A program or web page that will design the wall stud size for you?

Question

Has anyone ever come across a program or web page that will design the wall stud size for you?

Say you have a basement wall and it is carrying 22 feet of floor load and 38 feet of roof load, the wall is 9' tall and is sheathed with 7/16" OSB with standard nailing.

I want something that will tell me what size the studs in that wall should be to meet IRC2006 code. I know there is a table in the code book but it's only applicable if the spans carried are 12' or less and that is rarely the case.

Is my question poorly worded? I don't understand what 50x50 or 100x100 has to do with anything I asked. Is there some industry standard I don't know?

I am a structural component designer. We have an engineer we can hire if need be, but most building inspectors do not require a stamped set of plans to give someone a building permit. The example used is a case in point. This builder has the slab down already and a bulding permit. He wants to use a 2x4 wall and I think it should be 2x6 but, I don't have the calculations to back up my assertion.

Answer 1

No. I haven't seen one that designs wall studs.

Archangel, if it is not listed in prescriptive code, you need an engineer to size the wall for you. A 38' span on a roof is near the 40' limit for prescriptive design already. Portions of the building that do not conform to the prescriptive design limitations of the IRC require engineering design for the portions that don't meet the prescriptive code (sometimes called partial engineering, IRC 2006, R301.1.3.).

If the IRC tables don't give you a wall size required for a 9' foundation wall (wood, masonry, or poured concrete), supporting 38' of roof load and 22' of floor load, well, you need to hire an engineer, because the prescriptive code does not give you a value for it.

The prescriptive code is intended to give reasonably safe designs for reasonably common (previously constructed) situations. Your situation, if it is not covered in the IRC, is not common and thus partial engineering is required.

A program or web page may help you get a preliminary size (or IRC Table 602.3(5), and there are a lot of requirements behind those tables, like snow load , 25 psf), but if you are going to get a building permit, and normally that is a requirement before you start construction, you are going to need an engineer's stamp anyway. You also need a wall foundation sized.

Didn't see your added comments when I first responded -
To confirm, when you say span you mean it is 22' bearing wall to bearing wall (points of support)? Your added comments seem to make me think this is a 44' span, in that case, there is no way you can use the IRC to validate their claim, so they need an engineer. They are building a structure that does not conform to the IRC and they need an engineer.

Short answer (if the span is 22' between supports, wall on each end, meaning about 11' of the floor load goes to each wall):
Whatever the IRC tables show for a wall stud size is in that table, R602.3(5) - a 2x4 at 16" or 2x6 at 24" is mandated (roof+ceiling+floor), so if they want to use a 2x4 wall @ 24", they need to hire an engineer to prove it works.

If you're a structural component designer (which I suppose means you don't have a 4-year engineering degree) you need to stay away from calling yourself an engineer (just a friendly so you know), and you also need to avoid doing structural design. Structural design is anything that doesn't fit within the IRC or section 2308 of the IBC. If you provide designs without conforming to the IRC, you're performing structural design, which exposes you to legal fines/penalties as well as you and your company to liability if something falls down.

If the building official in the area has a clue, he can shut down the job if he determines the building does not meet the IRC prescriptive limits (without a stamped design/letter by an engineer).

The building official not requiring a stamped plan yet for permit does not absolve you/the contractor of ultimate liability if you 'know better.' You at least, do know better, because you're asking for help. Like the off-duty lifeguard who refuses to help a drowning man, you are exposing yourself to liability if something goes wrong.

Either explain that it doesn't meet the code (if it doesn't) and get the building changed (floor span reduced to meet the IRC , move an interior bearing wall, put in an interior bearing wall on the lower floor), or play your last card, and contact the building official and get the job shut down until they have an engineer's approval/calculation showing their proposed 2x4 wall stud spacing is adequate. From the sound of it, this is one of those classic projects where they build inadequately and then seek approval after the fact, particularly once they've got the wall sheathing on and nothing can be verified. If they get that far, no engineer is going to be excited about certifying it, and without the engineer's stamp, the building official can order it torn down, (worst case scenario). It is worth the builder's investement to get a designer (like you) or an engineer involved BEFORE they construct to avoid situations like this (It can save them money, too).

Answer 2

You want to avoid making people scroll side-to-side to see the page. 800 pixels is the narrowest screen you are apt to encounter, aside from handheld devices, but that's another issue entirely. You'll notice that Yahoo! Answers uses a page that is just 750 pixels wide, padded with borders on wither side. You can design for a wider screen, but it's best to make sure your pages will re-size to 800 wide legibly and without horizontal scrolling. The majority of monitors today are either 1024 or 1280 pixels wide, but you're under no obligation to fill the whole screen.

Answer 3

Why bother calculating it? Just use 50x50 ...... Or 100x100 if there's a floor on top (but you shouldn't have another floor on top of a lath and plaster wall anyway).

(*EDIT*) 50x50 and 100x100 are standard timber sizes.

(*ANOTHER EDIT*) If your plasterboards are 800 or 1200mm. wide, then space the studs 400 apart. If your boards are 900 wide then space the studs 450 apart. If your boards are 1m. wide then space the studs 500mm. or 333mm. apart.