Framing a 15 Sided Building

Now that we have a level base, we can start putting up walls. When I was drawing up the plans for the building I just made it look nice, I didn’t pay much attention to things like standard lumber sizes. Luckily my dad was helping us out with the framing and pointed a few things out from his construction days that really helped make this go a bit easier.

  • We built each of the 15 walls to the exact dimensions of a 4’x8′ piece of ply wood. The less we have to cut this foundation grade lumber, the better (toxic saw dust).
  • We would have to fill gaps later with additional 2×4’s, but this would just add to the strength of the walls.
  • We built the floor on piers. This allowed us to maximize our ceiling height, while providing a solid floor that will distribute the weight of all the water tanks.
  • We spaced the floor spans so we could aways land a full sheet of plywood squarely on the edge of each span. This made sure we didn’t have any unsupported plywood that would cause the floor to bounce and made it easy to screw down.
  • We used a string across each floor span and leveled/compacted each pier.
  • We paid special attention to the left side that would support the water tanks and the piers in the middle that support the interior columns.
  • We started the plywood in the middle of the floor so we could use as many full sheets before we needed to start fitting the odd angles. This saved time and materials.

As you can see, we put cross pieces between each floor span. This is to prevent the bottom part of the building base from caving inwards from backfilling. We’re supported from the top, left, bottom, and right with hurricane style ties to reinforce against any lateral tension forces.

The cross pieces are required as part of the wood foundation spec. The forces the earth puts on your walls as you backfill is the main consideration for most of the details with this technique. With a concrete slab and block wall, they’re strong enough on their own.

One thing to note about treated lumber. You have to use stainless or coated fasteners otherwise the chemicals in the wood will corrode your screws/nails causing structural failure. We used exterior deck screws throughout the whole building just to make doubly sure that this thing wasn’t going to move.

We also laid out some thick plastic sheeting we’re using as a moisture barrier. With any foundation (wood or concrete) there is always some form of moisture seeping up from under the structure. A concrete slab does a decent job of preventing this, but with wood you need to add the plastic as well as a foundation vent or blower to give the humidity a place to escape.

This is a good start, but we have a ways to go. Next up is the second floor.

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