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- Encinitas, CA
Sometimes the scope of work at a jobsite exceeds conventional installation. The medical facility we were working at is at a historically interesting site. They included a few bricks from the original building in the courtyard wall and had a commemorative plaque made telling the significance of the exposed bricks. We were asked to install the plaque. I have to break this post in half because there are more than ten photos.
The job posed several challenges:
An exterior concrete wall.
A thick metal plate with holes already drilled.
The necessity to have exposed screws.
The requirement that the installation be theft deterring.
Our solution was to use stainless steel "spanner head" screws. These screws sit flat to the surface and are driven using a special bit that is rather uncommon. We also used RTV silicone on the back of the plate which would allow the plate to be removed/replaced if desired (due to weathering or vandalism), but would add an additional level of security. The plaque was in an interior courtyard and there is 24 hour security on premises with video surveillance. Construction adhesive such as PL 200/400 or Liquid Nails would have been more "permanent" but would have also meant difficulty in removing the plate in the future.
These are the spanner head screws and appropriate concrete anchors and the carbide tipped drill bit we used for installation. Looking at this photo I can see that my bit is becoming rounded and will either need to be sharpened or replaced. A sharp bit is compulsory if you want accurate hole placement - as is required in this installation.
The anchors are Toggler Brand #AF5 - which are the modern replacement for the lead anchors we used to use for concrete.
This is a spanner head screw showing how the special bit inserts into the screw to drive it. There are two head types available, a "flat head" (for countersunk applications) and a "surface mount head" which sits above the surface of what is being attached - but the head is also flat.
The location of the plate is marked on the concrete wall. We prefer to use tape as changing the marks is easier if the layout changes.
The centers of the holes are punched into the concrete to prevent the bit from walking. We use the "envelope trick" to capture the concrete dust.
I use a rotary hammer drill in concrete. To start the hole, I do not activate the hammer function so the bit stays true to the punched location. I also use the "stop" built into the drill so I do not unnecessarily over drill the hole depth.
The stop sits flush with the wall when the bit reaches the proper depth.
The anchors are inserted into the wall.
I prefer 100% RTV silicone.
......continued
The job posed several challenges:
An exterior concrete wall.
A thick metal plate with holes already drilled.
The necessity to have exposed screws.
The requirement that the installation be theft deterring.
Our solution was to use stainless steel "spanner head" screws. These screws sit flat to the surface and are driven using a special bit that is rather uncommon. We also used RTV silicone on the back of the plate which would allow the plate to be removed/replaced if desired (due to weathering or vandalism), but would add an additional level of security. The plaque was in an interior courtyard and there is 24 hour security on premises with video surveillance. Construction adhesive such as PL 200/400 or Liquid Nails would have been more "permanent" but would have also meant difficulty in removing the plate in the future.
These are the spanner head screws and appropriate concrete anchors and the carbide tipped drill bit we used for installation. Looking at this photo I can see that my bit is becoming rounded and will either need to be sharpened or replaced. A sharp bit is compulsory if you want accurate hole placement - as is required in this installation.
The anchors are Toggler Brand #AF5 - which are the modern replacement for the lead anchors we used to use for concrete.
This is a spanner head screw showing how the special bit inserts into the screw to drive it. There are two head types available, a "flat head" (for countersunk applications) and a "surface mount head" which sits above the surface of what is being attached - but the head is also flat.
The location of the plate is marked on the concrete wall. We prefer to use tape as changing the marks is easier if the layout changes.
The centers of the holes are punched into the concrete to prevent the bit from walking. We use the "envelope trick" to capture the concrete dust.
I use a rotary hammer drill in concrete. To start the hole, I do not activate the hammer function so the bit stays true to the punched location. I also use the "stop" built into the drill so I do not unnecessarily over drill the hole depth.
The stop sits flush with the wall when the bit reaches the proper depth.
The anchors are inserted into the wall.
I prefer 100% RTV silicone.
......continued
