Need Some Help Figuring Framing Of A Roof

TurnkeyConst

Hey guys, well I have attached a couple of pictures. What I am needing help on is how to figure in attaching the 2 additions roofs together. I understand that everyone might say get an architect or engineer. I could do that but I would like to learn how to figure them myself. I am pricing a 20x35 Master bedroom and bath addition on the left of the house. Then in another picture a 25x30 Family room on the back of the house. I understand that you can tie in the roofs kinda like I have the master bedroom one drawn. Would it be feasable on the family addition? To figure these roofs how do I determine if the existing roof can support the extra weight of framing and more roofing material? Im not sure if the existing house is truss built of stick built but I can find out. I could really use you guys help on this. It would give me alot of knowledge for future projects as well. If someone needs more information than let me know I can get you most anything because the house is just 1 mile away. I did not put windows or doors in the drawing because I didnt think they were relevant. Thanks guys in advance for all your help.

Attached Thumbnails

     

SelfContract

Use the software program, they will draw details & a submitted plan for inpection also. Use AutoCAD, AutoDesk, Chieft Architecture, TurboCAD, SW, etc... and so many others. SW will also generate the material lists like how many studs, 2x4, 2x6, 2x8, etc.., what type of roofs, trusses, joints, & degree/angles to cut, to buy and/or estimate project costs, etc...

TurnkeyConst

I dont really have the money at the moment to invest in those types of programs right at the moment but I will see what I can do.

FramingFanatic

simple you already have the one directional change in the roof on the other side of the house. Do it the same way as it was done there.

wink

i think learning to design this is great, but at some point, don't you have to at least get an engineer to spec any beams or load points to get a permit?

TurnkeyConst

I understand the specs of the design loads. but I was looking to see if there was anyone out there that does it themselves. I had an inspector who used to be an engineer try to explain to me the figuring of the design loads but I didnt get this in depth with him. Now I wish I had. In the master bedroom addition I can design that in when I stick build the roof or even order stubbed trusses and frame onto them I can have them over engineered for the weight. I know my dad and them used to just build onto an existing roof with no regards to loads of course they didnt pull permits either. I know how to frame it just dont really know how to figure if I can do it or not. Do you guys just go ahead and tie a ridge beam in just like a hip roof? or what would you do if it was truss built? If it comes down to it I will have to get an engineer. They really cant explain anything to me either because the computer does the work for them along with a hefty $750 charge. Would I be better off posting these type questions in a different section of the forums? Well thanks guys

Kgmz

I don't really see much of a problem here and this is as easy as it could get.

You need to find out how the existing roof is built, trusses or stick framed.

Are you going to use trusses or stick build?

Are the ceilings flat or cathedral?

If the ceilings are flat, I would just use trusses. On the family room end you would overlay the roof tieing the existing roof to this addition. The trusses can handle this extra weight and it really isn't that much weight. For the master addition if the existing roof has trusses or is stick built with adequate members then just do another overlay there.

All I use to build most of my overlays is 2x4's for the shorter runs and 2x6's for the longer runs. And remember this overlay isn't really a lot of weight, and depending on how you build it the weight can be spread around instead of at just a few points.

A W Smith

are you changing pitches of your addtions to align the ridges? looks like you factored this with a 6 on 12 rise intersecting the 4 on 12 main roof on the far end (59 inch rise vs 60 inch) but now your facia wont align with different pitches if you have any overhang. and your near end addtion will intersect the main roof 2 feet 3 inches from the ridge in plan view if using the same pitch. I dont think the live load will change because you are just swapping roof planes but the addtional lumber for your california valley will add a dead load onto the existing 143 sq foot roof area (approx).

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Cole

Can you share the .skp file?

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TurnkeyConst

yes i dont mind send me a email to turnkeyconstruction06@gmail.com ill send it back to ya

TurnkeyConst

Yea I can figure out wether the roof is built of trusses or stick built. I really appreciate the advice. I am going to try to change the pitches so the ridges line up. We are figuring trusses on the addition on the end of the house and probrobly stick build the other addition roof so we can get the ridge there as well to line up. I think my truss guys can give me an exact peak. we were talking about it and they think that the computer will allow them to do it. So we will see from there. So if I was to have to build on top of the existing roof there wouldnt be alot of weight transfer? Is that only if I tie ridge poles together? or just because the rafter plates I put along the roof help transfer it across the roof? Well I appreciate all the advice definately helped answer my questions and anyone who wants to look at the skp file I will send it to ya via email individually. I have not been using it a real long time so you will see glitches that I had to work through. thanks again guys

Pavola

If the existing roof is raftered, add some more collar ties below the lay-on area if there's only ceiling joists. The fascias can be matched with different pitches by adjusting the heel height on the trusses or rafters. Let the truss co. know that, if that's what you want, and they can do the calculations. You'll have to give them existing OH sizes and heel heights.

Team Scream

One other concern when "joining" the roofs together is wind and seismic transfer of load from one structure to the other.
In California you may be required to get an engineer involved no matter what as all of the spaces you mentioned are living spaces.
Live load is one thing but you have those other 2 elements to consider as well.
<edit>Ooops.....somehow I was under the impression you were in California.....maybe the seismic element is not as much of a concern out there?

wallmaxx

Pix here

Pitches? Gables? Ridge type?

If you can get into the existing roof...install a purlin across all of the rafters that will have the new lay on valleys on them. Brace it down to walls....not stiff back.

At the point where the new ridge crosses over the existing wall, install two braces. One directly under the ridge at the wall (vertically), and one at about a 14:12 pitch from the same wall towards the existing roof to up under the new ridge. That should help transfer some of the roof load to a wall.

Hope this helps.

Good luck

Mike

A W Smith

looked at your pix. I think he said he will be aligning ridges so now his ridges will intersect with the main roof and the roof pitches will be different. Also heel heights for his facia will be aligned.

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kevjob

Here in Denver the first question out of the building dept will be " How did you calculate and figure the loads" etc... Second question will be "when can you come back with an engineers stamped plan"

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wallmaxx

Whoops...serves me right...maybe I should read ALL the posts.

I'll fix that asap

Ya know.....I am really becoming an old fart....the name Relic comes to mind (CDN TV show 25 years ago) Here it is a perfectly good Friday night, and I am nerdin out on the computer.

wallmaxx

I am assuming 24" OH....You can substitute material one size down if your codes allow, but then with 2x6 rafters, you almost always have to install purlin bracing.

Mike

zzzzzzzzzzzzz

TurnkeyConst

Hey guys well thanks for your drawings. definately helping out. seismic loads do not apply here in north carolina basically just live and dead loads and wind loads if oh gets more than 2' Im not sure what programs you guys use to do your layouts but they look good and very informative. I understand about the braces used to help stiffen the extension ridge from the addition. Thanks for you guys help on this project.

A W Smith

might want to put a 5 or 6 foot section of 2 foot soffit where that 5 x 5 notch is and return it against the wall. Also the pix in the OP appear to have a one foot rake overhang (i call them fly rafters others barge boards)

Wallmax what software are you drawing with? Im lovin it

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