Fun With Wood X-bridging

ClemS

brace yourself you may be in for some unusual techniques the architects around here are.... ummmm.. leaving a lot to be desired

i have a set of plans for a job we'll be doing beginning to mid december. the roof line is a mess. bearing walls and point loads flying wild. walls being built on brick ledges..... i've been trying to get the man on the phone all week to feel him out, he's unavailable for comment. almost looks like he died right after he drew these things. either that or he's just a jerk and screens his calls for obnoxious framers

ClemS

guess they don't consider nail pops in the sheetrock, an effect. i'm with lone 100 percent. if someone who built 100 houses tell me one thing, and someone who built none has a different opinion. tough sh*t, i'm going with whatever EXPERIENCE tells me. not a piece of paper.

loneframer

Tim, I agree that at a 12' span, there may be no improvement in floor performance. However, many of the homes I frame are designed with maxed out spans where increasing joist depth will create problems with maintaining a minimum pitch on the roof. (Yes, they push the limits with height restrictions to the point that I've had to cut studs down 4" on both floors to get a 3.5/12 in some cases.) I also know that with spans of over 14' with a Hem/Fir 2x10, drywall has little effect of preventing deflection of a single joist at midspan when a 300 pound homeowner walks across the floor. Seeing this with my own 2 eyes prompted me to start using wood bridging. I could hear the metal bridging moving under foot and saw the deflection of the joists. We are required by local inspectors to install bridging midspan on anything unsupported over 8'. I've never known any different. I joists are the exception, but they must be strapped at the least if no ceiling is attached. I've seen conventional lumber do some crazy things as it stabilizes, bridging minimizes the amount of movement that occurs if nothing else.

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loneframer

How many F-bombs did you drop during your initial message? Maybe he's seaking protective custody.

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"Walking the fine line between production and perfection"



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ClemS

i wonder if and when they test their floor assemblies they actually let a 300lb douchebag parade around the deck for several years and see if he likes the feel

ClemS

none but he sounds like a fruit on his answering machine. i like to get them before i actually start working because if they're easy about making amendments then the job goes smoother for me. i don't really like to drag them out and make idiots out of them at the jobsite because then they feel threatened and start acting like little girls. the house i did where i hung all the tji's off the steel, the architect kept insisting that you DON'T need steel structure under brick veneers that fly over a roof. he said brick doesn't weigh that much and a steel angle bolted to the house is plenty strong.... what do you think?

loneframer

Aside from wall ties and steel angles over openings, I think brick veneer should remain independant of the framing structure. A brick shelf incorporated into the foundation for bearing. What do I know though, I've only been in this game for 25 years.

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ClemS

thing that got me was, i just did a job where we had to open up a good section of the roof, remove the veneer, drop a piece of steel in and patch things up. if that's not a testimony as to how things should be done to begin with, what is? a piece of paper from someone who's having a hard time drawing the things we're building with ease?

loneframer

Just goes to show you, there is no education that compares with field experience. Calculations dictate what should work, real life scenarios dictate what actually does.

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ClemS

goes to show me i should have been an architect. i could have been screening my calls RIGHT NOW

loneframer

Both of my sons are very math minded. I'm leaning on them to pursue fields in engineering as well as architecture. They have to answer the phone when I call.

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Greg Di

Tim, is the under joist sheathing the engineer talking referring to applicable to drywall? It must be...I mean, who sheathes a ceiling, but then again, how does drywall have any strength in terms of pull through and such?

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loneframer

Another member sent me a link to this video. Thanks.

+ YouTube Video

http://www.youtube.com/watch?v=R_OF9KgWhzI

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naptown CR

Interesting video
I cannot imagine how labor intensive the last system would be unless you bought the bridging from the guy. But what about odd spacings etc.
The biggest difference is that the nails or screws are in shear and not pulling out.

I also agree with the other posts above that bridging will reduce bounce.
The jury is however out on what it adds to the ultimate strength of a floor structure.

Joe Carola

I set up a jig with a floor joists, piece of 2x6 and a piece of 5/4 and some 10d nails. I set the debth of the saw, the angle of the bridging and set the piece of 5/4 to the table of the saw nailed on top of the 2x6.

1) Take a floor joist and lay on the horse.

2) Nial a 1' piece of 2x6 flush to the bottom of the 2x10 about 2' in from the right side.

3) I sit the saw on top of the 2x6 set the angle of the bridging and set the debth of the saw so the depth touches the 2x10 and the bottom of the balde touches the bottom of the 2x6 holding the saw square and scribe the left side of the table of a sidewinder (right side blade).

4) Nail an 8" piece of bridging on that mark.

5) Butt my tape against the bottom of the 2x6 and measure to the right the length of the 5/4 bridging and tack 2- 10d nails in.

6) On the left side of the 2x10 I tack a couple 10d nails 5-1/2" up from the bottom to equal the 1' 2x6 I have nailed in for the bridging to slide across.

7) Take 16' length of 5/4x3 bridging and slide from left to right with the saw in my right hand I slide the saw up and cut the first cut. Slide the 5/4 until it hits the two nails I have tracked at the length of the bridging and sklide the saw for the second cut and the bridging is now cut to length and pops off the 2x10.

I just keep sliding the bridging until it hits the 2 10d nails and sliding the saw and just keep cutting. It goes extremely fast and not one measurement. Just keep sliding the saw and cutting.

The jig takers a couple minutes to set up. This for me is the fastest way to cut bridging. When you cut through with the saw, you just turn the saw to the right slightly and the piece of bridging pops off.

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Joe Carola

smeagol

Loneframer, you should test bridging with a 4"x6" piece of 1/2" ply sandwiched and stapled between the 1x3s perpendicular to the joists. I would guess on a 480lb breaking strength

loneframer

I agree that a floor is only as strong as the joists overall, but it is undeniable that point loading a single joist in midspan will cause deflection. I advocate that bridging forces loadsharing of the adjacent joists, nothing more.

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Joe Carola

Naptown,

Here's a drawing of the top view of the bridging jig.

Attached Thumbnails

 

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Joe Carola

loneframer

I always have a chopsaw table set up to cut wall parts. It takes about 30 seconds to set a stop block for bridging. I stand up 5 or 6 12' lengths of bridging material and gang cut them. It takes very little time to cut enough for the whole house. If I have more than one house under contract with the same builder, he will usually send out enough stock for several homes and bundle them for storage.

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neolitic

Cool Joe!

What I can't get over is....
once upon a time, in the primitive days,
I just ordered it with the lumber package.

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