Where are you guys coming up with needing 2x6s on the first floor walls of a 2 story building??? Although, not in the last 7 years due to back problems, I've never built a house or any other building with 2x6 walls unless the customer wants them for insulation depth. (And, yes, it is no fun lifting up the end walls made out of 2x6s) If you build with 2x4s, with wind braces in the corners, and plywood sheathing nailed according to code, it's not going to come down without some serious effort.

 

Moose Iam looking at the International Residential Code book.
Table R602.3(5)
Size , Height and Spacing of Wood Studs
Maximum spacing when supporting one floor, plus a roof-ceiling assembly or a habitable attic assembly - 2x4 wall framed 16" o.c. Only where the roof spans are less than 32'. Roof spans over 32' studs shall be increased to 2x6.

Beergut There are many reasons why you might be required to use 2x6 insted of 2x4. For a house you are better off using 2x6 because of insulation. You will have or the potential to have a better R and U value.

 

So, this isn't mentioned in the Mass. Blue Book. I'm taking a refresher course that the state is requiring in June. Only keeping current to do contracting in the future but not the labor part. With spans like you're mentioning you'd need trusses or plywood beams with the exception of a 2x12x18 with a 34-36' wide house spaced every 12". I believe you can still use a 2x4 wall for that but not 100%.

 

Moose you might be right. I just finished the test prep class.

Table R602.3.1 Maximum Allowable Lenght of Wood Wall Studs Exposed to Wind Speeds of 100 mph or Less in Seismic Design Categories A,B,C,D0, D1 and D2bc.
Supporting two floors and a roof >10' 2x4 can be used if framed 12"-8" O.C
Supporting one floor and a roof >10' 2x4 can be used if framed 16"-12"-8" O.C
I think I read the Table R602.3(5) wrong.

You have to love all of the amendments MA. puts in the "blue book".
Its knee walls would have to be 2x6 providing your attic has a floor.lol This was good practice for the test.

 

when I was going over the prints with the architect- he said I had to use 2x6 on all the exterior walls- first & second floor- said it was building code... maybe because I have high ceilings and no collar-ties

there was also some weird code dictating the insulation value of window space vs. wall space Don't remember it being like this when I built my house 12 years ago...

 

Shouldn't have anything to do with collar ties. Collar ties are just to keep the tops of the supporting walls from blowing out from the ridge collapsing downwards. If you don't have roof trusses you either have to put in collar ties or ties at the top of the supporting walls from one side to the other.

I think what they're getting at is if you have lots of windows you are losing a lot of insulation value and you need to make up for it by incorporating a thicker wall. Never heard of it but this is kind of what I think they're getting at.

 

That's probably why I need the refresher course.

 

Is it going to have a cathedral ceiling? All of the cathedral ceiling/roofs we have built require a structural ridge. Usually a 4 gang beam made up LVL 1.75x24" and most of the time 30'+ long. FML they are heavy. Sometimes we even use LVL for rafters . So if you have a structural ridge it has to be posted on the ends. If that is the case the amount of bearing is a important factor, thus 2x6 walls. Most architects will spec out the post material, insted of 2x6 studs they will want 2x6 LSL continuously posted to the foundation.
In ma. a new house or addition will have to meet standards. You cant build a house with no insulation, even if you wanted to. Windows are taken into the equation. So they have to meet standards.

 

There is so much info in those books. Iam studying the commercial and residential. Its hard not to mix them up. Then the plans I have at work.... When my wife asks me a question about anything all I can bring myself to say is "Ummm Yes?" Not the best answer....

 

If anyone needs any professional drywall advice let me know, I have been in the business for over 25 years