My offical build thread for a 20' x 24' 1.5 story

[willie1280]

So i figured since i'm officially starting the design of our cabin that i should start a thread to track my progress, get answers to questions and field suggestions from seasoned builders.

The plan:
Modify John's 20' x 30' 1.5 story plans to fit our 20' x 24' desired size.  Since we cannot afford to do the entire project right away, i am doing this in stages.  The initial stage is to get the foundation done, get the shell up and use it as a garage until we can financially afford to finish off the interior.

So here are the first pictures of what I have drawn up thus far:

[Don_P]

You have a weak hinge in the gable walls. Either balloon frame them to the roof or platform frame them from floor to floor. Think of the sheathed floor as a deep horizontal beam. If the joint in the wall occurs there and the wall is hit by wind, no flex. Raise it up to where you have it drawn, potential flex.

The rafter ties need to be in the lower third or you need a ridge beam, read the codebook on roof design, you'll get a strong safe one using their methods.

[willie1280]

As for the weak hinge in the gable walls I think your referring to the lack of studs on the end gables right?  If so, that was going to be my next question . Seems like balloon framing would be more difficult. Platform framing would just essentially be building another wall directly on the one I currently have correct?

As for the rafter tie, I just drew it exactly as johns plans have it. He has no mention of a ridge beam in there.

[willie1280]

Maybe I misread. So if I platform frame are you saying I should lower the gamble end walls down so the sill is flush with the top of the floor joist?  If so, how do I tie the 4 walls together? I thought I was supposed to lap the corners with the top sill plate.

[Don_P]

As for the weak hinge in the gable walls I think your referring to the lack of studs on the end gables right?  If so, that was going to be my next question . Seems like balloon framing would be more difficult. Platform framing would just essentially be building another wall directly on the one I currently have correct?

Platform framing would be to lower the gable wall top plate to floor level, tie the wall to the floor there and then build a wall from that rigid diaphragm up to the roof diaphragm, you've got a joint in between those points now.

Yes it would be ideal to lap the corners, if you'd like to do that remove the kneewall. You can wrap a metal strap around the framed corner to reinforce it .

As for the rafter tie, I just drew it exactly as johns plans have it. He has no mention of a ridge beam in there.

You asked for comments from seasoned builders, the correct way to frame is to use the approved methods in the codebook or to use an engineer. That is not an approved method, I'd switch to one that is, that's where both my comments were coming from.

[willie1280]

Don, what am I gaining by moving the gable walls down vs. doing like this http://countryplans.com/smf/index.php?topic=6311.20

??

I need the knee walls so that I can get 2 bedrooms upstairs that I can stand up in (I'm 6'5-6'6 tall).

[Don_P]

willie. I assume you've found a photo of what you've drawn. If you look around you'll find sketches and photos of any and everything. To maintain tact I'm not commenting on others work, I'm commenting on the original drawing.  Do take the time to read the codebook, whether you have to comply or not most of the stuff in there is there for a reason. I've pointed out the weak hinge this puts across the wall. As well, all of those areas that balloon through the second floor system also need fireblocking, every bay all the way around the building isolating one floor from the other.  That's one of the reasons balloon framing was largely abandoned, fast fires in unblocked frames.

You can hold the corner together with a metal strap wrapped around it better than the lapped plates so I'm not seeing that connection as the greatest concern. If you use short kneewalls the ties as shown are too high on the rafters. The typical solutions are trusses or a ridgebeam. For a third alternative, most of these houses if the kneewall is about 5' tall then the tie drops into the correct lower third of roof height.

[willie1280]

Well i added window and door openings including the garage door on the front side.  I also added the fireblocking on the sides....still need to do the front and back.