2x4 or 2x6 studs

[Preston]

Just wondering about people's experiences and reasons for choosing one over the other.  We're wanting to build the 20' wide 2-story cottage.  Any thoughts???

-Preston

[PA-Builder]

I used 2x6s (on 16" centers) and feel it was a good decision.  

Pros:  Stronger.  Less warping & a better quality stud was available, more room for insulation, plumbing, electrical cables.

Cons:  A little more expensive, but not enough to consider going with 2x4s, a little heavier to work with, but no big deal.

[Preston]

I used 2x6s (on 16" centers) and feel it was a good decision.  

Pros:  Stronger.  Less warping & a better quality stud was available, more room for insulation, plumbing, electrical cables.

Cons:  A little more expensive, but not enough to consider going with 2x4s, a little heavier to work with, but no big deal.

Any reason you stayed with 16's instead of 24?

[cedarglen]

I am currently building the 20' 2 story with 2x6's 16 o.c. Here in California the building code won't allow less. In most places you can probably go 24"o.c. with no problems. Structurally I don't think it makes a big difference.

Chuck

[MountainDon]

We're talking exterior walls, right? 2x4's will do nicely inside except for some walls and plumbing requirements.

Interesting question and one that has been and will continue to be debated. The usual reason for choosing 2x6 over 2x4 is to get the extra insulation. However if you're a sloppy builder you may have more air infiltration in a 2x6 wall than a careful builder with 2x4's.

Proper sealing against air filtration, under the sills, in the corners, around plumbing and electrical penetrations, ductwork, etc. is at least as important as more insulation. Air moving within a wall will have heat moving from one place to another and usually in the direction you don't want.

If you use 2x6's you can increase the stud spacing to 24" in most locations instead of the traditional 16". But if you do that beware of trying to use 1/2" drywall on the interior. You'll end up with wavy walls. Use 5/8" or other more rigid wall materials.

The wider spacing does have the advantage of increasing the effective avergae R-value of the wall as the wood stud has a much lower R-value than the usual fiberglass batts. Fewer studs = more fiberglass.

2x4 walls with fiberglass batts plus a 1 to 1 1/2" layer of foam board on the exterior is another good insulation technique. This has the bonus of limiting the thermal leakage thru the studs as well as providing an air barrier.

2x6 will cost more; more wood, more insulation, windows & doors may cost more or extra dollars to extend the jambs... but there will be a payback in energy savings over time.  

Another factor to consider is whether or not your building must meet the Dept of Energy, International Energy Conservation Code. It much more difficult, maybe impossible, to meet it with conventional 2x4 exterior walls. Check with your permit/code/inspection dept first. The answer as to what to use may be dictated by their rules.   http://www.energycodes.gov/rescheck/

[Preston]

Thanks for the great link MountainDon, how is installing siding over the rigid foam?  I won't be using vinyl, probably a traditional slat or t&g siding.  To make sure I understand this, the foam would replace the plywood sheathing and you would then want a vapor barrier between the batting insulation and the drywall?

[MountainDon]

The example I saw recently had the usual 7/16 OSB installed as exterior sheathing with the 1" extruded foam over that. Then it was stuccoed. The interior was drywalled.

Siding would need longer fasteners to be used. Depending on the materials being used you might have to be careful about crushing the foam.

I've also seen articles where the foam board was applied without the OSB or plywood... not sure if that was some special kind of structural foam or not.

Information re building better, higher energy efficient homes may be found at http://www.buildingscienceconsulting.com/index.html
There are lots of variations as examples. Choose by basic weather type on this page. (specific as built homes shown down near the page bottom.
http://www.buildingscienceconsulting.com/designsthatwork/default.htm

One caveat. They show a different inside corner framing method that uses clips for securing drywall. In practice they are less than an ideal drywall securing method.

[glenn kangiser]

OSB or plywood may still be required for bracing - at least on some areas.

[MountainDon]

OSB or plywood may still be required for bracing - at least on some areas.

As always.... check with the applicable officials.  :-/

[tjm73]

To meet most code required R values 2x6 is pretty much a neccesity for an exterior wall.

[MountainDon]

It really depends on how the locals have written their version of the gospel. Some governing bodies have mandated that nothing less than 2x6 walls will do, no if's ands or buts. Others, like NM, have declared that all new residential construction must meet the Dept of Energy, International Energy Conservation Code 2003. The RESchek program is approved and promoted for determining compliance with the standard. This rule may be superseded locally as long as the changes are no less stringent than the state rules.

You run the RESchek program with your values and print out the data sheet when the program says it's within compliance. The bldg. dept may check the figures, they may not, they're not telling, but that sheet becomes part of the approved plans.

