Friday, September 13, 2013

The Start of my First "Micro-Micro" home: Planning Phase 1

Time to calculate some basic things out.    Based on a Harbor Freight trailer size of 8' by 4', and planning on building out the platform wider to 5 feet wide and 9.5 feet long, we want to figure out what kind of interior space we can get away with.   using 2X4 lumber we will have 4 feet 4 inches wide inside for width and 8 feet 9 inches for the length.  This makes things very crampt.   So the HF trailer is probably not an option.   2X4 lumber typically weighs about 1.5 pounds per linear foot.  so let's calculate out the weight of just the framing... I am assuming 6'4" side walls, and only a 3'2" tall loft area, yes it will be "cozy" in the loft. You really want to say under 11 feet tall total from the ground to avoid any clearance issues when pulling the trailer.

Again using the 5X9.5 above...   60 inches by 114 inches with studs at every 18 inches aprox.  end walls will need 5 studs plus 3 for top and bottom plate.  Side walls need 10 studs plus 3 for top and bottom.   Figure them at 6'4" tall or 76"  so let's calculate the amount of inches of boards just for the lower framing.    76" X 30 vertical studs + 76" X 15 horizontal studs (overestimate a bit)  I get a total of 3420 total inches of 2X4 or 285 linear feet.  Multiply that by 1.5 and we get 427.5 pounds of JUST the wall framing add another 160 pounds for the loft  floor and the roof framing.  we have a total of 590 pounds of wood just for the framing add in another 20 pounds of screws and 10 pounds of glue to assemble it all.  620 pounds and we just got started.

Let's look at the floor, roof and sheathing.  1/2" ply will be good for the roof,  3/4 for the floor, and 1/4 for walls.  Plywood is 3 pounds per square foot per inch of thickness, so 1/2 ply is 1.5lb  and 3/4 is 2.25 with 1/4 at .75  round that to .8  we have 108 pounds in just the floor 3/4  115 lb for the roof and 146 pounds for the wall outside.  989 pounds for just a box with a loft and floor. not including any siding, no interior wall covering, no interior walls, no insulation, no wiring, no windows, no doors.   BUT you can safely fudge that to see that the complete place will weigh near 1400 pounds if you went for very light materials.   And this is for the ungodly small 4' 4" interior width. Here is some perspective on that size,  a very very small cubicle in an office is 6' wide by 6' deep you have just enough room to move your chair to get to your desk.

The harbor freight trailer is rated at only 1500 pounds, so it's straight out unusable,  we can not use it just because of weight capacity, and honestly it's too small anyways.   Time to find a junker camper to get the frame from, I'm thinking a popup camper that is rotted out.  The smallest I recommend is a 6.5 foot wide by at least 10 feet long those typically are rated for around 3500 pounds (old ones) so that will work for our mobile micro home.  I need to find a trashed popup camper or other camper that I can salvage the frame from....

NOTE :The weight calculations are not needed if you are building on the ground as a permanent building,  only a trailer really needs this unless you are thinking of using the cement block piers that have for making decks,  then you need to understand the structure weight so you can calculate out how many piers you will need.   This can be used in some communities to get past zoning laws as the building is not considered permanent if it is only sitting on the ground.

Next we explore the safety and load capacity of 2"X2" lumber that they make most travel trailers and RV's out of...   as well as lighter materials for siding...

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