Building size question

[IMScoop]

I'm months, if not years from being able to build...don't even have land yet but I've been browsing the owner builder forum for a long time. I have zero building experience so I figure the least I can do is start planning. At some point, I'll order some plans but not quite ready, even for that, just yet.

In looking over the plans here, I have sort of a general question. Forgive my ignorance if there is a simple, logical answer to this, but it seems to me that floorplans would generally be in multiples of 4' since dimensional lumber, etc. is most frequently sized that way (i.e. 4', 8').  Why are a lot of the plans not like this?

e.g. the "Little House Plans" include three size buildings - 10'x 14', 12'x 18' and 14'x 24'. Each of these has a width or length that is not a multiple of four. Similarly, the builders cottage is 14' wide and the 1.5 story is 30' long. Is there a reason for this? Wouldn't dimensions like 12' x 16' and 20' x 32' be more  typical and a more efficient use of materials?

[Erin]

Something I've decided is that I can PLAN for efficient use of materials, yet I'll still end up cutting.  Might as well go with efficiency of space and engineering, instead... 

By the way, I started reading here 7 years ago when we were in exactly the same spot.  Nothing was being built, we hadn't even found land yet!  But we're putting the roof on our house next week. 
It'll happen.  Be patient.  (and save more money!  I can guarantee you won't have enough.  )

[Don_P]

There ya go. I can draw a floor on 4' modules... and then the T&G ply locks together at 47.5" and the minimum rip APA allows is 16" wide, there goes a row of sheets. I can make the wall on 4' and then I'll want a roof overhang, so which do I go with? I'd rather the plan stay a little under a module so I don't end up inches short. If you really want to make it work get good with sketchup and draw it stick by stick and then sheath it in the drawing, work out openings to land on on center framing so that the extra stick doesn't have to be thrown in to break a sheet on, etc. The best designers I've worked under have thought through these issues and part way through you realize, this guy was on the ball.

[IMScoop]

Thank you both...that definitely helps me understand a little better. Planning for efficiency of space is definitely important to me and I'm sure with a certain margin of error inherent to any build, it's impossible to have everything perfectly in line and sized exactly.

It does seem to me though that two feet is a lot of "wiggle room" in a ~14' span and contributes significantly to waste. If you were to layout a foundation/platform, say, one inch short for every 12' or so, wouldn't that be sufficient to minimize what you cut with regard to sheathing, etc.? Also, it seems that trimming  something like rafters and joists would be easier and more efficient than ripping sheets of ply. In the "roof overhang" scenario, aren't there other factors that contribute too, like the presence/with of a ridge beam and the roof pitch?

Don_P, what is APA?

Any idea how the various CP plans stack up with regard to the layout of openings, etc.?

[flyingvan]

http://www.apawood.org/

       I wonder how many homes have a 1' wide strip of T&G subflooring because the builder thought 48" sheets were going to cover 4' of flooring......(mine are among them, btw)
       Designing a place around lumber dimensions is a fool's errand.  Cutting wood to size is a very minor part of the building process.  If you're really not concerned with cuts but worried about wood waste, don't be---as you cut stuff just set it aside, stacked according to lengths---those scraps WILL be used.  Countless blocking, fire breaks, and fill spots are in your future.  Often the cut end will be a split or warped part of a board; if you aren't going to use these for kindling in your woodstove I bet you have a grateful neighbor who'd love them.
       My waste pile was small, mostly weird shapes of OSB.  The huge beam cutoffs stay with my prybars as fulcrum points when needed. 

[Erin]

I wonder how many homes have a 1' wide strip of T&G subflooring because the builder thought 48" sheets were going to cover 4' of flooring......(mine are among them, btw)

Probably as many as have doubled up 2x4 studs because starting a sheet of ply/drywall at the edge of the first stud does not result in an o.c. placing on the next one...
Though of course I don't know anyone personally who's done such a thing, and no one can prove otherwise because it's hidden in the wall!   

[rick91351]

Probably as many as have doubled up 2x4 studs because starting a sheet of ply/drywall at the edge of the first stud does not result in an o.c. placing on the next one...
Though of course I don't know anyone personally who's done such a thing, and no one can prove otherwise because it's hidden in the wall!   

Geee Erin I would not have a clue what you a talkin' 'bout ........ from    to   to   I did it to just give the 'rockers' a better nailer...

[akwoodchuck]

Don't be worryin' about dimensions....worry about getting her square, level, and plumb 

[MountainDon]

Don't be worryin' about dimensions....worry about getting her square, level, and plumb 

Yep!

And ditto what Don_P and some others have said.... it's one of the reason our cabin is 15.75 x 30... actually more like 15.82 x 29.89 if I was being precise. That's the measurement before final siding and trim.   

Very little went tp waste; dimensional waste made kindling as a last resort. And I used up scraps of osb over the first few years after the cabin was complete.

[Squirl]

Most lumber will be .25 - 1 inch over stated length and all pieces will have to be cut.  Expect to cut most pieces. One reason is it is generally less wasteful to cut off 1" in length or maybe 5.5 inches for one wall at the corner than 1.5 feet.  If floor joists come in lengths of 12 feet, why make the building 11?  It is less wasteful to have a 1" strip of plywood than 20 joists with a foot cut off.  That is why you will occasionally see building widths an extra 3" because of the rim joist thickness or 9.5 feet of wall sheathing from the floor joist, subfloor, bottom plate, 8' stud, and double top plate.

Also, many lumber yards, but not big box stores, sell 14' lumber.

[Don_P]

It is less wasteful to have a 1" strip of plywood than 20 joists with a foot cut off.

That 1" strip destroys the diaphragm. The rim joist should really be tied to the joists with strips no narrow than 16"

[flyingvan]

Now if we could just figure out why there's 10 hot dogs and eight buns per pack...

[rick91351]

Now if we could just figure out why there's 10 hot dogs and eight buns per pack...

That is easy.  For us that you invite over that do not do carbs.  Or cut the two up and toss into the beans you are serving with the hot dogs ......  Next question please......

[considerations]

Great answer on the dogs!