So I have some roofers creating a balcony roof for me and midway through the build, my architect/structural engineer who is working on another project on my house took a look and had some concerns. He said the constructed frame in the photos below was not sufficient in his opinion for a roof and even more so one that would be used as a balcony with foot traffic. His main concern was the direction of the joist and that the endplate over the doors to the right only consisted of one 200x50 board. This is the end the water will run off into a gutter. He also pointed out the board running along the garden retaining wall had a gap behind it as highlighted with the arrow below. He advised me that the load-bearing plates should be attached to the wall of the house and the garden retaining wall with the joist running between them in the opposite direction to what they are running in the photos above. Illustrated in his drawing below. He said the board above the door should be made up of at least two boards fastened together with coach bolts and they should also be attached within the plates like his drawing above shows and not on the ends, he also said the boards should not rest on the aluminium frame of the doors at all and there should be a gap. My builder has made the changes but is saying that the advice given is wrong and there was nothing wrong with the original frame, he also states that the way the structural engineer says it should be done is much weaker than his original frame Here is an image of the updated frame that will be lifted slightly and fixed to the retaining wall and the house where the photo is taken from, note the double boards above the doors have been attached to the end of the frame not within it as per the drawing above. What do other people think about the above situation, I'm not a builder so I dont know who is right and I feel really awkward in the middle of it all, I just want a GRP balcony roof that's going to be strong and last the 25-year guarantee that is being placed on it. I thank you in advance for any input helping me understand who is right.