The fact you used to smoke dope at work on the regular but you still felt the need to ask this question means you should absolutely not be taking that dose of valium before work if you value your job, your life and/or physical well being, or the lives and/or physical well being of your co-workers. Yes the people who interact with you regularly will definitely notice a difference, even if you dont appear sleepy or wasted, you attitude will be totally different. You will have lower inhibitions, take more stupid (and in roofing most likely dangerous) risks and you will be slower in movement, speech and thought. They might not realize why but they will notice a difference.
You said you used to smoke dope at work everyday, are you clean from dope now? Are you clean fron all opiates? If so, how did you get clean and how long have you been clean? If you're not clean - mixing opiates and benzos is extremely deadly. I smoke dope now and back in the day I smoked oxys and roxies - all the people I know who died from OD that didnt use needles, ODed fron mixing opiates and benzos.
Either way, if you just started abusing valium or benzos daily - be warned- you are standing at the top of a very long slippery slope downhill, benzo withdrawal is horrible, dangerous to the point of being deadly, and wayyyyy different than opiate withdrawal. I know you wont stop what you're doing from me y no mi ni j8g to work BnB n gon l but maybe it will help someone else who see this thread on Bluelight who has started yet