Heating 23x23 - insulation question

[derek_gardner]

Attached is a photo of my 23x23 garage .. no insulation or dry wall yet. I plan on getting a heater in the upper corner of the garage and running a gas line in.

I live in Southern Ontario and its cold in the winter time.


First question is about insulating the ceiling. My original plan was to drywall it then blow in the insulation. But then I got thinking, can I do the spray foam insulation against the existing ceiling and keep my rafters? If I do that, do you think it would be much more cost to heat it with such high ceilings?

Next question, If i drywall the ceiling and blow in the insulation up top, I was hoping to lay some ply wood down for some storage in the attic. The joists are 2x4s. So, for that section am I better off to lay in the insulation bats and blow in the rest? Im just concerned with blow in that it won't be thick enough if I put ply wood down on top of it.

 

[James-W]

Spray foam has a higher R-value per inch, but it is more expensive too.

 

[Voi]

Hip roofs are not as straightforward to ventilate.

Does the building have overhangs? On all four sides? Are the soffits ventilated?

And roof vents at all?

If the roof is going to be a lot of work to ventilate then closed cell spray foam on the underside of the roof sheathing will be the quickest way to insulate. But it will be expensive and won't do anything to reduce thermal bridging through your trusses. And if the upper chords are 2x4 you don't have a lot of room to put in much insulation. On top of that you may need to cover the foam with drywall for fire rating.

A ceiling with a thick layer of blown in will probably be your cheapest way to good insulation but a ventilated attic space is necessary and you won't have your storage.

Another option is rigid foam above your roof deck but this is labor intensive and only feasible if you're roof is in need of replacement. But it cuts out the need for the interior ceiling drywall and does a much better job of reducing thermal bridging.

 

[90zcar]

Don't do drywall. Do a metal roof ceiling. Much cheaper, easier and quicker. Looks nice in the end aswell and lasts longer.


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[rebelranger]

90zcar, where are you finding metal cheaper then drywall? Is at the cheapest 1.39 a sqft vs about .3 a sqft for drywall.

 

[90zcar]

I just bought some. I got 10 sheets that are 23 foot long, all the j channel and hardware for $500


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[90zcar]

The way I figured it out it was cheaper once you figured in finishing material costs and paint for the drywall. Plus the time you save .....



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[CNGsaves]

Don't do drywall. Do a metal roof ceiling. Much cheaper, easier and quicker. Looks nice in the end aswell and lasts longer.

^ ^ ^ This.

Since in Canada, be sure to put in vapor barrier that has every opening taped up AFTER you get all your electrical, lighting and insulation done.

When finishing rough in, remember all your important items for ceiling . . . . hanging electrical reel, airline port for hanging air reel, black pipe steel NG line, outlet for hanging heater, etc.

 

[Dragfluid]

Steel panel ceiling, 19" of blown in cellulose, that will settle down to around 17". Forget about using the attic as "storage". Your trusses aren't rated for putting a bunch of **** up there that once it's up there, you'll never go near it again in 10 years. You're in Ontario. It gets cold there, as you know. You need insulation!