Agreed...at construction sight is probably impractical. The other two questions, as I understand them are: cc'ing to sight, removing and replacing at the end of the day-and retention while cc'ing.
Let's address cc'ing to and from sight first. Several people have addressed this with IWBs with "pull the dot" and metal clips to belt-wear to sight, remove and safely secure in vehicle...and reverse at the end of the day. I agree, but the OP's situation might be somewhat unique, as he works compnstruction. There are quite a few good IWBs that allow for relatively quick removal and replacement...normally these would be great but for clarification from OP:
-Does your IWB or intended IWB require a size larger waist in pants? If so, in your environment you might be pretty uncomfortable towards the end of the day.
-Do you tend to work in cool and comfortable environments, or are you and your clothes sweaty at the end of the day? Replacing an IWB when you and your clothes are soaked will be a bit more difficult and not good on weapon or holster.
This would lend itself to a kydex holster or a paddle. Good ones are available...and can be had with retention devices.
If you are planning to drive to and from work only, a paddle such as the Serpa may suit you best. You can invest in better concealment options for off work time.
Retention...
This is a subject not discussed enough in general. With typical CCW, the weapon is or should be concealed well enough to not present an invitation...If someone can see the weapon and wants it, you need to be prepared...good leather IWBs should hold the weapon in place with normal activities, so if done right, a weapon sliding across the floor is less of a concern...but you must plan your activities accordingly.
Retention should be on your mind at all times...an elbow over the weapon and standing weapon side away from people are good starts. If you are still concerned, a thumb snap release will hold the weapon in place better...but don't let it give you the false sense of security. Situational and weapon awareness are your best friends.
The first weapons retention class I attended was a week long and ended in a broken wrist.
There are civilian classes that address weapons retention and CCW very well...Shivworks and Craig Douglas standout in my mind for this training, and I'd highly recommend it. Craig was an instructor when I was in the academy years ago.