This does give leeway in how to achieve the required energy code. For a ridiculous example; R120 ceiling, R11 walls and R42 floors will get a passing grade even though it may not be too practical. More realistically it's fairly easy to get R38 ceiling, R13 walls (2x4) with R5 (continuous layer 1" foam) for a total R18 and R30 floors approved as long as you are using good windows. (Using a post/beam elevated foundation for this example.) Note the number of windows and their U-factor is taken into account as well as the number of exterior doors, skylights, etc.

I was simply trying to point out that the near automatic choice of using 2x6 walls for better insulation is not the only way, nor necessarily the best way to "skin that cat". Again, the place to start is your local code, then design from there.

[MountainDon]

I ran this a while back for myself, but misplaced the numbers. So, being me, I re-ran the numbers for 2x4 vs 2x6.

I'm basing this comparison of the cost of a 2x4 and 2x6 framed walls on my basic cabin plan size, 14 x 26, 364 sq. ft.  For comparison I've chosen a single exterior door, three windows (one each 6x4, 4x4 and 3x3) and deleted the equivalent insulation area. The framing estimates include the sill plate, studs, and two top plates as well as jack studs for doors and windows. I know there's likely a piece or two of lumber not accounted for but if so, they're missing from both estimates so this should be accurate enough for comparison.

The 2x4 wall studs are assumed to be 16" O.C. The 2x6 studs 24" O.C. Both estimates include 7/16" OSB on the exterior. Nails, sealants, etc. are NOT included. Actual doors and windows are not included either. Pricing obtained from my local Home Depot yesterday.

2x4, 16" OC sheathed walls   $445
2x6, 24" OC sheathed walls   $510
   2x6 is approx 14.5% [$65] more than 2x4

ADD R13 fiberglass to the 2x4 and R19 to the 2x6
2x4, 16" OC sheathed, plus fiberglass insulation   $695
2x6, 24" OC sheathed, plus fiberglass insulation   $810
   2x6 is approx 16.5% [$115] more than 2x4

ADD 1" of R5 foam to the exterior of the 2x4 framing.
2x4, 16" OC sheathed, plus fiberglass insulation, plus 1" foam   $960
   this costs 18% [$150] more than the 2x6 with fiberglass only
   and 38% [$265] more than plain 2x4, R13

Dollar increases are very low compared to the total materials cost of the building shell, let alone the completed cabin.

Of course you could go 2x6, 24" OC, with exterior foam added.
Framing, sheathing, foam comes to $1075   :-/

So right now, I'm leaning towards the 2x4 framing plus exterior foam, as this is for a small three season cabin. Wood stove heat and there's lots of wood. Winter is a crap shoot regarding snow... too much and ya' need a snowmobile. And I'm not a real snow person anymore. YMMV

[Preston]

Thanks for sharing that MountainDon.  I'm leaning towards the 2x6 16 oc with at least 1/2" exterior foam over sheathed walls.  I think this will provide with an insulating factor that should stay pretty current for awhile.  We're trying to avoid (Well I've pretty much decided) no forced air even though we'll be in the mountains.  Taking Advantage of the Passive Solar Tools and SuperInsulation, I think we'll do alright.  We're thinking of using Electric Radiant Floors as well as at least 1, maybe 2-3 Fireplaces for heat when it's needed.

Neat to see the differences once again!

[Redoverfarm]

Preston nothing against Don but I am with you. I found it alot easier to work with 2X6 when it comes to wiring, plumbing and the like. Also it gives a better nailing surface when building walls. If I were to build another two story as I did a couple of years ago I would opt for the 2X6. It just makes me feel better when I am sleeping on the second floor.

[raybob]

With 2x6 at 24" OC, you don't need headers for windows that have a 22 1/2" rough opening.  A *big* money saver.

Bob

[MountainDon]

A *big* money saver.

Well, Yes and/or No.

Even if you can do that, it seems to me if you end up installing 2 smaller windows in a space/room where a single larger window might also be used, you will spend more on the 2 individual windows than you would spend on one larger window plus header materials.

Just my opinion.

[Preston]

Bob, I can see what you're saying, however in my case we're going to be doing larger windows.  It's definetly something to consider.  I don't really like drywall, so thinking about a heavier/thicker piece of that stuff makes me cringe.  I've done a lot of it so you think i'd get over it.  I'd do 3 entire roofs to 1 room of drywall.

[raybob]

A *big* money saver.

Okay, okay.  I think the money saved per window might roughly approximate the grocery store sticker on the malbec I was nursing when I wrote that.  Still, no cripple studs, no jack studs, no headers, no weakened load bearing studs.  It's got to be easier and simpler.

