letter to state that the new constuction is safere

Hello, I have enlarged my house. I added an extention of 12 feet by 29 feet to my house. In my extension, my contractor changed the slope of the roof to higher peak to avoid snow and water accumation. It is okay with the city but I require a letter of recommendaiton that basedon the plan after buildt is better than the one before built. My contractor did not want to add more loads to the existing roof so he made it V for the middle roof and then inverse V for the new extension to eliminate or to have less water, sinow, wind, etc problems. I need a letter of recommendation by an engineer to add to my architect plan to provide to the city. I have the plan of the extension before and after from the dratsman and architect. All I need is a letter to state that the new constuction is safere, more regid as the contractor added H beam and metal support to make the roof super strong. If you are interested, let me know. Thanks