Garage insulation and heating please give me some advice

Freestyle72

Freestyle72

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Ok so I am really interested in insulating my 1 car garage because since the garage is small the material costs should not be too high. My garage is my bike shop. And lately it’s been cold as hell in there and is causing me to be lazy to go out and work on the bike. To combat this I intend on insulating it and then doing either a 240V construction heater or an in wall propane/natural gas heater. So my dilemma is that my garage is already small. It’s a 1 car garage. The inside dimensions are 12.5ftX19.5ft. It has cinderblock walls with a red brick veneer on the outside. I don’t want to lose anymore space on the inside so my plan is to insulate the outside and put up siding over the insulated wall. The roof however I want to insulate from the inside as there is lots of space up top. Is there any reason why insulating the outside of the cinderblock wall would not be as effective as insulating the inside? The only thing I need to work around is a meter box and that’s it the rest is a piece of cake.

So my main question is there any reason I should not insulate the garage from the outside? And which would be the better bang for the buck a 240V electric heater or a “mr heater” style in wall propane or natural gas heater? Bearing in mind the in wall deal will run me close to $700. And the construction heater will run me $0-$50. I guess to re-formulate that question would an electric heater do a good enough job to heat up that small garage space assuming I did R20-R30 on the walls and roof without costing an arm and leg in electricity?

Thanks for your thoughts guys and I am looking forward to hearing your experiences
 
I am not a construction expert but I recently built an insulated 7.5 x 13 shed (I don't have a garage) for the sole purpose of housing/working on my bike, so I hear where your coming from. If the outside is brick, and you want to insulate the outside, how do you plan to fasten the siding to the brick? Your going to have a tough time doing this, not to mention the questionable effectiveness/looks. I can understand your want to have more space. Consider 2x2 framing on the inside with 6 mil polyethelyne vapour barrier (the regular stuff) and R-8 or R-12 (maybe, depending on space) insulation. You cannot cram in insulation, it needs to be uncompressed to work effectively. DoubleJ's spray foam solution is a good idea too, but a good bit more expensive for a small job like this, but I would seriously look at it if space is the major issue. Your not going to have room for R-20 insulation using 2x2. Remember you always want your vapour barrier on warm side (inside most) part of the wall. Is it going to be heated 24x7, or only when you work on it?

I only heat mine when I work on it, just bought a $20 15-amp space heater, in about 20 minutes you need to shut it off, or its a sauna. Your heating depends on your insulation choice. If its only when you work on the bike, go electric, but if its frequently on, spend the money and go nat gas.
 
You can definately throw up some rigid insulation and then some siding. A lot of businesses do this with EIFS (Exterior Insulation Finish System). They buy a brick building then refinish it to their style. EIFS is a stucco on rigid insulation system. I like Dryvit cus of the puck system which easily allows water to drain when it gets caught behind the insulation system. Which if you do coat the building in insulation and a finish of some sort please watch and keep the weep holes in the brick clear. You will see them along the bottom of the wall, top of windows and doors etc. Theres an airspace behind the brick (not on century homes btw) that is ment for water to stop flow to the bottom and out. Block this and your brick will soak up the water and salt and will eat the brick away.
 
I work for an architecture firm btw. Worked on Maple Leaf Gardens.
 
If you want to do this with minimal space lost, 1/2" drywall on z-bar with 2" Rigid insulation on the inside works (gives about R-10). I am not sure if you could do z-bar and foam on the outside (physically it's possible, not sure what code allows). You must use drywall over the foam to keep the foam from burning.

Keep in mind that depending on your house design, you may not be able to insulate on the outside as you will come too close to the property line (there is a mandatory setback distance from the line, most builders build to that line when the house is first constructed).

If you are insulating the outside of the walls, I would think about going with the gas heater and leaving it on, if you are insulating the inside, electric should be fine. If you are insulating the outside and letting the garage freeze, you will have thousands of pounds of masonry at freezing temperature when you go into your garage and turn on the heater. Kat, do you have any experience with masonry through repeated rapid 30 degree temperature swings? I don't so I have no idea whether it would be a problem or not.

Personally, I'd go with the foam on the inside. You avoid potential zoning/building code issues and if you (or a future owner) decide they don't like the siding, if you have anchors drilled all over the brick, you can't easily go back. No one cares about a few holes in the garage walls if they decide 5" of space is more important than insulation.
 
