Help with roof framing options

[aspireonescs]

Hi all, new to the boards (been a guest/lurker for awhile though) and have just been brought in to help a family friends father (owner/builder) with finishing up his house. He already has alot of it done, however there is one grey area in the following picture. My first day here I went and measured everything then made a skecthup model of it, to try and figure out the roof framing on the one part where it is missing. any advice would be greatly appreciated. everything in the pic/ model is as it is in real life.

you can email me at scsimmon@gmail.com if you would like the sketchup file. thanks

[aspireonescs]

Here is the .skp file: http://www.megafileupload.com/en/file/539898/final-framing-skp.html

[Don_P]

I see several grey areas . Is that to be a shed roof extending down from the roof sheathed in grey?

If you can save and upload it in skp version 8 i'll be able to open it, should be able to do that in your save options. Sorry I can't get newer than that on my computer.

[aspireonescs]

Ya I am not completely finished with the model compared to what he already has built, but it is mainly just doors/windows/stairs and the osb on the trusses that is missing. His original plan was a shed roof however he/we are not sure that is the best way to maintain a good pitch/room for insulation. the other roof with the trusses is a 3/12 i believe. (not much snow here in so IL) Here is the link to the version 8 save: http://www.megafileupload.com/en/file/539974/final-framingv8-skp.html, I am using the newest version, and forgot that others may not be  . They have been working on it for a year now and finally called out for help, It has just been an 80 year old man (he can almost keep up with my 28 year old self  ) and his daughter and a neighbor here and there.

I appreciate you taking a look at it Don, I'm stumped and he is as well. the area yet to be roofed was added as an afterthought, as the main stairwell was taking up too much room from that bedroom. So they put that addition there "on the fly".

[Don_P]

something is catywhumpus in your model, I didn't go looking for it just sketched in quickly for the idea. The pitch on the old roof is ~1-5/16 /12 and it is creating a water issue at the skyroom wall. throw that roof into the yard and ledger on the sidewall of the skyroom and run at least a 3/12 roof off of it. I just let the right side roof come back down at whatever to land on the wall drawn, there could be some things to do to make that more symmetrical and pleasing to the eye. anyway a thought.

[hpinson]

Aesthetically, my eye seems to want the sky room roof to be at a similar pitch to the lower roofs.

[aspireonescs]

Thanks Don, I will check that out, and I agree  hpinson, however the owners like it that way. (and in person it does not look that bad) That skyroom was another "might as well" afterthought addition apparently lol. I have got to get to the dentist in the next couple days to get this painful rotten wisdom tooth out before i get up on the roof again with my messed up balance.

[Don_P]

I put the same rafter on the right side as the left to show what symmetry would look like.
remember that below 3/12 roofing options narrow quickly and tend to get more expensive and less reliable... just part of "selling" the removal and replacement of the original roof, which will be an expensive thing to maintain over the life of the structure.

On the tooth, go get some activia yogurt and eat that stuff till you moo. They are going to put you on heavy duty antibiotics that'll kill your gut bacteria and can allow c.diff to grow. That can be miserable or worse. avoid clindomycin (sp?) if at all possible. Take care of yourself, construction body stress and that infection are a tougher recipe than it seems right now

[aspireonescs]

Finally got my tooth out, man I feel much better now! Will get back to the fixing of the friends roof this week. However on a side note, they want me to design a master bedroom on the second story. Basically they want 6x6 upright support posts 8' off the ground. (no framing or rooms underneath it. i.e open space below) And the size they want 12'x18'. I am thinking 12" (11-7/8) I joists for the 12', using the  i joist hangers. However I am not sure what the beam size would be to run 18' without any walls/ support underneath, save for the 6x6's on the four corners. Best I can figure is 3-2x12's or an engineered beam. Would the 3-2x12 work? and if not what size/ kind of engineered beam would I need? A LVL, but how many ply? this is with the 3ply 2x12:


Edit: after a quick Google search, it seems that if I add another 6x6 in the middle of the 18' length, I can use 2-2x10's /2-2x12's? like this: any suggestions? A little rusty on beam spans here lol

[Don_P]

Glad the tooth is better.
Shorter beam spans certainly help. You'll need more info to size the beam though. I assume there is a roof being supported by the beam as well as a floor. Sketch the proposed room into the model and highlight it in a different color or put it in another layer and post the file. Also need to know your design snow load, the local building dept can supply that.

