I have a question on a beam connection.
I am renovating our kitchen, taking out a load-bearing wall ( I have a permit already J ).
B1 (new beam to be installed flush with existing joists) is 3 -2×8 spanning 10’-6″, to support a 2nd floor. Joists (span 10’-6) , 2×8 @ 16″oc will be attached to one side of beam on joist hangers. Joists on other side of beam are parallel to beam.
B2 (existing) 4- 2×8 flush with existing joists.
B1, at one end, will sit on 2×6 wall with 4-2×6 post built-in. Other end will be connected to B2 at a right angle and is directly over a free standing post of 4 – 2×6.
My problem is the connection of B1 to B2. I do not think a joist hanger for 3 2×8’s with 2″ bearing will be strong enough for this connection.
Any help would be appreciated.
Replies
Seems to me like B1 ought to be LVL, and depending on the loads above, two 2x8's should do it. Less weight, less deflection.
If a joist hanger is rated for three 2x8's, it's designed to carry the load. Just be sure to use full 16d spikes -- not the little Simpson nails -- to make the connections. Those little nails are only for single pieces of lumber.
If you're still worried, bolt the connection together with a pair of angles. That's overkill, but you'll never wonder about it again.
My larger question here is, did a structural engineer spec your beams and connections? Around here, the inspections department would require an engineer's stamp. I usually get an engineering consult if there's any doubt whatsoever.
I didn't check with an Eng., Ontario Building Code has tables for built-up wood beams. Min. sizes are 3 - 2x8, for SPF No. 1 & No. 2, span 10'- 8" supporting length (joists) 7'-10". I don't think 2 - 2x8 would work. If this did not fall within the tables I would have gone to an Eng.
I first thought of using the triple joist hanger, but I checked the tables on their web site. Simpson Strong Tie LUS28-3 is rated for 1050 lbs. allowable load for Floor loading, using 6-16d into header and 4-16d into Joist.
From my calcs. at this connection, I have 6'-1" (half joist span) x 5'-3" (half beam span) = 31.92 sq.ft. of floor load.
31.92 x 50 psf (40 LL + 10 DL) = 1596 lbs. which is too much for the LUS28-3.
Only other sizes are triple 2x10 hangers which are too tall for 2x8.
"If a joist hanger is rated for three 2x8's, it's designed to carry the load."
No it isn't. That just means it's the correct SIZE. It has little to do with how much it will carry.
Science is not wisdom, it is knowledge.
Wisdom is knowledge tempered with judgement.
Try Simpson LUS28-3 or U26-3. They're advertised in the catalog for triple 2x8. Probably not a stock item at HD.
I'm sorry, I thought you wanted it done the right way.
Ed, I actually did buy the LUS28-3 at my local Lumber yard. When I brought it home, I started to doubt my thinking and looked at the Simpson load tables..... see my post above for what I think are the results.
Edited 5/10/2005 11:11 am ET by scottbr
Do you have a truss plant nearby? They should have something like a Simpson HGUS28-3. They're designed to support girder trusses, and are good for several thousand pounds. We typically give hangers away in these situations.If there aren't any truss plants, your lumberyard should be able to special order one for ya.
We all get older too fast, and smarter too slow.
Hey Boss, thanks. I had downloaded the Simpson catalogue and was looking through the face mount joist hangers and had not seen that one in the truss hangers. It's a bot of overkill, but it is the right size for height ( I was looking at the 2x10 size which were too big) and has the min. bearing I need, 3 1/2".
I thought I was on the right track but just needed the nudge in the right direction. I have both a truss manufacturer and building supply place close by that special order if they don't have one.
Thanks again.
Scott