Its a 97 sq. ft shed. doubt he needs to worry about setbacks , building codes or what ever. Thats for the second one. the first is a problem by the size. Do it inside and don't let the inspectors near your place. Nothing but grief.
 
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GreyGhost said:
If you want to do this with minimal space lost, 1/2" drywall on z-bar with 2" Rigid insulation on the inside works (gives about R-10). I am not sure if you could do z-bar and foam on the outside (physically it's possible, not sure what code allows). You must use drywall over the foam to keep the foam from burning.

Keep in mind that depending on your house design, you may not be able to insulate on the outside as you will come too close to the property line (there is a mandatory setback distance from the line, most builders build to that line when the house is first constructed).

If you are insulating the outside of the walls, I would think about going with the gas heater and leaving it on, if you are insulating the inside, electric should be fine. If you are insulating the outside and letting the garage freeze, you will have thousands of pounds of masonry at freezing temperature when you go into your garage and turn on the heater. Kat, do you have any experience with masonry through repeated rapid 30 degree temperature swings? I don't so I have no idea whether it would be a problem or not.

Personally, I'd go with the foam on the inside. You avoid potential zoning/building code issues and if you (or a future owner) decide they don't like the siding, if you have anchors drilled all over the brick, you can't easily go back. No one cares about a few holes in the garage walls if they decide 5" of space is more important than insulation.
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Code requires that you have a min R12 in walls. Obviously a garage is different and isnt typically insulated. That being said an R10 insulation in combination with the rest of the wall will prob bump up to an R12. Zoning yes is a consideration though there is a minor varience process you can do. Look at your site plan and the local zoning (you can usually find zoning information online). Depends where you are, the new trend is to build the max allowed on your site but not always. Its more the newer behaviour with the mass developements.

Masonry can definately handle the temperatures. In a larger building we put in expansion joints to handle the expansion and contraction that occurs but in a garage setting it will be fine. As long as the weeper holes are allowed to drain. Look at brick buildings if you see what looks like a salt stain in the brick that is due to water being trapped. And it is salt you are seeing. It will destroy the brick.

The holes in the masonry is yes a very valid concern. You can specify that a contractor punches holes through the mortar joints only and they you only have to patch those later on if need be.

IF you put insulation and drywall on the inside please do not forget to vapour barrier it between the insulation and drywall. That will help keep the moisture build up out of the garage. And yes there will be moisture build up due to the transition of temps inside vs outside.
 
DoubleJ said:
Its a 97 sq. ft shed. doubt he needs to worry about setbacks , building codes or what ever. Thats for the second one. the first is a problem by the size. Do it inside and don't let the inspectors near your place. Nothing but grief.
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Certain size buildings do not require inpections. A shed should be fine but your local zoning will say. If they care.
 
GreyGhost said:
If you want to do this with minimal space lost, 1/2" drywall on z-bar with 2" Rigid insulation on the inside works (gives about R-10). I am not sure if you could do z-bar and foam on the outside (physically it's possible, not sure what code allows). You must use drywall over the foam to keep the foam from burning.
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This is what I was thinking too. Insulating the outside means you have to heat the brick and cinder block structure as well. The concrete floor will act as a heat sink pulling heat out of the walls (as you're trying to heat them) as well.

Even with 2" Rigid, z-bar and drywall you're only losing 5" of inside width.
 
All you really need to do is insulate and seal the roof and it will heat with a 1500 watt space heater, cost will around 30 cents per hour to run the heater, this will be by far your cheapest option. My attached, sealed but uninsulated single car garage heats with a 1500w heater temp rise is around 2 deg per hr.

My 5000 sq foot shop has uninsulated block walls and 20' ceilings, the important thing is getting the ceiling insulated and stop the air from going out there.
 
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caboose483 said:
This is what I was thinking too. Insulating the outside means you have to heat the brick and cinder block structure as well. The concrete floor will act as a heat sink pulling heat out of the walls (as you're trying to heat them) as well.

Even with 2" Rigid, z-bar and drywall you're only losing 5" of inside width.
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Floor is not a heat sink.... Concrete is until it reaches a matching temperature. All masonry. But once it absorbs heat it is an awesome conductor. They put only insulation under the floor in high temperature varying areas to protect from ground moisture. Your thermal bridge is at the exterior wall and floor joining condition where there is no insulation.