[aspireonescs]

Will do in the morning, as to the building dept. No building code here, only Il state epa septic codes. Yes there will be 8' walls and a 3/12 pitch roof (trusses) in addition to the floor. Ground snow load in this area is 15psf, I believe the closest town with a building code (23 miles away) has a design snow load of 25psf. We literally have like 3 people that run our town, the "mayor", the tiny little water dept guy and the gofer guy. and just a little tiny office/town hall/"fire dept"/water dept building lol

[aspireonescs]

Don_P here is the requested model (in skp version . Sorry it is not perfect, its a little busy around here and noisy (kids). Not to mention the power company is doing something down the street and I had to start over 4 times today. http://www.megafileupload.com/en/file/545299/masterbedroomV8-skp.html

[aspireonescs]

Here is a few real life pictures of what I am working with, the first is where the proposed master bedroom is going. The second and third shows how we did the roof after my first post, it was a compromise from what Don_P and others suggested, and what the owner wanted/funds would allow. I know it is not totally aesthetically pleasing but that's what they wanted and are happy with it. The fourth shows the stairs to the skyroom, and the fith shows the view of the Ohio river and bridge from the skyroom.

[Don_P]

Quick comments;
I couldn't see the last 2 photos  You're near Cairo? Just as an aside I'm on the east side of the Continental Divide in the Blue Ridge in VA, my little creek is in the New river watershed, drains to the Kanawa, then into the Ohio.

The roof repair is not a great one, that ridgebeam was already undersized/ overspanned in the model.

That is 15psf snow on the ICC map but in the New Madrid fault zone bigtime, Seismic E. Brace well ( and you should be throwing up some sheathing quick, she looks tender to the wind now.. I signed up for a seismic/wind/snow class at Tech for Sept... which does you a heck of alot of good now  The 25 live load + 10psf dead load would not be a bad idea. Then 30psf live + 10psf DL for a sleeping room floor

On the addition, the valley/hip is not self supporting, there needs to be a post under the ridge/hip/valley intersection... it could land on a beam at ceiling height if carrying one through the floor to the ground is objectionable, but that load needs to be traced and supported. Is there a level ceiling (tied) or is it going to be cathedral ceilinged (some type of ridgebeam)?

[Don_P]

playing a little,
a double 2x12 works as a 14' ridgebeam for the main span
A triple 2x12 works as a beam on the walltops under the intersection of ridge/hips/valleys with a short post up to support that intersection.

[aspireonescs]

  Not sure about the pics, they show up on all my devices, Ill try editing the post and reinserting them. I'm in old shawneetown, right where IN, KY and IL meet  . I know it about the roof repair, however they wont listen to me or budge on it. It however did stand up to a bad winter with a lot of snow last year though apparently  In the model I did not represent it correctly it has 2*4's running on the bottom sides and 2*4's running at the top, under the rafters. Sheathing is the next item on the buy list, but they can not get it till payday, on the 4th , along with the 2x6's for the missing wall downstairs.Bridging and diagonal braces are planned, however my Paslode impulse framer bit the dust and I just got it fixed this morning. A post up from the ground would not be too bad, it could go at the corner of the bath and closet in the addition  (which is about right where that intersection occurs) Not too sure about the ceiling, the intended tenant is at work at the moment. however I do believe she wants a flat ceiling. I did not do that in the model as I was up to my ears in first graders (the owners daughter had friends over) I just could not focus, and the power was blinking on and off, I still don't know what the power company was doing, there was not any downed lines  I'm uploading a picture of the floor plan that they did in smartdraw so you can see where the post could come through the floor. (the addition is on the far right)

A double 2/12 sounds about right, I need to get my hands on some beam span tables, however my google-fu is seriously lacking lately lol. I do have a floor joist span table from awc.org though.

