Citydude
Elite Member
Use liberal amounts construction glue to laminate them along with heavy gauge screws.
Simple Framing Question
- Thread starter Diggin It
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Use liberal amounts construction glue to laminate them along with heavy gauge screws.
jthibodeau89
Gold Member
3 layer 1x8 or 1x10 laminate beam may be cheapest way. Can also use 1x6 & 1×4 to get 10" width. Stagger all joints. Lots of PU glue. Tack together with #9 # 1 3/4" on first side, flip beam, #10 x 2 3/4" all the way through. This gives me an idea to replace the rafter beams on my shed.
I suggested steel joists because we have a terrible carpenter bee issue in our 20x50 shed. Had to wrap girts with flashing and replace wood king trusses with site built cfs steel trusses. Shed originally built in '98 or so (not sure as we purchased property from an estate).
Pics please when done.
the viking
Bronze Member
Why don't knee braces reduce the span? I always thought they did as well as providing lateral support. Deflection in the post is possible if it is undersized or if there is not 2 opposing braces?
/pine
Super Star Member
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Do a little research on "basic structural loads and resistances" etc...
The "span" is between "bearing points"...Those angle brackets do absolutely nothing to reduce the span...
FWIW...for typical 45* angle braces to be truly effective they need to be through bolted to both the post and the beam...it does not take much lateral force to rip out tails or screws that applied from the face of the cuts...
ArlyA
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Those angle brackets do absolutely nothing to reduce the span but are important for side loads, like wind.
/pine
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That depends on the spacing of the rafters etc and what is being applied on top...i.e., solid sheathing on say 2'OC rafters that are secured properly to the beam will eliminate the need for lateral bracing on the posts...same goes for lattice boards and metal roofing...for the most part they (post braces) are there for the looks...once the roof is on they do very little to add lateral support...and like I said in a previous post...through bolting is paramount for them to be effective...!
the viking
Bronze Member
You speak like an engineer, are you? People who use screws have a few loose ones unless they are listed for lateral loading. Screw one half way in and one sideways hit with a hammer and most will snap off. Lag bolting or thru bolting knee braces is the norm. In the real common sense world I feel that properly designed and installed knee bracing can support gravity loading and create an additional bearing point. Any structural guys here?
MF RED in MT
Veteran Member
If you sandwich a full length piece of galvanized sheet metal, 24 or 26 gauge, inside of your 1"x8"s, and fasten your "sandwich", you will add a lot more shear strength.
Years ago this was a common practice when adding an additional roof joist to an existing one for an add on a/c unit on the roof, 4/12 pitch, to support the additional weight of the unit and help out where the roof was cutout for duct work.
We use to also turn a 90 degree flange of about 1.5" for the bottom side of the metal.
Good luck, KC
jthibodeau89
Gold Member
Like in a truss, the diagonal members are more for tension. The racking loads are tension on one side, compression on the other. If angle of support is 45 or less from vertical, properly anchored to post, sized for compression, and meet near center of span, then it can be considered to reduce span. Think post and beam construction. But such a structure will severely limit access. Better to just use a proper header beam sized for the span. The are other ways to support a span, such as a tension member on the underside with a center drop leg, or a fabricated pre-arched beam. But these are probably over designed for the OP's needs.
You can consider galvanized CFS for the span beam. I have built 6x12, 3x10, and 6x10 box beams from CFS studs and track. As well as the Howe truss pictured previously.
I am an engineer.....
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/pine
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I'm not a structural engineer...I finished with a double major (civil engineering and architecture)...held a class A GC lic. in FL for 45 years...
IMO this is all moot...if the OP uses mostly clear oak members followings following basic soft wood framing practices...(for sizing members)...the oak beam is not going to deflect without an extreme live load...
