2x4 vs 2x6 walls

[253rider]

Just getting ready to order my garage package and have to make a choice on walls. I'm going to heat the garage but only when i plan to use it so it won't be heated all the time. Can i get away with 2x4 or would i have to go 2x6 for more insulation. The winters here get down to -30c or so for a couple of months.

 

[MScott]

I had the same decision to make, although I am going to heat the garage. I am going with 2x6 on 24" centres. Cost difference is negligible, insulation cost also not much more, but much more efficient. You don't intend to heat it now, but you might change your mind later and it is much easier to be prepared up front.
Also, keep in mind that your garage will be much cooler in the summer with the extra insulation. You don't say where you are (your location should be in your CP info so you get better and more relevant responses esp. to questions about building) so cooling may or may not be a factor.

 

[Grabber70Mach]

Nothing to add but agree with the above analysis.

 

[Gary S]

A 2x6 wall is more for structural strength and to fit additional insulation. A 2x4 wall can be built to R20 using R13 blankets and a high R value sheathing on the outside. You don't need more than R20 in a wall if you put in a R50 ceiling with it. At that point, almost all your heat loss will be in your R3 windows and R6 doors. Even the high R rated garage doors will never achieve the rated value because they don't seal that tight in the frame. Loss will be around the door, not through it.

 

[Responder]

Just remember that you will probably be hanging stuff or attaching shelves to the walls. 2x6 got my vote when I did mine.

 

[DCarr]

2x6x10's here on top of 3' of block. R19 in the walls and the foil wrap around the exterior of the building. Huge difference in my shop that it is outside w/o any heating / cooling.

edit: I also went on 16" centers

 

[MacTexas]

Different problem in Texas, trying to keep the garage cool. I went with 2X6 and I can tell the difference with the extra insulation.

 

[38Chevy454]

I also went with 2x6, although I also have 12 ft height. R-19 insulation in walls, R-38 ceiling. I made extra effort to seal it tight with wrap and also all air intrusion points. I don't heat mine except when working out there, and even after a week of single digit (fahrenheit) lows and near freezing max, it stays above freezing inside the garage. Might be mid-40's, but that is still a big difference. Summer it stays much cooler as well. I have a lot of shelves hung off my walls and the 2x6 is just that much better for that also.

 

[GYPSY400]

I'd go 2x6.. For strenth and insulation mostly
I don't even think I have the option to go 2x4 around here ( northern Ontario)

 

[kbs2244]

I am swimming upstream on this one.
I just do not buy into the idea that 2x6 on 24" is stronger than 2x4 on 16".
And in a rarely heated shop the extra insulation of 2x6 vs 2x4 isn't going to mean much.
I would go with 2x5 on 16" centers.
Much more common when you go to hang stuff inside.

 

[koditten]

I did 2 x 6 for noise reduction. I work odd hours, I didn't want to wake up the wife making a bunch of noise in the shop.

 

[Kevin C]

2 x 6's are nice on tall walls because they tend to dry a bit straighter. As far as strength goes, I dont think its much of a factor. The wall strength should be in sheer, and that's controlled by the strength of the joint where the plywood is nailed to the face of the 2 x 4.

In the other direction, you will get a stiffer walls with the 2 x 6's , but then again, its not like the 2 x 4's are an issue. I did add an extra 2x4 around the door frame.

As others pointed out, the main reason is to allow wider spacing the the studs. That allows wider insulation with less thermal bridging and of course thicker insulation.

If you go 24" on center you have less studs to use for supports ( shelves cabinets etc). You also have wider spans on your sheet rock.

Those are not big issues.... For simplicity in insulating the 6" studs work the best. One interesting thing, is with the 10' walls in my shop, the heat loss from the walls was pretty significant.

I went 2X4's with 2" of foam on the inside. It seems to work really well but its a bit more work.

Bottom line? Either will work, and 2x6's seem to be a good choice. For really cold conditions a layer of foam sheeting without thermal breaks is worth considering.

 

[kevin47]

I'm thinking of also going with a "Big *** Fan" for the ceiling in the summer...Or winter...But I'd guess you have to turn it down to prevent mig & tig shielding gas problems...

Is foam going to be cheaper that the fiberglass...?

 

[hockey88fan]

How bout 2x6 on 16" centers? Not even sure you can go on 24" centers around here.

 

[mebuildit]

Go with the 2x6's and after all of your electrical is done, use that spray in foam for insulation. It will block any nooks and crannies and keep a nice insulation barrier. I live in Arizona, and I'm getting ready here to build my 2500sqft shop. I will be doing that, only because it's friggin hot here.
You will be amazed at how much better having a 2x6 insulated shop is. Temperature and quiet from the outside world.

