How to Build Slipform Barns

Pour the Slipform Concrete Walls

• 1

  Stake out the dimensions of the barn and dig a trench three feet deep all around the perimeter. Cut the 2-inch by 4-inch lumber and the 1-inch by 12-inch lumber and frame a 2-foot thick footer two and a half feet deep. Pour the concrete up to the top of the footer and level it off. Allow it to set up for seven days.

• 2

  Construct six 8-foot slipforms and four each of 4-foot and 2-foot size. An 8-foot slipform is 2 feet by 8 feet. Make the slipforms from 3/4-inch plywood nailed over 2-by-4s laying on edge. Cut four 2-by-4s for each slipform and nail them at squared corners with 16d nails, then cut and lay the plywood and nail them tight. Measure, mark and drill 5/8-inch holes through the plywood at two, four, and six feet from one end and midway (one foot) up the height. Most of the pouring will be in the 8-foot forms, with the smaller forms for use around doors and windows.

• 3

  Start on a back corner of the structure. Lay the first 8-foot pair of forms, plywood-side facing each other and 12 inches apart, sitting flush on the top of the footer with its trailing end four feet from the corner. Tack a scrap piece of plywood to the trailing end to prevent the concrete from leaking that way. Run 1/2-inch by 13-inch carriage bolts through 2-inch washers, the plywood holes, then through 12-inch pieces of 3/4-inch PVC pipe held between the plywood walls and out the other hole to be washered and bolted tight. This keeps the walls plumb and straight, allowing the bolts to be removed, with the pipes remaining in the wall.

• 4

  Pour the first fill of concrete into the form and up to the top, with the leading edge slanting downward and unfinished. As the concrete is being poured, insert pieces of split face stone against and facing the outside plywood surface in the slipform. This is a practiced art that is quickly learned. Be sure not to stack pieces of stone on one another as they will fall into the concrete. Instead, stack a course of stones at the bottom of the form before pouring begins and, as the concrete rises in the form, add more courses of stone, fitting them into and against the previous course in a closely-fitting, attractive pattern. The weight of the concrete will hold the stones until setting begins. Insert wall-high 1/2-inch rebar rod into the wet first-course concrete every 18 inches.

• 5

  Allow the concrete to set for two hours. While it's setting, set the next 8-foot pair of slipforms beside the poured ones and spike the 2-by-4 ends together with a 16d nails halfway. Pour the second pair of forms full of concrete and wait one hour before pulling out the tacking nails.

• 6

  At the two-hour setting mark for the first pair, pound gently on the sides of the form, unbolt the carriage bolts and pull them out, saving bolts and hardware. Slide the first 8-foot forms up and resting on the first poured wall segment and bolt them together again and repeat the process.

• 7

  Repeat the process all the way up the wall height and down the wall--all the way around the barn, using the smaller forms at windows and doors. Construct 3-foot and 1-foot panels to be connected on the inside of 4-foot and 2-foot panels, respectively, for pouring corners. Use a masonry bit to drill holes around windows and doors--depending on size and dimensions--while the concrete is still soft.

Construct the Roof and Interior

• 8

  Pour the concrete slab interior and snap lines for the location of J-bolts to support vertical beams. Insert the J-bolts. Allow seven days for the concrete to cure. Erect the 6-inch by 6-inch vertical stanchions onto the concrete post anchors and connect them to the J-bolts.

• 9

  Drill 3/4-inch tap holes vertically into the top surface (sill) of the last course of concrete. Bolt down standard size trusses from the front to back of the barn. Erect a king post running from the top of the front truss to the top of the back truss, connecting it to all the other trusses. Frame and nail the king post, rafters and eaves. Use 2-by-6s for rafters; 2-by-12s for the king post and all other structural members. Lay on 3/4-inch plywood sheathing, tar paper and shingles.

• 10

  Square, cut and nail all the outside materials or shingles--front, back and sides. Frame, cut and install the stall separators and gates. Rough in the interior spaces of the barn, including tack, storage, offices, grain bins and other spaces as designed.

• 11

  Install all interior and exterior doors. Install both wiring and plumbing lines. Attach lights and plumbing fixtures.