wood stud analysis & other 2x4 vs. 2x6 stud considerations 2

[eng003]

Although building codes and design guides i.e. wfcm (even for higher wind areas) often permit 2x4 exterior load bearing studs up to 10 ft in height for single story applications...when I analyze them I often find them over stressed under combined wind and gravity loads. I am interested in what others have found?

I have seen composite sheathing action discusses...any thoughts on this? I saw in one thread a building code permitted a stress increase for composite action? anyone no what code and where is this permitted by?

Apart from taking away my strength concerns what other advantages of using 2x6 instead of 2x4 studs can I list to clients?

 

[OldPaperMaker]

eng003,
Someone pointed this out recently: The American Wood Council, Special Design Provisions for Wind & Seismic, Section 3.1.1.1 referres to Table 3.1.1.1 which gives the Wall Stud Bending Stress Increase Factors for various stud sizes. This System Factor ,which is used lieu of the 1.15 repetitive use factor,is 1.5 for 2x4 & 1.35 for 2x6.The factor applies when studs are spaced no more than 16" o.c., covered on the inside with a min. of 1/2" GWB and sheathed on the outside with a min. of 3/8" wood structural panels that are attached to the studs using a min. of 8d nails @ max. 6" oc at panel edges & 12" o.c in field.

The other benefit of 2x6 over 2x4 studs is that you can get a higher R value of insulation batts in the 2x6 wall.

I hope that this helps.

 

[msquared48]

Also, when the electrician and plumber get through drilling their holes, at least some of the stud is left with the 2X6 stud.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[shobroco]

And there is a slightly better chance of the studs remaining relatively straight as they dry.

 

[port125]

Those are all structural reasons, people (typical home owners)don’t care about.
Tell them that a 2x6 wall is a little thicker and will make the door jambs a little thicker A little thicker jamb looks better and will make the house look more elegant/grand. All of their friend’s will be jealous of the awesome house.

 

[Cadair]

You will get less usable space with 2x6 walls than 2x4. The newer energy codes are pushing towards the 2x6 or foam.

 

[MiketheEngineer]

I think you can go to 1.6 for wind loads. But I like 2x6 walls and see more and more "upscale" homes - even 1200 sq ft using them for all the reasons listed above.

 

[dicksewerrat]

I was working under the impression that 2 x 6 was the only way to go for exterior walls.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com