 

[Steevo]

My shop is in eastern Idaho, and I built it using 2x6x10' walls (16" centers) on top of the 18" foundation wall. I used R21 bat insulation in the walls, 5/8" sheet rock everywhere, and had 18" of insulation blown in the attic, for an R60-ish ceiling rating.
Insulated doors, too.
It is heated to 50 degrees all winter, and higher when working.
I am so glad I spent the money on the walls, insulation, etc., because it costs less than $30/month to heat using a natural gas hanging unit heater.

 

[pudgybear]

check with your building inspector in some areas 2x6 is now the code

 

[wssix99]

How about going 2X6 and using R13 insulation in the walls? (Like a 2X4 wall)

If you ever want to upgrade, all you have to do is add more insulation.

 

[scrape53]

"How about going 2X6 and using R13 insulation in the walls? (Like a 2X4 wall)

If you ever want to upgrade, all you have to do is add more insulation"

fiberglass has to touch on all six sides to work properly... otherwise you just have a filter

 

[Highbeam]

fiberglass has to touch on all six sides to work properly... otherwise you just have a filter

Myth. Tell that to the attic insulation. Lots of insulation out there that doesn't fill the cavity. Heck, my home was built with 1.5" thick R-5 faced batts in 2x4 walls. The R-value is not dependent on encapsulation.

 

[NUTTSGT]

If I built another garage, it would have 2x6 walls for more insulation.

Whether you're heating/cooling all the time or not, the more insulation will help maintain the current indoor temperature preventing temp swings which can cause things to rust more easier.

If you decide to start heating/cooling all the time, it's money well spent.

 

[ClickClickBoom]

Myth. Tell that to the attic insulation. Lots of insulation out there that doesn't fill the cavity. Heck, my home was built with 1.5" thick R-5 faced batts in 2x4 walls. The R-value is not dependent on encapsulation.

Your insulation wasn't installed correctly, period.

Fiberglass insulation relies on the air pockets created within the mat to provide the R value. If there are spaces where the mat doesn't meet the studs/ rafters then those areas aren't being insulate. If the insulation is compressed, then you are not getting the stated R values.

If there are uninsulated areas within that wall/ ceiling assembly it lowers the R value of the entire assembly significantly, not just the small portion where it's not insulated correctly.

for more info on the subject check out:
http://greenbuildingadvisor.com/

 

[rburke65]

I also went with 2x6" walls, 16" on center because of the full attic and an 8x12 roof.

 

[scrape53]

"Myth. Tell that to the attic insulation. Lots of insulation out there that doesn't fill the cavity. Heck, my home was built with 1.5" thick R-5 faced batts in 2x4 walls. The R-value is not dependent on encapsulation."
building science actually and fiberglass batts are apples to oranges compared to blown in attic...there is also a reason that the 1.5" is no longer used...just because something has been done doesnt make it right

 

[jumpingryan]

To the person who suggested to add some insulation now, and more later..... I would be cautious about not finishing a working garage and leaving exposed insulation and/or vapour barrier across the whole garage.

Fibreglass is flammable, spray foam (without a fire resistance coating) is flammable, vapour barrier is flammable.

While garages are not necessarily held to the same standard as houses, fires can be a real drag on your property and others.

A torch, or a spark on sawdust on the floor can more easily spread to walls and then the whole garage with flammable walls.

R

 

[Colonial Cobra]

My detached garage is 2x6 on 16" centers. My neighbor did 2x4's staggered on 2x6 sill.

 

[dbonne]

I went with 2 x 6 on 16's. The price difference (for the lumber and insulation) will soon be paid back in heating and air conditioning savings.

 

[volaredon]

I am swimming upstream on this one.
I just do not buy into the idea that 2x6 on 24" is stronger than 2x4 on 16".
And in a rarely heated shop the extra insulation of 2x6 vs 2x4 isn't going to mean much.
I would go with 2x5 on 16" centers.
Much more common when you go to hang stuff inside.

2X5? where do you buy those? I know a "2 X 4" is not actually 2" X 4"

IDK that 2X6 on 24" centers is stronger than 2X4s on 16"s would be; BUT I do know w/o a doubt that 2X6s on 16s is stronger than 2X4s on 16s. and MUCH stronger than typical garage construction of 2X4s on 24s as many commercial "garage builders" like to use.

I built mine 2X4 on 16s and all stick built; If I were to do it again or different it would have been 2X6s on 16s, and everything else just as I did it.
I am looking at the strength factor as I have my attic STUFFED with car parts, camping gear and more.

 

[Nowater]

Pay close attention to air sealing as that will be very important in any heating or cooling area. One thing you can do is run a small continuous bead of adhesive each side of the 2 by member along the plywood wall to block air infiltration. It also makes the wall much more stiff. As stated, around the garage door will be a problem, and I have not yet seen a real elegant way to air seal these doors. Can anyone chime in?

 

[cbracer]

If you want to seal sound from going through a wall there isn't anything better than staggered 2x4's on a 2x6 sill. Amazing sound isolation

My detached garage is 2x6 on 16" centers. My neighbor did 2x4's staggered on 2x6 sill.