i beam size

[happyman1010]

hi have scan though loads of mail but cant find any thing
trying to find what i beam i need for a 6 mt opening ( bi fold doors) on a conservatory with a slate roof, the conservatory size is 7mts by 3.5 mts internal, with a 15 deg roof
found the roof timber size in other mail looks like i need c16 175-50 so will use 200-50 c16 to give me a bigger safety margin,
also do i have to sit the roof timbers on top of the i beam ?
can i use the web ?
regards
rob

 

[jeds]

All the loadings need to be calculated. When you know the loadings you can calculate a beam. You will need calculations for building control.