Bob

[MountainDon]

It's got to be easier and simpler. Bob

I guess I can't argue with that, Bob.

I see the choice of window size, window type, and window location as a purely personal decision, except for the demands of meeting code. Other than code restrictions, there is no single right way to do windows. On a purely personal basis I don't see the designing and building of headered windows or doors as a problem. I enjoy the design process. I enjoy the satisfaction derived from the challenge of accurately translating the drawings into the finished building. I would rather put a little more effort into the whole job and end up with a finished product that fulfilled my needs or desires.

I have a great view available to my cabin. I see no point in skimping on the window size. I paid for the view. Certainly that 6 ft x 4 ft window is going to be a heat hole. No argument there. But it's more economical to me to do that one large window than to have three narrower windows. I want the view and the daylight it will provide to the interior, more than the higher thermal efficiency of a solid wall, or a single small window, in that position.

I guess my real point is that in my 61+ years of living I have made some decisions based purely on the immediate economic cost to me. I have regretted some of those decisions later. I try to achieve a better balance of immediate cost, future cost and personal satisfaction with the results. I mentioned somewhere on this forum that I will also be building shutters, probably insulated, for the cabin windows. I will have the option of having them open or closed. Again, not the cheapest way to build the walls and windows, but one that will give me the best compromise including my personal satisfaction and happiness. IMO.

There's an old British saying, "penny wise, pound foolish" [the "pound" being their currency before the Euro.] I believe it applies to many things in life.

'Nuff said... just a personal view on walls and windows.

[FrankInWI]

I'm just finishing roughing in our place.  My arthrites made me hire a few laid off framers for three days work.  Anyway, I went with 2 X 4s.  Mostly cause it was just easier and I saves me some space.  I can only use 50 of my 100 wide lot for building, so for a garage and future 1 1/2 I need it all.   Plus...what's with the safety issue?  Think it's not founded.  "I would opt for the 2X6. It just makes me feel better when I am sleeping on the second floor. "  I live in Wisconsin, and I can't remember ever hearing of a house "falling down".  Tornados take em all out like there toothpicks....so
Anyway, I went with 2 X 4 and was only going to sheet the corners with OSB.   I changed my mind and sheeted it all (did feel I needed to do that for safety....givin the big top this garage has!  We are just finishing up sheeting the whole thing in 1" DOW.  I didn't approach the decision too scientificaly, I just wanted the thermal break outside the studs like my city house has.  

[MountainDon]

Looks like you ended up with what I've spent much time deliberating about, Frank.  

..what's with the safety issue?  Think it's not founded.  

Back home I grew up in a neighborhood full of 1 1/2 ti 2 1/2 story houses, stick built with 2x4's Never saw one of them fall down either. They're now 100 years old and for the most part still there, but mostly updated, renovated, ext. foam added, etc. But underneath the same old, same old.

G/L and I hope to see some pictures when you can.

[John_C]

OK I'll play devil's advocate.   I'm seriously thinking of using 2x8's.   Locally a 12'  2x8 is only 25¢ more than a 12' 2x6.  The 2x8's are really nice southern yellow pine and the 2x6's (and 4's) are poor quality spf.   It winds up being a couple hundred buck's and the added insulation can't hurt.

I want the next house to be very well insulated, but the primary motivation is the sorry quality of the spf .. whitewoods framing lumber.

[glenn kangiser]

Ken Kern mentioned that 2x4 stud houses were already overbuilt.  A 2x4 will support much more than the little bit it is called on to support in a stick built house.  

[MountainDon]

Funny you should mention.... John C.

Just today I saw a truck/flatbed rig parked with a load of what appeared to be pre-fab wall sections. They were mighty thick looking. I went over and discovered what appeared to be a knock down house. Framed with  2x10's!!   , sheathed with OSB and those black fiberboard panels. 8 foot sections. I couldn't see the sides to see if they were cut out for windows or doors or if they were insulated in any manner. It was a NM transport, but have no idea where it was going or coming from.

[ScottA]

Interesting debate on this issue. I've worked on dozens of houses framed with 2x4's and never really saw an issue with them. A 2x6 house more solid when you slam a door and is quieter  I'd say due to more insulation but if you live in the woods that's not really an issue anyway. The gain from R 13 to R 19 is like less than 1% so I don't see why all the fuss. You'd do better to sheath with foam which creates a thermal break at the studs. As small as most of the houses people here are building you won't save much on your bills by going from 2x4 to 2x6. I'd put the insulation in the floor and the roof or buy better windows if it was my money.

Scott