation never hurts, some posters on this board often overstate its importance.

The insulation transmission value (known as the U value) for R-11 fiberglass is 0.09, while the corresponding value R-13 is 0.08. Not much of a difference. Even R-19 is only 0.05.

Insulation is important for energy savings, but it is only one factor in ensuring economic operation of any space or building. Plus, all the components of the wall or roof assembly (gyp.board, siding, sheathing, etc.) contribute to the overall insulating value

Along with insulation, provide quality windows and doors. Ensure that the building is sealed properly against infiltration.

Orient your building to optimize/minimize the effects of local prevailing winds, solar orientation, lighting, etc.

In other words, try to look at the big picture, not just what you might try to cram in the wall cavity.

As always, offered only as opinion

 

[Shocker]

I am learning that R values aren't nearly as obvious as I thought.

IE: R30 is not that much better than R19, only 4% better in retaining heat. I didn't realize that.

 

[Falcon67]

Going from none to some is a BIG difference. I used R-11 (3 1/2 x 22 1/2" 'glass ) in the walls and ceiling. I also put 1" foam board in the door panels. No wall cover - some OSB, no sheetrock, nothing on the ceiling (just the batts). Bought insulated glass windows for scrath-n-dent prices at the home store. On a real cold (20F is cold here LOL) day I can bring the shop to around 65F in an hour with about 18K BTUs.

 

[walrus]

While more insulation never hurts, some posters on this board often overstate its importance.

I think most people understate it. If it helps keeps dollars in the US instead of sending it to countries who hate us then making our buildings energy effiecient is the right thing to do

 

[redsky49]

I think most people understate it. If it helps keeps dollars in the US instead of sending it to countries who hate us then making our buildings energy effiecient is the right thing to do

While I am not interested in a political discussion of countries that hate us, I don't think that we should characterize people who insulate their buildings to lesser amounts as unpatriotic.

I do want to encourage people to make informed decisions regarding their purchases and assist them in getting the most for their dollar. Rather than continue to hijack this thread, I will post a new thread regarding insulation costs when I have some time.

The results may surprise you.

 

[walrus]

Rather than continue to hijack this thread, I will post a new thread regarding insulation costs when I have some time.

The results may surprise you.

That'd be cool and probably helpfull

 

[mcpt1]

I appreciate all the insights fellas. It's given me a lot to consider. I'm going to go with a higher r value than originally stated R 11 and 19, and just do the lower level where I need it. Appreciate the input