Framing Question 20x30 1.5 story

[Josh Meier(Guest)]

I have a question regarding the stud size. Are the 2x6's used primarily for the ability to increase the insulation r-value from 13 to 21? Or are they required structurally? Sorry if this is a somewhat ignorant question, but if you don't know, you gotta ask.

I bought the plans a few weeks ago, and am getting ready to put subfloor down. These are great plans, I could put my entire scrap pile to this point in a five gallon bucket!. Thanks,

Josh

[reverendxlt]

hmmm... :-/ was it really that bad of a question?

[Jimmy C.]

My guess would be...they are needed for the structural integrity of the walls because of the additional weight of the second floor and items you would place up there. The extra insulation is a side benefit!
I also think it is easier to balance a 6" wide wall standing up than a 4" wide wall.

[Amanda_931]

Seems like, back in the 70's, people were interchanging 16" on center 2x4 framing for 24" on center 2x6.  On the grounds that the latter cost a bit less to make, had room for more insulation--with less thermal bridging, and were so close to the same strength that it made no difference.

[highlight]BUT[/highlight]

Now, guys, e.g. PEG, who are in the business of building now think that the best option is 2x6 framing on 16" centers.  Not so much for strength as for keeping it fom being wavy--and they are pretty happy to ignore the extra thermal bridging in favor of a nice solid and straight wall.

So, maybe "neither" is the strictly correct answer.

[glenn kangiser]

Hi Josh.  I didn't answer because I didn't know for sure --- I'm primarily a steel guy, but if I remember right 2 x 4 walls are OK up to 2 story.  I think it's for insulation- but it is unquestionably stronger. John will probably pick up on this shortly.

[PEG688]

It's for the insulation , think of all the old two,  three  houses / appt's  built over the years .

The insulation works for both keeping warm in and cold out and visa versa so to speak in hot places, Az. Tex. etc .  

 There could be [highlight]special situations [/highlight]where 2x6 might be required for structure but in all of John's places shown on this site , although I do not have any plans , I would think we are talking 2x6 for code compliance / comfort issues  / insulation / common sense.

I like 2x6 16" OC for all the reasons Amanda mentioned , I never bought into the super insulated building line of thought , skinny up on framing , etc .

 So to be brief , which I seldom am   IMO needed for insulation #1 reason.  

[reverendxlt]

Thanks for the replies. I appreciate the help. I have pretty limited cash resources, but haven't actually done the math on which is cheaper. I know the insulation will pay for itself pretty quickly, but I am also trying to get this house built ASAP. Been living with family for a year+ with four kids (ages 5 and under).

[dorwin]

I used 2 x 4's on 16" o/c with 12 ft balloon walls and no problems.  See attached photo.

[John Raabe]

Nice job Dorwin!

I designed the framing for 2x6 for several reasons. One is the let in ledger that eats up 1.5" of the depth (discussed in another thread). Then there is the issue of stiffness (beam action of the deeper stud) when you are resisting some outward forces of the roof. Third is the higher insulation. And finally, with a 2x6 wall you could do studs 24" o/c for optimum value engineering if you wished.

That said, there are thousands of balloon framed buildings like this that are put together with 2x4 studs. It is a time honored and proven method - assuming you can get the long straight studs needed.