On a 3,7m span, 44x195 C16 @400c/s will be fine. (by way of comparison, that section-size will span 4m for a floor, which carries about twice the live load of a flat roof).
If you need to find a tradesperson to get your job done, please try our local search below,
or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Please select a service and enter a location to continue...
Are you a trade or supplier? You can create your listing free at DIYnot Local