Step 7 : Anchoring Base Rails

You will notice in this step there is a different voice narrating this assembly step. That is because at Absolute Steel we are continually improving our product and this step of the installation process is one of those improved areas. Previously the base rails were pre-drilled in the center and the wedge or concrete anchor was inserted into that hole and that’s where the concrete anchor secured the base rails to the concrete. The difference now is that we use a Z clip which is affixed by frame screws to the base rail and then the Z clip is secured to the concrete through pre-drilled holes by 3/8ths x 3 ¾” concrete expansion or wedge anchors.

This causes the concrete expansion anchor to be used approximately 4 ½ inches from the edge of your slab if your base rails are 2”x3” and 5 ½” if your base rails are 2” x 4” as found in our HD or Heavy Duty buildings. Before the implementation of the Z clip the anchoring occurred 1 ½ to 2 inches away from the concrete slab’s edge. This improved positioning of the anchors ensures the concrete is not fractured, cracked or broken at the edge when the anchor penetrates and is tightened to the concrete.

Most of our buildings use a 3 3/4 inch x 3/8ths inch concrete expansion anchor. In some cases, like the coast of Florida which has excessive Wind Loads, a larger anchor may be called for or you may be required to use additional number of anchoring locations. If that’s the case, they will be supplied with your building and your instructions will clearly indicate that you may have more anchoring positions.  Make sure you use the proper sized masonry bit for the anchors that come with your kit. Half inch for a half inch anchor and so on.  Check the bolt manufacturer’s instructions for specific installation recommendations.

You would now align and place the base rails with the chalk line and the reference marks that are on the concrete. In the case of a square and true slab you would align them along the edge of the slab. Use a hammer to tap them into position if necessary.

When all aligned, use Tek or frame screws to affix the Z clips to the base rail. Place the weight of your foot on the base rails when you do this so the base rails are not moved.

Next drill your anchor holes into the concrete right through the predrilled holes of the Z clips, placing your foot on the base rails to hold them in place while you do so.

Before you insert the concrete expansion anchor, place a flat washer on the bolt and thread a hex nut on the top of the bolt until about a quarter of an inch of threads are exposed above the nut.  Now, with a hammer tap down the expansion bolt and then tighten the nuts with a wrench. Continue this until all the predrilled holes in the Z clips are securely anchored.


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Step 8: Wall and Roof Frames to Base Rails

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