Construction> A Case Study  A Good Old Fashioned Barn Raising (Part 1) We had an opportunity to build a barn North of San Antonio, Texas. This was not to be just any barn, but one 40’ wide by 80’ long with a rear plate height of over 14’ and a front height of 24’. It would have five garage doors: the smallest pair starting at 10’ wide by 7’ high to the middle door being 12’ wide by 14’ high with arches over each one. Add in 3 windows and one set of double entry doors and that pretty much defined the structure to be built. Amazon Forms wanted to use the opportunity to try some new installation techniques we had been discussing as well as we were curious to find out just how good our product is, and what improvements we could make to reduce the total cost of a finished wall. Wanting to put ourselves in our customers’ shoes, we formed a construction team consisting of Bill Bowers, Bill Stipanovich, two production people from the factory (that we rotated in and out over the days), and Randy Carroll-Bradd, the crew leader. Because of the 24’ finished height, we decided on doing two pours, one at a height of 12’ and one to finish the structure. We developed checklists of materials, tools, and supplies as well as equipment we thought would help us reduce the time and cost of the installation. All personnel had virtually no experience installing Grid-Wall.   Before the Installation The barn slab was engineered by a professional engineer and poured with half-inch vertical rebar protruding from the slab approximately 32” in length on 16” centers to accept the Grid-Wall and Grid-Corner blocks (see the block drawings under the “Products“ section to get the exact dimensions). You can tie in this rebar before the pour, insert your rebar in the wet concrete, or come back later to drill and epoxy them in place. We allowed the slab to sit and cure a little since we planned to be working on the slab surface with material handling equipment.
Rebar being installed in slab as poured.			The finished slab awaits our arrival.
Day 1 – Getting Started Steel Garage Door Frame Day one consisted of moving the blocks from the drop point on the road to the slab. We worked on the slab rather than in the dirt as the terrain surrounding the slab was very rough and would require all-terrain scissor lifts and forklift, significantly increasing the cost of those rentals. Pallets of corner blocks were placed in the corners where needed, and wall blocks were placed near their point of use. The garage door frames had been previously assembled from 6” steel channel and the entry door and window buckings were constructed from 2”x10” lumber. Since the garage door frames or buckings were made of steel, we welded rebar on the vertical frame members spaced so as to tie in with the rebar between the courses of block. These frames would be permanently attached to the building
Double Entry Door Bucking		Window Bucking
Rings were cut from 2” diameter PVC approximately 2” long and slipped over the protruding rebar from the slab. The rings will be used later to help keep the vertical rebar centered when it is inserted prior to pouring the wall.
PVC rings on slab rebar		The first course is installed
The first course or row of blocks is the most important to place. If it is not plumb or vertical, then your wall will not be. We snapped a chalk line 10” in from the outside edge of the slab to help us keep the wall straight.
Measuring in 10” from edge of slab		Snapping a Chalk line for the first course
We started with placing the first course of all the corner blocks and then used them to set up a string line to aid in placing the wall blocks. We used bubble levels to check to insure that the blocks were plumb to the slab and, if not, shimmed them until they were. Do not drive the shims in but rather lift or tilt the block to accept the shims. We also had drywall saws so we could level the block by sawing the horizontal seam to remove material rather than shimming on the opposite side.
Setting a string line		Leveling the first course with shims
Once we had the blocks plumb and in a straight line we spot glued them in place so that they would not shift or move when the next course was placed on top. We then moved on to placing the horizontal rebar.
Spot Glue the course to prevent shifting		Tying the rebar with overlap in corners
We used either 40 penny nails or half inch rebar cut into 8” pieces to serve as rebar supports (chairs), placing one in the middle of every wall block and two at each corner block. When we ordered the rebar, we had some cut and bent 90 degrees for use in the corner blocks. We placed the sticks of rebar and the pre-bent corner pieces on the rebar chairs overlapping the ends and wire tied them all in place. We then repeated the process – stacking, leveling, spot gluing the blocks, and installing the rebar. 40d nails used as rebar chairs to support horizontal rebar placed on each course. When you add another course the 4’ bubble level comes in very handy. Use it to get the course plumb but also use it to line the block being placed up with the one below. It can also be used to make sure that the blocks continue to be stacked in a straight line, though we found resetting your string line for the next course worked best. The blocks may get damaged in shipping or handling but are easy to repair. A corner may get broken off but can be repaired quickly. If the broken piece is large and not lost, just glue it back on. Otherwise, use the drywall saw to shape the hole into a shape you can cut a plug for. Cut the plug from a piece of scrap so that it fits snugly and glue it like you would when you stacked and leveled. After the glue has set, check that the plug is tight by firmly pressing against it – it should not move or deflect. Gaps up to about 1 ½“ square can just be filled with glue. (picture of a plug) By the end of day 1 we finished 3-4 courses around the perimeter which got us to a height of 4’ to 5’-4”. We did avoid the front of the structure where the garage doors were as we needed 5-6 courses run before we could set the door frames in place. Not bad, considering we did not place our first block until around 10am!
Day 1: Three to four courses high		Door and window buckings in wall
Day 2 – Progress, Progress, progress After about 5 courses, we brought in two rented scissor lifts to work in conjunction with the rental forklift that we already had on site. This was one of those things that we wanted to do differently than most install crews do: At a normal plate height of 8-10’ they might use wheeled scaffolding to get around. There would be one to two workers on that scaffold with one to two workers handing them blocks and repositioning the scaffold as they went. If they used a scissor lift, it would be lowered so a quantity of blocks could be loaded on the lift, and then raised back up to the working level. Blocks would be placed, and the lift lowered back to ground level for more blocks. Rarely would there be a forklift on site other than to offload the pallets from the delivery truck. We had a 5 person crew with 2 people in each electric scissor lift and 1 “gofer” person on the slab driving the forklift and supplying the scissor lifts with blocks, rebar, ties, etc. The forklift was able to continuously position the blocks at the height the people in the scissor lifts needed to efficiently stack the blocks. One scissor lift crew stacked blocks while another followed behind, leveling those blocks and spot gluing them in place. The first lift crew then came behind the second, placing rebar and tying it while the second lift made another pass to place the next course of blocks. We moved people around to cross-train and keep the progress moving forward. If we were running behind in one part of the process we would get some help from a crew that was running ahead. We kept repeating this process until we placed the majority of the blocks. By the end of the second day we had the majority of the building at 7 courses (9’-4”) with the exception of the front of the building where we had just started to put the garage door frames in place. The double entry doors bucking and the window buckings were all surrounded by Grid-Wall at this time. This would be normal plate height for most residences and the amount of block stacked at this time would have been enough to complete a 2100 square foot house.
Day 1: Three to four courses high		Door and window buckings in wall
Continue On to Day 3  (Part 2) > >