Wasn't that what the Rabbit said in the fairy tale, Alice in Wonderland?
It's my opinion, that being late is almost always a habit. It's a bad habit. If you're a construction business owner who has the habit of being late, change the habit. If you have employees who are perpetually late, you have to decide how much you want to put up with.
There are times when a vehicle won't start, the alarm clock doesn't work, traffic is so backed up you could crawl to work faster. But those situations are rare and can be forgiven. I remember my dad getting all over one of his electricians because he showed up to work at 9 am instead of the normal starting time of 7 am. Dad ranted and raved, then asked why he was late. It turned out that the electrician had spent most of the night on faulty circuits in a restaurant in town so the restaurant could be back in business for breakfast. Oops.
Your employee manual should state the starting time each day. (If you don't have an employee manual, now's a great time, you can get started with ours here.) You should also include break times as dictated by the state, lunch time and quitting time. You should specifically state what days are considered paid holidays and which aren't. With everything in writing, if an employee shows up late you can call them on it. I think a policy that says they will be sent home without pay the second time they show up late is appropriate. Some contractors I've spoken to would give an employee two days off with no pay the third time. I'm not sure I would go a fourth time.
Call them in, set them down and remind them of the rules. Then enforce your policy. It's your choice how much of this you want to put up with, but trust me, if you don't take a stand on tardiness, you'll soon find your employees taking advantage of your good nature.