[Shop-talk] Determining beam span/hanging header joists?

[Obaa]

Hi John,

The truss is an engineered truss originally made for supporting the roof on manufactured homes; I've attached a pic but don't know if it will go through.  I'm not sure what load they were originally designed for (I picked them up at a lumber liquidator), but I imagine my load (the polycarb panels) must be much lighter than anything they would have been designed for.

If I understand your header joist construction, it looks like (top view):
(inside)
      X        X   
---|------|------
------|------|---
(outside)


Where:
  X = 4x4 beam
  - = 2x6 board
  | = joint between 2x6 board.
That's more stout than what I have.  I'm thinking:

        X
--------|--------

or possibly:

--------|--------
        X
--------|--------

I'm not sure how the plywood would help with this though?


--- On Tue, 8/5/08, john niolon <jniolon at bham.rr.com> wrote:
> I would think it would be sufficient to support the roof
> load but your load 
> is something else... not the beam but  2x2 trusses ???  is
> this an 
> engineered truss or something you've come up with...  I
> covered my deck 
> 12'x24' with 2x6 roof rafters supporting metal
> sheeting (22 ga) with 1x4 
> sheet 'girts' set flush with the top of the 2x6s
> (notched in) ... and it's 
> all sitting on a double 2x6 beam on the outside
> end...overlapped about 3 
> feet and bolted in 4 places with 1/2" bolts and nailed
> about a hundred 
> times... it's supported by 4 4x4 posts (8'
> centers)... it's held a 12" snow 
> for about a week and I routinely climb on it to clean
> gutters... although I 
> limit my steps to the rafters and the bridging...
> 
> I just don't know about 2x2" material and
> can't picture a 2x2 truss in my 
> small mind...if you're still antsy about it, sandwich a
> piece of 3/8" or 
> 1/2" plywood in between the 2x8s before bolting and
> you're surely good to 
> go...  BTW a double 2x8 ?? you're gonna need some help
> to set that up there.
> 
> john
> 
> 
> > I'm planning a 10' x 22' deck cover.  I
> plan on supporting it using 6 4x4 
> > beams, spaced on both sides at the 1', 11' and
> 21' marks (10' spacing).
> > Would a 2x8 bolted to the side of the beams (or using
> those Simpson 
> > Strongtie connectors) be sufficient to hold up the
> cover without sagging, 
> > or should I plan for more support beams between the
> spans?
> > The cover itself will be made of 12 2x2 trusses (~9lbs
> each) and 11 
> > roofing panels (~6 lb each), plus blocking between
> trusses.  I'm in an 
> > area with very little snowfall, but a lot of rain. 
> I'll need to climb up 
> > there as well to install the roof panels and flashing
> (~190lbs). Should I 
> > double up the 2x8's, one on either side of the
> beams?
> > The header joist will be made of 2 11' studs.  Is
> it sufficient to simply 
> > butt them together and center the joint overlap
> equally on the center 
> > beam, or is some sort of splice needed to keep them
> together.

[demime 1.01d removed an attachment of type image/pjpeg which had a name of truss.jpg]