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garage insulation


aniceguy

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Maybe someone can help with an insuation question

 

The goal is to basically have a garage that will remain above freezing +1 or +2 as a minumum. The side walls are not backing onto a house and have drywall with no insulation between the studs open soffits and brick exterior. The garage is a 2 inch insulated door and the back wall is attached to the house. the celing joice are open and exposed with sheathing I can put some pics if need be

 

I was thinking of putting batt insulation and a vapour barrier between the roof rafters touching the roof decking, and using a blow in cellulose into the walls by cutting a hole and injecting it with the cellulose.

My question is, has any one done this and do you think I ll be able to keep the garage above freezing. With the extreme cold we had the coldest it got was -11 at he front entrance of the garage.

thanks

 

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I'm sure the colony of mice that will move in should certainly give off enough body head to keep the place above freezing! :tease:

 

I wish I could help.

 

My garage is insulted. Never gets bellow freezing, but it's attached to my house. And it's full of mice.

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To many variables without seeing the floor plan.... As your description leaves a lot to the mind to try and compute... Feel free to pm me a few pics... I am especially concerned about your mention of the open ceiling and your suggestion of putting insulation and VB in between the roof trusses. I assume you are meaning in keeping the ceiling open and placing batt insulation and VB from soffit to peak? BAD idea unless you add an conduit of airflow between the soffit and peak... You are begging for mould in between the sheathing and insulation if this is the case....

 

Best case is to insulate and VB to ceiling joists and drywall the ceiling, after VB and drywall use either batts or make an Access hatch and have it blown in.... For the walls Use a hole saw to cut 2" "plugs" in the walls and fill with blown in...

 

Hopefully this helps.

 

G.

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also an idea is spray foam in the walls, though it may be (most likely) more expensive than a regular batt insulation, it's a better product and I've heard (don't quote me lol) that mice and other rodents don't like it so gnawing through your walls for a place to breed is less of an issue.

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The only way your going to insulate the walls properly Louis.. is to rip the drywall off. If it was framed well it has firestops in the walls mid way.

 

That said... My 24 x 24 x 10 high has two walls shared with the house.. and it also has living quarters over it. All insulated.. Garaga doors... and it keeps beer rocky mountain cold but they don't freeze. I highly doubt with only one wall shared (unless you take all the insulation out of that one) that you'll keep the garage above zero in anything below -10C.

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Even with a well insulated garage, you only keep cold out if there is heat within. Where walls are shared with residence, there is heat transfer and added shelter from external cold. A free standing structure needs some heat source to stay above freezing, especially in this more severe winter. I had one small electric radiant heater with fan, and it kept our fully insulated 2 1/2 car garage hovering at zero during cold snaps.

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I work with a major Insulation company on a weekly basis (home renovator) doing this very job. Its fairly strait forward You have to gut all drywall on ceiling and the walls ..Install Moore vent on the roof decking between the trusses (if you have vaulted ceilings) . Install insulation and vapor barrier OR spray foam directly over the more vent.No vapor barrier is required with foam. If you have a false ceiling with lots of head room you can instal vapor barrier in the attic and blow in cellulose on top.With cellulose soffit venting is extremely important, again condensation and air flow..
on exterior walls the ONLY way to do it is give Insta Insulation a call and spray foam.. Drill and fill cellulose in a garage is bad news and is begging for mold. There is no vapor barrier in a garage wall almost 90% of the time. In the summer fall and spring condensation will get trapped and destroy your garage over time. If the building is completely free standing this can get expensive as all exterior walls need foam. I hope this bit helps and of you want to pick my brain some more, pm me and ill gladly give ya my cell phone # to discuss further
As far as keeping it above freezing don't count on it without a heat source, no matter what you do..
Regards,Ron

Edited by tb4me
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I've got a free standing 440 sqft garage on slab. The walls are 2x4 insulated with batts, vapour barrier and 3/8 spruce sheeting inside. The roof trusses have vapour barrier and 6+ inches of batts up there. Between each truss on the soffits there is a moore vent. The garage door is about 1 3/4 foam insulation. No windows, only a man door. I have a Cozy brand gas, direct vent wall heater, costs me about $100 per winter(dec to april) and I have the thermostat set at +7.

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I work with a major Insulation company on a weekly basis (home renovator) doing this very job. Its fairly strait forward You have to gut all drywall on ceiling and the walls ..Install Moore vent on the roof decking between the trusses (if you have vaulted ceilings) . Install insulation and vapor barrier OR spray foam directly over the more vent.No vapor barrier is required with foam. If you have a false ceiling with lots of head room you can instal vapor barrier in the attic and blow in cellulose on top.With cellulose soffit venting is extremely important, again condensation and air flow..

on exterior walls the ONLY way to do it is give Insta Insulation a call and spray foam.. Drill and fill cellulose in a garage is bad news and is begging for mold. There is no vapor barrier in a garage wall almost 90% of the time. In the summer fall and spring condensation will get trapped and destroy your garage over time. If the building is completely free standing this can get expensive as all exterior walls need foam. I hope this bit helps and of you want to pick my brain some more, pm me and ill gladly give ya my cell phone # to discuss further

As far as keeping it above freezing don't count on it without a heat source, no matter what you do..

