Does anyone know where I can find a header span table? I’ve googled and searched the archives here and can find plenty of floor joist and rafter span tables but havn’t had any luck finding a header span table. What I need to know is if a doubled up 2 x 12 with a 1/2″ ply spacer is enough to span a 8′ opening. I havn’t determined if it is supporting the floor joists above yet, but am assuming it is. Any help would be appreciated.
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Replies
The first thing you need to know about headers is the span. The 2nd is how much it carries. Without those 2 things no header table will do you any good.
I don't know of any header span tables for conventional lumber. If you just need one header you may be better off getting an LVL. That way you can get the supplier to design it and stand behind it.
And they should be able to provide whatever you need for your local code officials, if you have any.
Code officials aren't an issue here, fortunately. The situation is I have a wall between my kitchen and dining room that I plan on removing. When I stripped the sheetrock off one side of the wall I was surprised to find that the 2 x 12 header over the existing 2'6" doorway continued all the way across the wall, and there was a large opening framed in the wall. Apparently when they framed the house they planned on having an opening in the wall, kind of like a "pass-through" I guess. For some reason they just rocked right over the opening. What I'm trying to determine is if I remove the few studs there are in the wall, will the header be OK or will it need a support post somewhere along its length? As I said in my first post, I havn't determined whether the header is supporting the floor joists above yet (I'll get into the ceiling this evening to see what's going on) so maybe this discussion is premature. Thanks for your reply though.Andy
Common sense says that if the ends of the header are properly supported on jacks, then you are probably OK....unless the reason the original designed for pass through got nixed was a problem with the header!
The thing with headers is that there are way too many variables involved to condense the whole matter into a few simple tables. It can only be reduced to tables for the simplest and most common cases. Anything with a floor load on it is better calculated case by case.
For the simplest and most common cases, there's a rule of thumb that sometimes gets expressed as a table:
If the span of the header is no more than 12 ft, and the load on the header is only an ordinary ceiling and roof (no extra heavy tile), and the total span of that ceiling and roof load is no more than 20 ft., Then .....
The depth of the header in inches should be no less than the span in feet.
That'll do it for windows and doors in the outside walls of not so big one story houses, which is a lot of headers. The rest need some intelligent thought applied to them.
-- J.S.
Actually the IRC does not have any problems putting a header chart in it's code.Just has lots of rows and columns for all of the parameters.
> Actually the IRC does not have any problems putting a header chart in it's code.
Thanks. That makes me even happier to be in UBC territory. ;-)
-- J.S.
"Thanks. That makes me even happier to be in UBC territory. ;-)"Just realize that UBC is obsolete and being replaced with IBC.And the IRC is just a reduced version of the IBC (and the other code IPC, NEC, etc) with the info needed for 1&2 family homes.
>> don't know of any header span tables for conventional lumber.
The IRC contains header sizing charts for sawn lumber, and they're very easy to use IMO. The building department here passes out a copy of the IRC charts as part of every permit they issue. There are charts for different loads... supporting a roof only, supporting a floor above and a roof, etc., and for different snow loads.
I didn't know that - But I've never seen a copy of the IRC. Seems like it would be difficult to cover all the loading possibilities from all over the country.
It is better to be making the news than taking it; to be an actor rather than a critic. [Winston Churchill]
The rule of thumb around here used to be 1 inch of header depth per foot of span (doubled 2x6 for a 6' opening, 2x8 for 8', etc.). This was to support 1 floor load or 1 roof load. For a floor and a roof, use the next size up. So a double 2x12 could support a 10' first floor opening with a second floor and roof load on it.
Granted, this is a rule of thumb only, doesn't account for concentrated loads, but plans review and inspectors were generally happy with it.
I strted to reply in that groove,too, but that's for single- story ---no live load above
In case anyone was wondering what the outcome of all this was, here goes. I opened up the rest of the wall and part of the ceiling and found that the header was not continuous, but was broken between the existing doorway and the wall I removed. The part of the header that was buried in the wall apperently wasn't doing all that much as there was a 1/4" gap between the header and the top plate and another 1/4" gap where the header should have been sitting on the trimmers. The floor joists above on one side of the wall are running parallel to the header. On the other side of the wall a couple of the joists in the middle of the rooom are perpendicular to the header and then they are headed off with a doubled up joist and run parallel to the header for the outer part of the room. The ends are sitting on an exterior bearing wall, and the parallel joists are only about 5 feet long. So, it looks like the wall is only bearing a small part of the floor above, along with a partition wall that is in the room above. I took out the headers and the king studs and cut out the top plate so I can run the ceiling straight across the room. Basically, there is one 2 x 10 x 8' lenght of floor joist carrying the partition wall above and the small section of the floor above. There is no noticable deflection when someone walks and jumps around in the room above. I'm debating doubling up the floor joist that is carrying the load, but am not sure if it is really necessary. So, two questions: first, does the above explanation make any sense at all, and second, am I crazy to leave things as they are or should I add another floor joist?
Here you can download a copy of the 2000 IRC.
http://support.broderbund.com/download_desc.asp?dlid=384
It self expands into a series of PDF files.
It has a header chart in it.
Look under FLOORS, not walls.
Thanks. The attachment is exactly what I was looking for and I'm sure will be very helpful.