Expert: Bruce E. Johnson - 7/17/2009

Question
QUESTION: Hello there Bruce,

In my capacity employed as a maintenance person at a tourist/visitor center, I've been assigned the project of building a shuttle bus stop shelter where three maybe four people typically will wait inside for the bus.  Main requirements are that it be constructed of commonly available lumber/materials, and be free-standing and moveable (so a forklift could get forks under and move to a storage location during the off-season).  On doing a little online searching for plans for such a project, I've come up with a basic design to use and which also has met with approval pending a few modifications. The plans as shown on this site, a lean-to design, are basically what I would follow:  http://www.hometips.com/diy-how-to/leanto-shed-build.html

The plans describe that such a lean-to could be constructed against another structure or be freestanding.  In my case, as I mentioned, it will be a freestanding building, and would be build upon the pressure-treated 4x4 skids as shown in the drawing. The primary modifications I would need to make to these plans are to have one side completely open instead of the large door opening, and to have the open side be the high side instead of the low side, as shown.  Also, I need to expand the size of the structure in comparison to this plan so that I end up with an inside floor space of eight full feet by five full feet.

My abililities/experience are adequate for cutting the lumber to size and assembling by following basic plans.  I am hoping you might be able to suggest specifically how I should handle the modifications, especially in regard to how the plans and assembly would change because of the completely open high side and how to make sure it's solid and stable because of that.

Thanks!  Steve

ANSWER: Hi Steve, basically you frame up the entry similar to the window shown on the drawing only make it bigger.  Because the width of the opening is now close to 8 feet the header needs to be a double 2x8 or a 4x8.  Instead of using beveled studs I would just notch the rafters to fit the top plate.  I have included a simple drawing.  Please feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com

---------- FOLLOW-UP ----------

QUESTION: Thanks for your reply Bruce. In followup may I ask why you suggest using notching (birdmouths) the rafters instead of mitering (beveling) the studs?

Answer
Hi again Steve, the main reason I said I would notch the rafters is because with a big header at the top plate your top plate will be flat.  Of course if you are going to lower your header a foot or so then you can bevel the tops of your studs and the short studs above the header or you can keep your top plate flat and rip a bevel on another top plate for your pitch.  For me, cutting a birds mouth on a handful of rafters is a little easier, I make a pattern out of one rafter and use it to mark out the rest of them.  Also a beveled stud top makes the top plate at an angle and so your top plate will stick out at the top on the inside and in at the top on the outside of the wall.  But really it is up to your preference.   Please feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com