2x4 or 2x6 Ext Walls?

[duneslider]

Most studies that I have found comparing the cost of moving to 2x6 vs 2x4 relating to energy savings put the pay back of this upgrade at around 50 years. This could vary depending on location but I think the studies I have seen were in the michigan area which is a pretty cold climate zone and would benefit more from the insulation than some locations. Payback also depends on energy costs. I live in a relatively inexpensive energy cost area. Someone that has to buy heating oil is going to see a faster payback due to high heating costs.

 

[billconner]

Now I'm not sure if a NY amendment or if it's in the basic IRC, but the continuous insulation is required in NYS, and clearly of high value. Everyone use the XipR panels.

I like the 2x6 for economy and aligning rafters (or trusses) to eliminate the double top plate and ease of as double stud corners. Seems to make wiring and plumbing easier as well, but YMMV. Probably rarely pays back for just the insulation.

 

[nmk_61802]

Are you having an inspection done? Looks like Humble adopted the 2018 international energy conservation code. For your zone and wood walls you may be required to have either R13 walls plus R3.8 foam board or R20 walls (which would need 2x6).

 

[Metal-Marc]

I have learned many things over the years, among them the value of "doing it right"; and more insulation is better. When in doubt, "Build for Stout". If 2X6 framing is within your budget, it will eventually pay off in savings, but it may take a long time.

You get a diminishing return the higher R value you go. If you get a ROI of 10+ years, you're not saving anything.

If I were to build a shop from scratch, I'd go 2X6. That being said I'm currently insulating my shop, which was built on 2X4, and I'm going for R14. Since I'm keeping the temp at around 55-60, there's no need to spend more on insulation just to save a hundred buck a year. YMMV

 

[CraigStu]

Now I'm not sure if a NY amendment or if it's in the basic IRC, but the continuous insulation is required in NYS, and clearly of high value. Everyone use the XipR panels.

I like the 2x6 for economy and aligning rafters (or trusses) to eliminate the double top plate and ease of as double stud corners. Seems to make wiring and plumbing easier as well, but YMMV. Probably rarely pays back for just the insulation.

I knew I had seen something about 2x6s being used in such a way as to reduce X so that almost covered the extra expense of the 2x6 but couldn't remember the details. Thank you for reminding me.

 

[Yankee2bbq]

The walls on my shop are 2x6. I am going with 3inches of foam insulation. I live in northern Arkansas.

 

[Karl1163]

I built a 600 SF addition to my house and also a 12x12 "art workshop" shed with 2x6 studs and R21 batting insulation. I did so on the house because I couldn't get the R value required by code with 2x4 studs and the old-style stronger construction I wanted (solid sheathing, fiber cement siding). I did calculate the ROI, but the part of the house is noticeably quieter and easier to control the temp. the shed is heated with a radiant space heater all winter (it doesn't run all day) and window A/C in the summers. The main problem is you'd have to order frame extensions for the windows to fit deeper walls or do like i did and add them yourself. for the shed I just used standard windows and coffered their frames into the walls, which was more hammering but less finicky to fit.

 

[Falcon67]

Guys can a lot be gain going with 2x6 walls vs 2x4 ext walls? Giving it some thought to justify the added expense as far as insulation concern. Yea I would love spray foam but that’s out of this poor mans budget

Not in Humble. Not worth the expense IMHO. You have more humidity issues than cold or heat. I can cool my shop in west Texas with a couple of good window units and I'm way hotter in summer than you are, temperature wise.

 

[tros]

We did our house with 2x6 walls and foam walls we also did the garage 2x6 walls 16 on center .They both are easy to heat up in northen Michigan. The out side is 3/4 sheathing with vinyl over it so is the garage .We have a 2nd floor in the garage . We built in 2017befor the prices went nuts .

 

[TractorJeff]

FWIW: My Local Building/Zoning requirements state the walls need to be 2x6 if they are over a certain height (10 feet?).

 

[billconner]

FWIW, rrom 2018 IRC: 2x3 - 10', 2x4 and 3x4 - 14', 2x5 - 16', and 2x6 - 20'. There are exceptions.

 

[MongoTA]

Air sealing and thermal bridging are two significant issues. Nothing new by stating that.
If 2x4, I'd recommend 16" OC if allowed and 2" XPS rigid foam board in the exterior. Set the sheets tight and tape the seams, or gap the sheets by about 1/4", use canned foam to fill the gap. Very tight.

Use vertical furring strips over the foam, screwed through the foam and into the studs. Siding gets fastened to the furring strips. Essentially a rain screen. Properly detailed you'll get great thermal performance.

If 2x6, consider 24" OC. Lay out your windows so a king stud naturally falls where a wall stud would. You can do that with the 2x4 wall mentioned above. Doing that plus efficiently framed corners will save a few sticks of lumber, but also minimize thermal bridging.

Spray foam can be out of reach $$, but dense-packed cellulose is affordable. And with a bit of practice at the start up, it can be done DIY. And it performs a helluva lot better than FG batts.

Another alternative for thermal bridging is frame your wall conventionally then add horizontal 2x2s on the interior side of the wall. Space the 2x2s 16" vertically. Net the interior then blow in dense packed cellulose behind the netting. Thermal bridging is minimized, dense-pack is so much better at minimizing air infiltration than FG, and it deadens sound transmission better as well.

Myriad ways to skin this cat.

 

[billconner]

I second everything Mongo said. Dense pack cellulose, continuous insulation on exterior, rain screen, etc.