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How to fix a 2+4 Post Lift to a concrete base
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How to fix a 2+4 Post Lift to a concrete base

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posted in Support and Advice - Floor Bolts by Richard Wilson on 13:18 Feb 12th, 2019

An Anchor*/Through Bolt is a mechanical type expansion anchor that consists of four or five parts: the threaded anchor body, the expansion clip, a nut, a washer and a spring washer. It is designed for use in solid concrete only. These through bolts provide the highest and most consistent holding values of any mechanical type expansion anchor.

*Known as Wedge Anchors in some countries

Installing a Through Bolt into concrete can be accomplished by following the directions below.


1. Assemble the right tools

  • A hammer drill must be used to create the hole in the concrete and not an ordinary rotation drill
  • Use a hammer drill set in the hammer and rotation mode. This ensures proper hole dimensions and makes drilling the hole easier
  • Not using a hammer drill will make the hole difficult to drill and may decrease the holding value of the Through Bolt once installed


2. Determine the sizes

  • Determine the minimum length of Anchor/Through Bolt/Wedge Anchor to use by adding the thickness of the material to be fastened to the minimum embedment for the diamter of the Anchor to be installed with space for the nut and washer
  • These Anchors can be installed at deeper embedments than the minimum embedment depth. In most cases, this will provide better holding values
  • Use a quality drill bit that is the same diamter of the Anchor being installed
  • Use bits to ensure proper hole tolerance between the hole diameter and Anchor diameter
  • Hole tolerance is crucial to ensure minimum holding values 


3. Drill the holes

  • Drill a hole that is slightly deeper (a minimum of 13mm) than the expected embedment dept
  • It is important that the bolt does not penetrate all the way through the concrete


4. Check the depth

  • Be sure the depth of the hole is correct. Set the depth gauge on the hammer drill or place tape on the bit at the required depth
  • Make sure that when placing the tape on the bit or setting the depth gauge that the bit is in the retracted position. The retracted position is when the bit is at its most inward position in the chuck


5. Clean the hole

  • Clean the hole of all dust and debris to help ensure proper holding values once the anchor is installed
  • Clean the hole by using a wire brush, vacuum, or compressed air
  • Use a wire brush to clean the hole, and then vacuum the hole. Repeat this a few times, and the hole will be clean and ready for installation


6. Install the Anchor/Through Bolt

  • Each Anchor/Through Bolt should come with the correct number and size of nut and washers
  • Take the washer and place it over the the threaded end of the Anchor/Through Bolt
  • Then take one nut and thread it clockwise onto the Anchor/Through Bolt body until the top of the nut is flush with the top of the Anchor/Through Bolt (lift post) body. This protects the threads of the anchor during installation
  • Install the Anchor/Through Bolt through a hole in the fixture, or install directly into the concrete, and then place the fixture over the anchor


Through Fixture

If the anchor is going to be installed while the fixture is in place, make sure that the hole in the fixture is slightly larger than the designated diameter of the anchor. Insert the anchor, clipped end first, through the hole in the fixture and into the in the concrete. With a hammer, strike the nutted end of the anchor until the washer and nut are tight against the surface of the fixture. Make sure that the anchor is embedded at least to the minimum embedment depth. Embedment depth markings (on some manufacturers Anchor/Through Bolts), help to ensure precise installation of the Anchor/Through Bolt.


Direct into concrete

Insert the Anchor/Through Bolt directly into the predrilled hole in the concrete with the clipped end going first. Strike the nutted end of the anchor with a hammer until the anchor is embedded into the concrete the required distance. Make sure that a minimum of three to five threads are below the surface of the concrete and there are enough threads above the surface to accommodate the thickness of the material being fastened and space for the nut and washer.



In order to ensure the lift or fixture is level, use Shims to make up in discrepencies in levelness. We supply Shims of assorted thickness.


For our range of lifts, we supply the following Anchor/Through Bolts: 



E4G 120150Z M12 x 150mm through bolts

E4G 120180Z M12 x 180mm through bolts

E4G 160150Z M16 x 150mm through bolts

E4G 160180Z M16 x 180mm through bolts

E4G 980 - M18 x 140mm through bolts

E4G 981 - M18 x 160mm through bolts

E4G 982 - M18 x 180mm through bolts


We keep a range of Bosch SDS plus drills with the new 4 head cutter which is capable of cutting rebar to suit our range of Through Bolts





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