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StructuralEng
StructuralEng, Consultant
Category: Structural Engineering
Satisfied Customers: 6747
Experience:  Structural Engineer
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Background: In my 1954 California home, I am seeking to install

Customer Question

Background:
In my 1954 California home, I am seeking to install a new 36" doorway from my kitchen to my (attached) garage where the floor is 3ft lower than my kitchen floor. The new doorway is planned further back in the garage to give more space in the front of the garage. It is to be installed adjacent to the existing doorway, separated by a single reinforced garage ceiling joist. The ceiling joists in the garage are 2"X6" on 16" centers spanning 20ft from the the kitchen wall to the opposite wall. Those ceiling joists meet the kitchen at 70" from the kitchen floor blocking the doorway. It is understood, two joists need to be cut to make head room in the new doorway, and the adjacent joists need to paired up with an extra beam.
Here's the problem:
The original builder did not pair up the joists around the existing doorway. There should have been paired joist, already existing at the location between the existing doorway and the new planned doorway, but there is not. The question is how to reinforce the joist between the existing doorway and the new planned doorway.
A few alternatives are considered:
1) "pair" three "2X6" together to make a 3-beam joist (not sure if hangers are available for three s"2X6" side-by-side "2X6"s). The 3-beam joist would span the 20ft from the load bearing kitchen wall to the opposite load bearing wall.
2) pair a 2"X8" with the existing "2X6". Span as in 1).
3) pair a 2"X10" with the existing 2"X6". Span as in 1).
Submitted: 9 months ago.
Category: Structural Engineering
Expert:  StructuralEng replied 9 months ago.
Can you post a sketch? The text is not very clear.
Customer: replied 9 months ago.
It is difficult to post a sketch, perhaps you can state your questions. This description may help. Please picture ceiling joists in the garage attached to wall separating the kitchen and garage. This is split level with the garage floor 30" lower than the kitchen floor. These garage ceiling joists span 20ft except where there is a doorway between the garage and kitchen. In the doorway the joists are cut back allowing space for the doorway (because joists are at 70" height relative to the kitchen floor). The question is: how to reinforce the garage ceiling joist which meets the kitchen wall between the existing doorway and new planned doorway?.
Expert:  StructuralEng replied 9 months ago.
What exactly is the span of the beam you want to build?What is the joist length on each side of the beam?Is it supporting attic space only?
Customer: replied 9 months ago.
(Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Customer: replied 9 months ago.
1)The exact beam length is 235" (19ft 7in) assuming it is hung on the face of the walls. If the beam is supported by studs inside the wall, then it would be 8" longer, 243".(20ft 3in.)
2) The joist length is the generally same as the beam length except in the doorways where they are cut back. The two joists cut back for the existing doorway are 151" , in other words 92" shorter than the length of the others. For the new doorway, my plan is to cut back the garage joists by 4ft.
3) Yes, the joists are supporting attic space only.
Expert:  StructuralEng replied 9 months ago.
Are the joists perpendicular to the beam?
Customer: replied 9 months ago.
No, the joists and the beam run in the same direction. My thinking (tell me if it is correct) is that "the beam" is really a reinforced joist spanning 19ft 7in.
Expert:  StructuralEng replied 9 months ago.
Ok. So you have a short header because some of the joists are shorter. Then that short header spans to the joists that run full length? How long is the header?How far is the header from the end of the adjacent full length joists?
Customer: replied 9 months ago.
1) Yes there is the header you describe.
2) The header is 4ft long (spanning between 20ft joists on either side of the existing doorway).
3) The existing header is 92in from the header to the end of the adjacent full length joists. For the new doorway a new header is planned to be 48in from the end of the full length joists.
Expert:  StructuralEng replied 9 months ago.
And these are 2x6s spanning 20'?Is there attic space above these joists?
Customer: replied 9 months ago.
1) Yes these are 2X6s spanning 20'.
2) Yes there is about 4ft of attic space at the crest of the roof.
Expert:  StructuralEng replied 9 months ago.
The joists are significantly undersized for that span as-is. I would sister each with a 2x10 that matches the bottom of the existing joists.
