First cabin project

[appster99]

Hello forum folks!  I am about to start a new cabin project in which I am retrofitting an existing 22'x22' two car garage with a timber frame loft and adding a 10' lean-to for laundry, bath, and closet space.  I have attached a draft made in SketchUp of my thoughts so far. 

A little bit of info; there is a course and a half of 8' block around the perimeter of the slab except for where the garage doors are and a back door; there is an 8' 2x4 framed wall which I will have to fir out to meet insulation code; the current roof system is 5/12 pitch and will be replaced with 12/12 to make room for the loft area. 

The back door will lead into the addition.  I will also add a lean-to on the front side for a porch, but that isn't drawn on yet.  It will mirror the back roof system exactly but be open.  My questions are:

1. I have a guy who I can get Yellow Pine, Oak, or Poplar from for very cheap.  I can get it sawed any size up to 16' long.  I'm planning on 8"x8" right now as that is what is drawn.  Which species will be most stable and best to work with?

2. I have drawn the perimeter beams all less than 8' long since they must be man-handled inside the building with the joint sitting top a post for strength.  They are currently drawn as lap joints, but I'm open to suggestions for better joints.

3. How can I efficiently adjust the frame where the cross beam that supports the loft and stairs ties into the perimeter beams on the side opposite the stairs?  The inset area making head-room for the stairs terminates that end away from a post making mortise and tenon a good choice (I think), but the other side is a little more difficult.  Suggestions?

I think this is a good start. I look forward to comments and feedback.  By the way, I have a lot of dimensional lumber framing experience, but this is my first timber framing project.  I've built furniture and done mortise and tenon joints there, but nothing of this scale.  Thanks in advance for the input.

Brian

[witterbound]

If you're goin to take off the roof to change the pitch, why not add some knee walls to add more usable space in the loft.  Your post point loads might need to have additional footings, if a building inspector cares.

[Jay C. White Cloud]

Hi Brian,

1. I have a guy who I can get Yellow Pine, Oak, or Poplar from for very cheap.  I can get it sawed any size up to 16' long.  I'm planning on 8"x8" right now as that is what is drawn.  Which species will be most stable and best to work with?

I really need to know what part of the country you are in to answer better, but if the Polar is Tulip Poplar then it wood be my first choice, with a close second being the YP, if from sound strait logs.  However, Oak is grand, just heavy, and a lot to handle if its your first project.  Log selection is critical for timber framing, but we can get into that latter.  Your sawyer will help if he gets to see your design.  Also, what are your building restrictions?

2. I have drawn the perimeter beams all less than 8' long since they must be man-handled inside the building with the joint sitting top a post for strength.  They are currently drawn as lap joints, but I'm open to suggestions for better joints.

They should be continuous if possible and if not, as the frame evolves the scarf placements will reveal themselves.

3. How can I efficiently adjust the frame where the cross beam that supports the loft and stairs ties into the perimeter beams on the side opposite the stairs?  The inset area making head-room for the stairs terminates that end away from a post making mortise and tenon a good choice (I think), but the other side is a little more difficult.  Suggestions?

I'm still playing with that section.

Regards,

jay

[appster99]

Hi Witterbound.  That is a pretty good idea with the knee walls.  They will be easy to add.  I also thought about the load points and the inspector didn't have an opinion since the project is so small. 

Jay, I'm in the foothills of northwestern NC.  To the best of my knowledge the poplar here is commonly referred to as tulip poplar.  I don't know that I can tell the difference if it is some other type.  The sawyer should know if it is different.  I'm not sure what you are asking for with regards to building restrictions.  I can tell you that my building inspector is very lenient.  He likes what he has seen so far but wants to make sure of the strength of the spans since he isn't an engineer.

With regards to the scarf, the project is small by most standards, but big in that the beams have to be manhandled.  That's why I'm trying to use smaller beams.  If I really need to use full length, which may be harder to get locally, I'll do it begrudgingly.  I'll just have to enlist more strong backs.

I'm redrawing the post in a different location than the sketch posted.  I'll move straight across from the one on the opposite side.  That lets me put the scarf over the post but the crossbeam tie-in three feet past.

Keep the feedback coming!  I appreciate it.

[jander3]

Great start.   Down the road life is much easier if you take the time to install TF Rubies and learn the basics.  When it comes time to cut, rubies produces both a materials list and shop drawings.

There are also tools with TF Rubies that will speed up the process that are not available in standard sketchup i.e. peg holes and stretch tool.

When you are making up your drawings each beam or post should be a component.   When you get one component correct, you can duplicate as needed (often you will need to rotate it to keep your reference faces correct).  That way when you make changes to one component you change them all at the same time.    As you get further along, you will reach a point where you make the components unique (when you don't want the changes to apply to all). 

[appster99]

Thanks for the info Jander.  I'll research and learn to make components.  I did all rafters and joist the hard way - setting measuring lines and basically connecting the dots.  I still enjoyed it enormously!  Its time consuming but a lot of fun for me as I am a huge stickler for attention to detail.