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CabinRookieWNY
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# Posted: 16 Jun 2013 08:34pm
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Wondering if anyone can provide some insight on how big of a header I need to span a 10 foot opening. I am knocking down the middle wall in my cabin to open up the space. I am thinking of talking 3 2x8x10 foot boards and create the header to cross the span. On each end, I will double up a couple 2x4's to hold these up. Is there anything I need to be aware of to do this? the roof beam trusses will sit on to of the header I am installing. I'll need to build a temp. support on each side until the header is up and in place, but I really don't think it should be all that difficult. I just want to make sure the header will hold the weight. Any advice would be most appreciate. THANKS!
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Martian
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# Posted: 16 Jun 2013 11:27pm
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If you truly have trusses, they should be self supporting.
Tom
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toyota_mdt_tech
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# Posted: 17 Jun 2013 12:39am
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Do you have trusses or rafters??? If its trusses, then like the other said, self supporting. If its rafters, they load the outside walls. The ceiling joist or rafter ties do not really load down, but need support to hold themselves in place IE their own weight and what on them is about it. I suspect you may not even need a temp support. Just remove the studs, add the header. How long is your span or opening going to be????
What are your cabins dimensions, what is this wall holding up now, ie 12 foot 2X6 etc? Is there a loft?
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CabinRookieWNY
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# Posted: 17 Jun 2013 05:45pm
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So the cabin is roughly 25X20 as seen in the picture, I will be removing the wall on the left side of the pix. Guess I don't know the difference between a truss and a rafter. I thought they were the same things. The wall which will be coming down had those beams across from that outside wall to the middle and conversely, same thing in the other room. The span will be roughly 10 ft across starting at the wall on the left side and down 10 fee to another main center support column that is basically the center of the cabin. As I read your post, I believe I have 'rafters' as these come from the outside wall and are supported in the center. The wall there now is quite flimsy and there are maybe 5 2x4's supporting the load. There is no loft in this area, but will be one on the other side over what is an existing bedroom and bathroom area. I will beef up the supporting structure there as well. Any further details would be great. I appreciate the advise. Is 3 2x8x10 too much, can I get away with 2. I will get more pix next weekend when I get back down. Thanks!!
Wall coming down to the left
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WY_mark
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# Posted: 17 Jun 2013 07:24pm
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google "header span table" - choose your type of wood and the span needed for load bearing applications.
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CabinRookieWNY
Member
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# Posted: 17 Jun 2013 08:25pm
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WY_Mark,
Thanks.. will give a search. That stuff is usually too confusing for me. Not a PhD. in mathematics, but the process to figure, well... nuff said.
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WY_mark
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# Posted: 18 Jun 2013 12:46am
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it's simple, take the span you have to cover - 10' trace down the kinds of lumber available to you and it will tell you what size header you need. No math involved, just trace columns of numbers with your fingers till they meet.
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bldginsp
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# Posted: 18 Jun 2013 07:59am - Edited by: bldginsp
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Sounds like this wall is supporting nothing more than the ceiling joists. If this is the case you can do this project as you described with a simple header. But, if that is not the case and this wall is part of the roof support system, you need to be careful. I doubt that it is, but you need to confirm this. If your header will be taking significant weight, it needs to be sized properly for the span, and, the supports for the header need to send the weight to the earth rather than onto floor joists.
I think your project is simpler than this but I can't tell from your description so I'm just letting you know the 'what ifs'. I suggest you get an experienced builder in to look at it for you, just because you aren't familiar with this kind of thing. He'll teach you a lot in 10 minutes by just pointing.
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ICC
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# Posted: 21 Jun 2013 10:21pm
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I can not accurately decipher what you have from the dark picture and the verbal description.
If the sloped 2x's in the photo are the rafters the roof is very shallow pitched. Too shallow a pitch to stay together without the wall being s structural component. Are those the rafters or are those ceiling joists? They appear to be sloped or maybe it's just the picture angle. Is that wall down the center of the building? If so it appears to be holding up the ridge of the roof.
To determine a header size requires knowing roof load, snow load. Is there an attic/loft? What is under the floor? Sizing and installing a header is one part; the other is sizing the columns or posts that supprt the header as well as assessing what is under the floor at the position of the columns to take the load and transfer the load to the ground. There is more here than sizing up one piece of the structure.
I ditto bldginsp idea of consulting with an experienced builder.
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Martian
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# Posted: 21 Jun 2013 10:33pm - Edited by: Martian
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I see what appears to be 2X6 ceiling joist. If they span the cabin, they will support themselves while you install the beam. Just be sure and put a level, or string line, on them when you measure your jack length; so you can take out any sag.
Tom
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ICC
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# Posted: 21 Jun 2013 11:25pm - Edited by: ICC
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Quoting: Martian f they span the cabin, they will support themselves while you install the beam.
I'm not sure that with that low a pitch, I would want to put my faith in some unknown (?) builders work, but then I worry about that sort of thing. Yeah there probably won't be a collapse right away when the wall section is removed but I'd rather take time to use temp supports than have to do more rebuilding later. Gable roofs with pitches of 3/12 and less are not covered by the rafter tables in the IRC.
20 feet wide. IF that is a 3/12 pitch and if we figure the dead load (roof materials weigt as 10 psf and if the rafters are 24" OC the outward force on the wall is 400 lbs at each rafter tail. 16 inch OC that becomes 266 lbs at each rafter tail. How good are those connections?
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Martian
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# Posted: 22 Jun 2013 12:11am
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ICC, how does removing the center wall effect the tensile load bearing capacity of the ceiling joist? 
Tom
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ICC
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# Posted: 22 Jun 2013 12:56am
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the picture is so poor (dark) I am not sure what I'm looking at.
are those joists? or rafters on a low pitch roof? Looks sloped to me but that may be the way the camera was held. i don't think any of us knows enough about how that is put together to make a safe guess as to what can be done.
i suppose i should keep quiet when the facts are murky... just hate seeing someone cut away something without them being darn sure about what they are doing.
overcautious Ike.
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