Customer: replied 9 months ago.
Ok, but just to confirm, are you suggesting there be only a single 2x10 sistered to the single 2x6 between the existing doorway and the planned new doorway? Keeping in mind there are 2 joists on either side which are cut back. I would like to tell the inspector whatever I modify would meet 2013 Calif bldg code.
Expert:  StructuralEng replied 9 months ago.
The joists that support the header should have 2x10s sistered to them
Customer: replied 9 months ago.
Also what type of hanger is recommended for the sistered 2x6 + 2X10 joist. I suppose a 2X10 hanger, but can you be more specific. Are you recommending sistered joists to be nailed, screwed or bolted together? Does it matter?
Expert:  StructuralEng replied 9 months ago.
nailed. It should bear on the same wall that the 2x6 bears on.
Customer: replied 9 months ago.
Hanger specification? (for the joist hangers bearing on the same wall that the 2x6 bears on adjacent to the new planned doorway will supporting a single 2X10 sistered with a 2X6.
Expert:  StructuralEng replied 9 months ago.
What? I didn't follow any of that.
Customer: replied 9 months ago.
Sorry, accidentally sent that before correcting grammar.
Hanger specification? attaching a single 2X10 sistered with a 2X6 ( bearing on the same wall that the 2x6 bears on) between the new planned doorway AND existing doorway. The thinking is to mount the hangers for 2X10+2X6 sistered joists on studs.
Expert:  StructuralEng replied 9 months ago.
You can't mount it to the face of the studs. You would need a ledger.
Customer: replied 9 months ago.
OK, there needs to be a ledger. What is the minimum size of the ledger. That will determine the minimum distance between the existing doorway and the new doorway. I've heard hanger names "UH" and "UL", does that make a difference in minimum ledger size?
Customer: replied 9 months ago.
I would like to place the new doorway as close as practical to the existing doorway. I am contemplating there would be 2 or 3 new studs inserted side by side.with the existing two door post studs. The existing studs plus the new studs would support a 2X6, 2X8, or 2X10 ledger. The ledger should be what minimum length, and how many nails or screws should be used to fasten it to the studs.
Expert:  StructuralEng replied 9 months ago.
This is detail stuff. I can provide all of this as an additional service, if you want.
Customer: replied 9 months ago.
You have been doing great so far. I am not sure why you are holding back on this detail.
Customer: replied 9 months ago.
However, the general question remains, what is the minimum size of the ledger?
Expert:  StructuralEng replied 9 months ago.
Because the question was about a beam size. This is very detailed information that requires a significantly more amount of effort.
Customer: replied 9 months ago.
I understand, please allow me to rephrase the question to make it easier to answer. What is the size of the ledger, including significant margin of safety, for a simple calculation (without significantly more amount of effort)?
Expert:  StructuralEng replied 9 months ago.
Double 2x8 if attached to every stud.
Customer: replied 9 months ago.
Thanks. Please let me know if I understand you correctly. I'm picturing four studs side-by-side forming the shared door post between the existing doorway and the new planned doorway. Two 2X8s will form a ledger fastened to each of the doorpost studs. The grain of the 2X8s will run horizontally. The approximate dimensions of the ledger are 1.5in X 7in X 15in (a pair of 2X8s cut to span four 2X4 studs).
Customer: replied 9 months ago.
.. and the joist hanger would (clearly) be mounted across both 2x8s.
Customer: replied 9 months ago.
Instead of double 2X8, could a single 2X10 or 2X12 be used for the ledger (attached to every stud)?
Customer: replied 9 months ago.
Trying to verify what you meant by double 2X8...
Customer: replied 9 months ago.
You've been doing a great job. To complete this session, it is simply necessary to answer the above simple questions.
Expert:  StructuralEng replied 9 months ago.
Two 2x8
Customer: replied 9 months ago.
Can you confirm what is meant by "double 2X8",It sounds like a pair of 2X8s mounted adjacently on the studs--with the grain running horizontally (mill finished 2" side of upper 2X8 adjacent mill finished 2" side of the lower 2x8. If my understanding is correct, it sounds like a 2X10 or 2X12 could also be used instead of two 2X8s.
Expert:  StructuralEng replied 9 months ago.
Correct on both accounts
Expert:  StructuralEng replied 9 months ago.
Hello. Do you have any other questions for me on this topic? If you could rate my answer, I would appreciate it.

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