Insulating and Heating Decisions

[dblattack]

Hello guys, I'm needing some opinions on what to do with my shop. I am preparing to drywall so I must decide how I want to insulate.

Garage is 2x4 construction, walls and trusses. I am in Canada where it gets very cold.

1. The best insulation I can get for the walls is R14. Is it worth it to strap the walls with 2x2s to get more insulation?

2. For my ceiling I am undecided if I should drywall the bottoms of the trusses then insulate above, I do want to store stuff in the trusses so this would make it cold space and a bit difficult to access. I think I would end up strapping the trusses as well so I could lay plywood down. Alternatively I could install baffles all the way along my roof sheathing then spray foam over top making the trusses warm space although all my heat would collect there.

3. I want to use a natural gas furnace that I have and I would like to mount it in my trusses but this will create heat issues with its in the cold space. I would have to box it in and insulate it for this to work.

Just looking for some opinions to steer me the right direction. I don't plan to live in this house forever but I do want a nice shop.

Thanks for any advice guys!

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[Beags86]

How's your budget and time frame?
I think I would fir out the walls for a bit more insulation.
And I also would put up a ceiling to keep it from heating the roof trusses area.
Also I quoted spray foam for my trusses thinking the same thing and it was about 2 grand. When a ceiling and traditional insulation is about a grand. So the old fashioned way saves me a grand and I won't spend as much heating it.
Even with some more heat loss of the non sprayed ceiling.
I am not living out there, so the thermostat will spend more time "off" then on.

 

[Outlander]

Watching this one, requirements are remarkably familiar.

 

[p_mori7]

I am in Montreal, so similar weather to Barrie.

Also 2x4 construction.

R13 in the walls, then a vapor barrier, then 1x3 strapping horizontally, then plywood on the walls.

R30 in the ceiling, then vapor barrier, then 1x3 strapping perpendicular to the trusses, then plywood ceiling.

I heat the space with a 5000w shop heater. Keeps 50* on it's lowest setting, 70* on setting #3 (it has up to 7 or 8 on the settings dial).

I have 10' cielings, and use a fan (on 24hrs a day) to move the air around. It helps a lot.

~Phil.

 

[Outlander]

I am in Montreal, so similar weather to Barrie.

Also 2x4 construction.

Just went through your build thread...again

 

[yeldogt]

Obviously -- spray foam would solve all your problems -- even a flash and batt. Have you priced. What's the size. How long are you planning on staying?

Using plastic as a vapor barrier is always a bit dangerous -- having the air space does mitigate some the hazards. Plastic initially makes for a very tight space -- but, it can degrade and any holes can allow moisture to get caught depending on other construction design

 

[86turbodsl]

For a thin wall like that, i'd be all over spray foam. I only have 2.5 inches on my walls in a cold climate and heat with no issues. Spend the big dollars on the ceiling insulation.

 

[DC73]

I stumbled across this article that might be of some value for those of you in Canada: https://www.joneakes.com/jons-fixit-database/793-WHAT-ARE-THE-RECOMMENDED-INSULATION-LEVELS

DC

 

[75gmck25]

Spray foam in the wall is the most effective for 2x4 walls, but it makes it more difficult to add wiring later in the walls. However, metal conduit on the wall can be used for any wiring additions.

It is my understanding that properly applied spray foam can be used directly on the bottom of the roof, with no need for air baffles. In the past, everyone seemed to feel that lack of air circulation next to the roof deck would cause problems, and baffles were needed to allow air to move, but that requirement seems to have changed. I think you can just have the foam sprayed directly on the roof, deck, then close off the soffit vents and your entire attic is now conditioned space.

Bruce

 

[850xpeps]

If you can afford spray foam then it seems that’s what would meet your needs. You could always strap the walls to get r20 batts and poly and then foam the ceiling. Just add plywood up the outside of the wall in between each truss so they can spray across and completely block your soffit and shouldn’t need ventilation if spraying right to roof sheathing.

 

[Dragfluid]

What's the size of the building? (width, length, height) How much time will you be out there, doing what?

Do you REALLY need the space up above for storage? Like I've said in other threads like this, the stuff you put up there will more than likely still be up there on the day that you go to move away. Put racks up along the walls.

My way would be to blow dense pack cellulose in the walls and then 1' sheets of Polyiso. That will give you an additional R6 and also make an excellent thermal break, which helps a lot.

For the attic, I would blow in 19" of cellulose.
Put your hanging furnace under the ceiling, where it belongs.

Take a peek at my build thread for info.

 

[theoldwizard1]

Heat rises. Insulate the ceiling FIRST with as much as possible (12" minimum) and forget using it for storage.

 

[6768rogues]

Most heat loss is through the ceiling so I would insulate the wall with batts that fill the bays and nothing more (assuming a fairly wind proof sidewall). Adding more will be marginal in its effect. I would maximize ceiling insulation and forget about storing stuff up there. Most trusses are not designed for storage and your biggest heat loss will be through your attic access provisions.

 

[justinthurn]

Go to r40 or r50 blow in, in the ceiling before you fir out the walls. Foam in a can around the outside of electrical boxes and use Vapor barrier taping the seams. Heat loss in the ceiling and air infiltration is way more critical than going from r14 to r19 or 21 in the walls. I would skip the attic storage and spray foam is way expensive compared to the above.

 

[mnwebb]

75gmck25 idea about foaming under the roof didn't work in my home, but it was open cell and 12 years ago. Still had heat loss that made for some nasty ice damns. Our roof needed to be re-done so I had them add a panel that had insulation and an air vent and now no issues.