[UK4X4]

If you sort of know what your doing.....this is free and worked for me, even supplying the outputs with my dwgs to the building inspectors.

http://www.woodbywy.com/software/forte-software/

"however they wont listen to me or budge on it"

sounds like a signed disclaimer required to prevent later comeback

[aspireonescs]

Thanks, ill check it out. No disclaimer needed, I'm not getting paid, and me and the owners daughter are sweet on each other  . I will think about a disclainer from her dad though
(on the down low  )

[Don_P]

Ah, east side of the bottom of the state.
If there is a flat ceiling and if you can lose the hip, the framing and bearings can be a good bit simpler.


The flat ceiling ties the rafters, so a ridgeboard rather than a ridgebeam works. The valleys can then be overlaid on top of that simple gable roof, sleeper on top of that main bedroom roof sheathing a pair of valleys that plane in with the existing 3/12 trusses on the main building and frame jacks to the intersecting ridge and valley sleepers... a "california valley". No support post under intersecting hip and valley framing, and there are no hips as precedence elsewhere on the house

[aspireonescs]

Ah that's perfect  , exactly what I was looking for. I just get caught up in all the other things, that the simplest things escape me   . Thanks a billion Don_P, you have been a great help so far and I deeply appreciate it. I am still plugging away at the owners to allow me to fix the roof the right way. The way it seems, is that if this was tax time they would let me do it. So maybe next year ill be up there tearing it off and doing it the right way  .

[Don_P]

OK, now we have enough to figure loads on the girders.
The room is 12x18 there are 3 supports along each 18' side making the girder spans ~9'.
The roof bears half its' weight on each 18' wall. So for a 9' girder length the girder is supporting 6' of roof width + ~2' of overhang, about 72 square feet. We decided the design roof load is 35 psf... 72 sf X 35 lbs/sf = 2520 lbs

The tributary area of floor to that girder would be 6' (half the room width) X 9' (girder span) X 40 psf = 2160 lbs

Total uniformly distributed load on the girder is 4680 lbs.

http://www.timbertoolbox.com/Calcs/beamcalc.htm
Load is 4680
Span 108" (its' actually a little less)
Width 3" (try a double 2x12)
Depth 11.25
Fb 1000
E 1.4
Fv 135

A double 2x12 in #2 SPF lumber would work.

Personally, I'd use 2x8's (min) or 2x10's ( a bit less bouncy) for the floor joists rather than TJI's in this location, exposed and likely to have combustables under there... takes longer to burn through lumber than TJI's in the event of a fire.

[aspireonescs]

Thanks Don, that math has always confused me, but the way you wrote it it suddenly clicked in my mind  A double 2x12 is what I was leaning for in the first place. As far as the TJI's, I was at Menards last night and boy they are like 22 bucks a peice. 12' 2x12's were 16 something, so ya we will go with the 2x10's or 12's and not 2x8's That roof you drew is perfect. I have to help a guy build a chicken coop and put up posts and fencing and netting today, so when I get back I'll work on the model. Quick guess its 2x4 rafters and a 2x6 ridge?

[Don_P]

Thanks, I try to walk through stuff when I can to help things "click", same thing as showing someone how to fish rather than just giving them one fish  .
2x4's work spanwise for the rafters but if there is an overhang they fail to be able to allow the minimum 1-1/2" level seatcut bearing on the wall while still providing a minimum of 3-1/2" above the notch. So really it takes a 2x6 rafter and 2x8 ridgeboard. The ceiling joists are also 2x6 for the 12' span unless you go to 2x4's in Select Structural grade (which will be more $ than the #2 grade 2x6's).