Regards,Ron

^^ Bingo!

 

S.

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How long have you had the house?

Do you plan on living here for awhile?

What are you using the garage for? storage / keeping vehicles. both

What heartache is the freezing causing?

You will need a heat source in the winter if you insulate. Or you could be making a fridge.

Whats your budget?

Do you think this type of winter will be our typical?

 

If you can answer these questions, I can try and help

 

MM

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thanks for the replies, as soon as I get outside today I ll post up pictures

I built an addition effectively bumping the garage out 5 feet to accomadate my boat todaya dn any larger one in the future. I currently keep it at my shop in the back but would like it home. I dont want it in a freezing environment, hence the insulation question.

It seems that blowing in cellulose without a vapour barrier is a major issue as is the batt in the ceiling. I ll put up pic and see what you think

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Nice, This will be a help to see your situation and point you in the right direction. I asked some of the other questions because this winter there is a bunch of garages that are freezing up for the first time. This weather is unusual for southern Ontario. My father claimed for the first time in 20 years..the water bottles in his garage froze. For the record I am licensed carpenter in a 5th generation construction business, I have been on the tools for the last 22 years. I can give you advice and you can take it if you like. Oh also, I'm Scotish and treat your money like it was mine.

cheers MM

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Make sure the vapor barrier is between your ceiling and the insulation. So you can't put insulation batts bewteen the joists and VP on top of that cause that would cause dampness in your insulation.

 

My fully insulated garage is always 15 deg warmer in the Winter and 15 deg cooler in the Summer. It has to be at least -20deg outside( a couple of days) for my minnow water to freeze, with a aerator pump going in it.

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hi there

here is the view facing the house, there is a storage loft about8 feet out that id like to put doors on to enclose it. the ceiling is above it

 

67FA862A-B997-4D1F-9577-34023C09F00E_zps

 

here is the front view again with a loft built into it

7D5740A8-9D6B-4433-924D-D6BB07410E12_zps

 

One side of the garage

 

4D377D6D-0C3E-41C2-AFB0-01B79FE3419B_zps

 

and the other side

 

FD02ABB6-AD4C-4048-B219-F72B2393198C_zps

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ok, let's start with....Your loft is, is not a loft. From the looks of it those are a standard truss, designed to carry

 

the load of ceiling and that's about it.

 

Loading too much on the bottom cord is a bad idea. Stuffing Batt insulation between the rafters is not a great

 

approach to insulating the roof or ceiling.

 

A required air space of a 1.5" is needed between any insulation and roof decking in any roof application. This

 

allows for the roofing material (shingles usually) to breathe a bit. If it is a steel roof, or shingles almost worn

 

out, let me know, and there are cheap ways to gain the required air space.

 

The "stuff" in the loft....Can it be removed and go somewhere else? Or do you really want an unpractical,

 

area to put things. I ask because putting in aflat ceiling attached to the truss bottom cord, putting in some

 

ceiling joists in your addition area, and blowing in some cellulose in the new attic area

 

would be fairly simple and provide an excellent and cost effective attic. Cellulose is cheap and does a very

 

good job, much better than any batt. If you ever insist on batt insulation IMO buy roxul, fibreglass batts are not

 

very effective.

 

Once you have an attic insulated you have achieved a 80% gain in your heat loss. (Drywall, vapour barrier, r40-50 cellulose.)

 

Your walls.... what is your exterior cladding? I will assume it is siding, regardless.....I highly doubt you want to tear off all the drywall...IMO and proven,

 

Vapour barrier is not going to make any difference in your wall cavity. It is known that 2 coats of latex paint

 

are the equivalent to a 6 mil vapour barrier.

 

VB is a canadian thing, which is currently under debate. This is with a drywall tight approach.(which is

 

accepted in the U.S.) When people talk of rotted walls, vapour barrier has no effect in causing or preventing

 

this. VB can contain mould issues but does not eliminate them. An Air leak is a air leak,

 

The chances of a perfect VB are slim to none IMO. I do use VB and try to do the best job possible, but in a

 

retrofit like yours it would not be of major concern IMO. Mould is a whole story in it self and is a serious

 

concern, but can discussed in detail later if you want. I would continue with your plan of

 

blowing cellulose in the walls either from the inside or outside. Fireblocks are not much of an issue and easily

 

detected by a experienced insulator.

 

Again this is all due to cost effectiveness because of a retrofit. In A new building MY approach would involve

 

vapour barrier and possibly spray

 

foam. Insulating under your concrete floor. Lots of awesome ways. Do not forget that you can put all the

 

insulation you want in the walls and ceiling,but you will still have a 16 x 8 garage door that is a large source of

 

cold and draft.

 

Truthfully I would keep all the money in my pocket, and do nothing. Freezing up maybe 6 days a year

 

wouldn't/doesn't bother me too much. Build a dandy new shop in the future. :angel: I know the views expressed

 

are solely mine. Construction allows for ALOT of different opinions. Listen to them all, and do what makes

 

sense to you and your wallet.

 

MM

Edited by mcdougy
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