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Thanks for the great feedback so far guys has really given me a lot to think about. Another tricky one is that my electrical panel is almost flush to the wall so insulating will either force me to cover part of the panel which will prevent me from removing the face plate to add any further breakers, and I may be denied access to running more wires out the side as well…. I guess I could build an enclosure around it and insulate that as well… It can be shifted over about 8inches but I may have to re-wire quite a bit, and get the power disconnected by Milton Hydro which is also a pain and there’s the worry of the main feed lines not being long enough for the new orientation… So an enclosure might be the best thing however ugly…

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Would R12 walls provide pretty decent insulation if I could do the ceiling in let's say R30? I don't want it to take forever to heat up or have exorbant heating costs... original reason why I wanted R20-R30 walls and ceiling was so that it would be noticeably warmer... if R12 is not going to make a big difference I'll probably just say screw it and put up with the cold.
 
Freestyle72 said:
Would R12 walls provide pretty decent insulation if I could do the ceiling in let's say R30? I don't want it to take forever to heat up or have exorbant heating costs... original reason why I wanted R20-R30 walls and ceiling was so that it would be noticeably warmer... if R12 is not going to make a big difference I'll probably just say screw it and put up with the cold.
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How warm does it need to be while you're in there?

I have found that 8-10 degrees is plenty warm enough for wrenching. I was doing this for one winter in an insulated garage and all I had for heat was a mid size electric floor heater. I'd turn it on high then go back inside and have breakfast and coffee. 30-45 mins later it was warm in there, turned the heater on to low and that was plenty.
 
is it attached to your house? or is it a detached garage?
 
Do not forget to insulate the garage door. I used styrofoam sheet insulation on the door and under drywall on the walls. I also installed interlocking rubber tiles on my floor to mitigate the cold. It makes it much more comfortable if you're sitting down or on your knees working on your bike. My toy garage is about 12 x 20 x 9 and I installed a standard 6' baseboard-type heater. I have no problem maintaining 20C or higher whenever I want to work in there. I also maintain a minimum temperature of 10C in the winter - frozen tools are not enjoyable to use. Next year - air conditioning!

Good luck with your project.
 
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^^ This

i was in the same boat....i had open ceiling and the entire roof was open to the outside by the wall for circulation...so any heat generated would rise and escape through the openings. $13 later i bought thin plastic sheeting and ran it across the entire ceiling. This stopped heat escape and also effectively lowered my ceiling. Next step is garage door insulation but i can already feel a difference. I dont use heaters but two 500W halogen work lights for lighting and heat.

I can thank someone on GTAM for that idea last winter.
 
R12 was a standard wall rating for yrs, the code changed Jan 2012.
However R12 will be a very noticable difference , your in a monoblock constructed garage and it will radiate cold from that block wall. Putting insulation onthe inside is your maximum gain. I've done a bit of this, best bang for buck is rigid foam SM type onto the block with adhesive and a few masonary nails to hold it till the glue sticks, then drywall directly over it. Use tapcon fastners to mount drywall thru foam into the block. You get protection from sparks and grinding stuff for the foam. 1" foam,1/2 drywall, your not loosing much space.
You dont need a vapour barrier here, its not living area so no showers/cooking ect producing moisture and foam board insul is not affected by moisture changing its insulating properties.
The concrete floor IS a heat sink, the largest hardest part of a garage to fix is the floor runs outside under the door and concrete conducts cold into the room. A large rubber mat makes this a happy place.
Remember if you insulate the ceiling you need to maintain roof venting, generally a garage roof gets no vents, the heat in summer can just push down into the room, you dont want to cook your shingles.
Is the door a roll up or folder? You can insulate the folder and it will still swing not bad. If its a roll up it will need to be re-tensioned after adding the weight. Unless your been shown how to do this you can loose a finger be careful.

If you go electric heat it's plug and play and safe, add a pool heater timer and warm it when you want. If you go natural gas you need venting and a gas line run and inspections ( you can do the work but your ins carrier will want to know its inspected), be careful with propane , burning LP produces a bizarre amount of moisture and when you start it in a small space condensation forms on every metal surface.
 
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Cat13 said:
I work for an architecture firm btw. Worked on Maple Leaf Gardens.
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There is so much good info happening in this thread.Awesome peeps! When i did my garage reno back in 06,my thread got pummelled to death by gldwngr and Lazer.There was a bunch of trashy fun going on that Cat13 would find interesting to read.
Btw,i use a 240v construction heater in my 22x18 cave.With the insulated door and pink in the walls it's great.
http://www.gtamotorcycle.com/vbforum/showthread.php?23353-Garage-reno&highlight=garage+reno
 
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