Building Balcony Railing over flat roof 7-11-13 - YouTube Jul 11, 2013 . A great way to build a sturdy balcony Railing. . Thanks, you're right, I couldn't find a good tutorial either for balcony railings so your video has really helped me. Many thanks for taking the time to do this. :-). Read more. Show less. Reply 5 6. Moto Citee3 years ago. how did you fasten the post to the floor?