I am trying to get some brick repair done to my home and the contractor wants 50% up front.

Is this the norm? I just don't know. How do you know they will still get the work done?

Thanks! 

There's plenty of reputable contractors/re-modelers who don't require money up front, but often charge higher fees. If anything, get him to provide a materials quote and pay for that directly with delivery set up to your house. Don't pay his labor until done.

Not to say your guy is a bad guy as a lot of small independent contractors operate on a job to job basis with no working capital to float the job. Just check out their references etc and cover yourself. 

I always required 60% up front. But I wouldn't take a check until we arrived and started work, sometimes I didn't ask for a check until the second day and we left our tools on the job every day. Additionally I always gave my customers a long list of jobs recently completed. Just make sure he is local and has a good reputation. He should have a list of recently completed jobs in the area and you can call those customers. Look for a time line, like where were you working last week, the week before and so fourth, if the timeline has a long space between customers possibly he has some bad jobs that people weren't satisfied with. We all have those customers, can't please everyone, but that should be rare, especially if a company is like myself, I live for a satisfied customer, they help me to sell the next job. Very Valuable! 

1/3 is normal. Mostly foraterial costs. 

I wouldn't pay anything up front. I might make progress payments depending on the size and complexity of the job.