Second Story Addition Floor Framing

[fitz]

I do mostly additions.
The way we put the second story on is to:
Retain the existing CJ of the first floor,
Single or double flat plate on top of the CJ above the exterior plate,
Install TJI above that.
What is the best way to do it so the framing shows properly in section?

Mike Hall
San Diego

[M.A. Winterton]

If you aren't worried about material lists and just want the section drawing to look correct, the easiest and quickest would be to set your first floor joists, to a depth for the total ceiling joists & floor Joists to get correct floor levels. Then in cad use a cross box for seperating plate, with 2 white filled polylines (or filled stretched boxs) to represent ceiling& floor joists. If joists run other way use muliple copy tool with cross box for joist and to lines.

If existing plate is good enough, we tend to run our new upper floor joists beside existing ceiling joists locally, then if a hanging beam is removed that breaks existing joist span, you bolt or nail existing to new joist beside to support ceiling. Gives you less upper floor depth & less stairs are needed.

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[fitz]

Hi M.A.W.
Thanks, sounds like you are familiar with the process, and have explored any other possibilities.

I have questions/comment about runnning floor joists alonside existing joists.
1. Limitations would be the existing joist direction.
2. Relocation of wiring, gas & water lines in the existing attic where we are building. Do you just rewire/replumb everything?
3. It would work especially well where trusses are being cut, leaving just a 2 x 4 bottom chord, a present situation.
Thanks again

Mike Hall
San Diego

[Chieftain]

This double framing maneuver can be done with the existing framming tools in Chief, but you will have to draw both the CJ and TJI's yourlsef. Go ahead and draw one or two of each and open up their specs. You can here change the top hight and size of each one. Then you just have to draw away with the manual tools copying each. I think you can put them on different layers to so that you can change their color/line type as a group, and lock them so you can work on one without destroying the other.

[Chieftain]

Oh ya, This top hight adjustment also makes it easy to specify girders under floor systems and such similar situations where framing for the same "platform" must be at different levels.

[M.A. Winterton]

Fitz you still have to do alot your way, if theres to much infrastructure above, I was just giving you another alternative. As you said works great with modern houses when cutting out trusses and supports existing ceiling. Most older style homes around here on small blocks central to town where people extend up for lack of room, have timber framed floors with pipes below just wiring in ceiling which generally need upgrading and they all have the same basic layout 12'x12' rooms either side passage down the middle (a hang over from U shape roof with box gutter in the middle to catch more rain fall) so normally the joist run across same as rafters but if not your method. The additional hieght can be a bonus sometimes if clients are after high pitch roofs with dormers and including eaves.

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[fitz]

MAW & Chieftain
I did it but it took hours!! And this was a simple "L".
I did it in 3D. Maybe MAW's is the better way because now my exterior stucco is not continous between floors.
TJI's took a lot of time, putting those three pieces together.
Using a different layer/color for each piece
and added top plate above joists is the way to go.
Those 3D framing views really do take you breath away - awesome!
Would love to see TJI as a unit, I am going to be using them almost every time.
Any one want an email of it to view or offer suggestions?

Mike Hall
San Diego

[fitz]

Stucjoists apparently are our TJI
Mike

[Chieftain]

Mike,

I for one would like to see some pictures or your plan!

I hadn't even thought of pieceing together a TJI that way. I'll have to try that. I use them quite often myslef, but have always just used a standard joist to depict them.

Caleb
Caleb@3dbuildcenter.com

[M.A. Winterton]

Fitz, What exactly is a TJI I thought you were referring to a timber joist.
Over here theres a range of other products.
1 Steel channels or I beams
2 Strucjoists which are a timber top & bottom cord with solid ply web (cut holes for pipes)
3 Posistruts same with steel webbing
4 Timber or steel trusses
5 Laminated timber beams
There are other types and versions of engineered products to and all the names change with the manufactures of course.

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