sizing a header

[Deuce1]

I would like to create an opening in a wall, (approx. 9.5 ft.), in a downstairs wall on a two story residential house. The upstairs floor-joists lap above the area of the prospective opening. There is a 2x4 interior wall above this same area and ceiling joists for the upper rooms lap also above this area. But there is no roof supports of any sort above this area. The walls are sheet-rocked, and on either side of the new opening are two 32" return-air chases. How can I go about sizing the header for this new opening. I have been a carpenter for some 30 years, but have always relied on lumber tech to tell me what I should use. Is there a sizing calculater, (so to speak), that will help me size the header myself? Or can someone advise me what header will SAFELY carry this span? I am more that comfortable in supporting the downstairs ceilings temporarily, while cutting the opening. I just need to know what size of header or lamenant beam will carry this opening.
I appreciate your help....Thanks Ron

[Bill Lacey]

Re: sizing a header

If you go to WWPA.org, there is an Excel file that has all sorts of lumber calculating functions in it (Design Suite, or something like that). Other than that, you have to figure out how many pounds per foot you're trying to carry, and look up a span table to see how many plies of what height lumber you need to carry that load.

If all that fails, go to either a lumber yard or call an engineer.

[Tom Thomas]

Re: sizing a header

Deuce,

The rule of thumb that I learned so long ago I can't remember the source; prehaps Popular Mechanics:6ft span=4x6 or double 2x6,8ft=4x8 etc.
So 4x10 or double 2x10 would be sufficient for 9.5ft.

There is a way to retrofit a header without shoring inside. Once you have the
existing studs exposed, cut out a path for one side of the header only half way through the studs. Then install one 2x10 complete with jack stud. Now
you can cut the rest of the way through the other side and add the other 2x10. It is much easier to work on the inside without the shoring in the way.

Have fun,
Tomoose

[Deuce1]

Re: sizing a header

Thanks so much, Bill. I will check that site out right away. I get so frustrated trying to get info out of lumber yards or finding a cooperative engineer.... Again, I appreciate your quick response and help. Sincerely, Ron

[Deuce1]

Re: sizing a header

That is great information, Tom. That also gives me a good start on my peticular situation. Yes, I have done installations like that before, and it truely works well. I really appreciate your response and help. Thanks, Ron

[TWhite]

Re: sizing a header

Deuce, if it were me, I would use 2-1 3/4" X 12" microlam beams for this size header. The cost is small compared to what might happen if it settles. Also if there are point loads above there is no way a dbl 2 x 10 header would work. Been there before!

[oldschool]

Re: sizing a header

A good lumber yard should have an engineer(s) on staff. They do the sizing for all of the engineered lumber--I joists, LVL, truss joists, etc. I don't know what I'd do without the 2 engineers employed by my local lumber yard (The Contractor Yard, Wilmington, NC). I give those guys numbers and situations all of the time for the additions, repairs, and remodels that we do. They enter all of the conditions in their computer and they spit out exactly what's needed. And that printed piece of paper is what's really important. That's the engineer's seal and he's not going to make his recommendation without being 100% confident in what he's given.

Further, if you want to keep this header from sticking down from the ceiling too far, use LVL for the header. 9 1/2' is a pretty significant span with joists for rooms above bearing on that. Also, you probably don't want this header to be more than typical wall thickness w/sheetrock: 4 1/2".

[O'BrienConstruction]

Re: sizing a header

I'm with oldschool, but it might just be a NC thing. My lumber yard will also size beams for me for free. Whoever published that rule of thumb that Tom mentioned needs to be pushed back under the rock he crawled out from. That is the worse rule of thumb or advice I have read in a long time. Tom I hope your not using that for your projects. I really hope your inspectors aren't allowing you to either. A double 2x10 could never carry the load across a 10' span for a 2nd floor, its furniture and people, the ceiling above and any attic storage that is being used on those ceiling joists.

Ron, take the advice that Bill Lacey gave you and also go to your lumber yard and see what they can do for you.

[charles]

Re: sizing a header

Maybe 15 years ago, engineer Robert Randall wrote an article for JLC on sizing headers that included tables. Even tells you how many jack studs you need at each end.

[James Eggert]

Re: sizing a header

Charles brings up a very interesting point. The IRC codes require multiple jacks as the opening increases.
Check your adopted code!

[Dancing Dan]

Re: sizing a header

Ron - are you really going to size a beam carrying a significant load based on advice you receive on an on-line forum? You are receiving some good advice, but span charts aren't that hard to find, and your lumber yard should have a pamphlet from the LVL manufacturer that can answer your question in about 5 minutes.

I don't mean to seem nasty, but it's an awful lot of liability and it all lands on you.

[Don_P.]

Re: sizing a header

This long adress is to the header tables on the CWC's Spancalc. Click on the house section that describes the situation and its chart will pop up.

http://www.cwc.ca/design/tools/calcs...t=&span_type=1

[O'BrienConstruction]

Re: sizing a header

Good link Don. I won't use that as a guide to go by but as a reference for ideas.

[Bill Lacey]

Re: sizing a header

Why wouldn't you use that as a guide? I have all of those tables in a bound book form and I use it as a guide for spans all the time.

[O'BrienConstruction]

Re: sizing a header

Maybe I'm over my head on this one, when I say guide, I mean that I won't go by it alone. I'll still check my codebook and verify with my engineer in cases I'm not sure. Is that better? I didn't read the site enough to know whether the information contained was excepted in my area. Therefore its just a reference to me. One that I appreciated and would have left at that.