How can I fasten a threshold to concrete?

Question

BACKGROUND

A threshold was purchased from HomeDepot:

The item comes with screws and needs to be fixed into concrete slab. I would like to understand how to properly screw the threshold into the slab. If it were a wood surface I might drill a pilot hole or use a wood screw, however, given that this is concrete, I get one shot at getting this installed correctly. If not then, it creates a whole new set of problems.

QUESTIONS

• What is the correct procedure to screw the threshold into a concrete floor?
• Is it necessary to drill a pilot hole? The screws are not wide.

UPDATE: screws were misplaced so maybe tapcons may be used

Answer 1

There are two recommended approaches:

1. Use plastic plug anchors. Use a hammerdrill or rotary hammer to drill holes sized for the plugs--typicaly in the 5/16" to 3/8" range. Drive the plugs in with a hammer and run the screws into them.
   
   The advantage of this approach is that you can use a variety of screw types, depending on your needs, as long as they're the right size for the plug. Also, the plug can be removed and replaced if necessary. A disadvantage is the larger required hole size.
   
   
2. Use masonry screws. Pilot holes using a hammerdrill or rotary hammer according to the manufacturer's specifications. Drive the screws directly into the concrete.
   
   The advantages of this approach are the smaller hole and greater holding power. Disadvantages include difficulty in driving the screws, the chance that the screw strips the concrete, the non-reusable nature of the system, and the limited head styles.

With both approaches, precise hole placement is critical. There's virtually no adjustment in position once they're drilled.