IRC code for window placement at corners

[buildbetter]

I got a rejection from the building department today because I had windows for a porch we are going to enclose as a three season room within 8" of the corner. We have done alot of porches with windows all around and I have never had this problem. They didn't tell me the code number they were quoting, but I can't find it. Anyone who can give me some insite about how the new code is going to affect sunporches would be helpful. The permit person said I had to have 24" of wall on each side of the corner windows which will block lots of view and air. Thanks alot and hope to hear some good advice.

Lynn

[Dutchman]

Perhaps you had a door near the corner?

Did you submit a drawing for permit, then they failed you at inspection?

Seems fishy to me, I put windows tight against corners on every job!

[buildbetter]

We went in for a prliminary review of our plans to get the permit. The room is 22' long and the door is in the center. The new code calls for 24" of solid sheathed wall on each corner , both sides of corner.

[Dick Seibert]

Corner fenestrations are prohibited under the proscriptive code, see attached Figure 2308.9.3 of the 2010 CBC (which is from the unamended 2009 IBC). I do it all the time but everything do is engineered.

[dlhunter]

I went over this exact thing with an architect not to long ago but can't remember the exact code. There's a way around it but the added cost of doing so made us opt to move the window in. Check 602.10

[Dutchman]

Hmm, well, we're still using IRC 2009 here. Perhaps I'll have difficulty on my new project. Or, like Dick mentioned, engineer.

Whatever the case, don't let them push you around, find a way.

[dlhunter]

I think you need to have a braced wall section on the opposite side of the window opening at least 24" wide and continue the window header to fully extend over that braced wall section. Add some Simpson staps and a crap load of nails in the plywood. I think there may be an exception if the porch wall is less than 8' off of the house as well.

[Dick Seibert]

Hunter:

You either follow the proscriptive code or have it engineered, there is no half way.

[Happy Home]

http://www.woodbywy.com/literature/wb401.pdf

http://www.fairfaxcounty.gov/dpwes/p...ng_handout.pdf

[dlhunter]

Dick,
I wasn't giving an exact design by any means just trying to regurgitate what I was told by an architect six months ago. Not trying to do it half way by any means. Obviously the safe bet is to have it drawn by an engineer.
Lynn, check out figures R602.10.1.4(2) and 602.10.1.4.1 in the 2009 IRC book.

[Dick Hackbarth]

Buildbetter:
The problem or issue is one of lateral load/corner bracing. And, we usually think in terms of at least one sheet of osb, or some such, in each wall plane, at a corner, to provide min. bracing for that wall to react wind load (or EQ loads) picked up by that wall. The pdf that DickS provided shows the code situation. The links that HappyHome provided show various solutions or alternatives. I just glanced at these, but they should clarify the issue for you. The wall bracing can be provided at other locations, and by slightly different means, but you can’t just let that corner hanging out there, unbraced. And, someone has to show these load paths and that you get those loads down to the foundation. Dick has it engineered because of Calif’s. stringent EQ requirements, generally more severe than wind loads. High wind areas would require special attention too. With the latest code eds. you will have trouble building a porch with all windows on all three sides, without some very special engineering.

[Top Notch]

The amount of shear wall panels and size of the panels has been beefed up in the code. There are all kinds of opening triggers, blocking and hold downs needed when big openings are used. Its a complicated section in the code.
My guess would be they are starting to ease everyone into it during remodels. Obviously existing windows have been fine for a long time and direct replacement is allowed but an alteration brings opportunity to get compliant.