Help with roof pitch for velux windows

[Lors]

Hi, struggling to work out if the pitch of a new lean-to roof is deep enough for velux windows. I'm hopeless at maths so if anyone can tell me what on earth this is as a % I'd be truly grateful.

The pergola is 3.4m deep (including rafter ends) Wall height is 10.5ft high dropping to 7ft high posts.

I believe minimum gradient required is 15%. Am I way out? Thanks in advance

 

[Lors]

Hi, struggling to work out if the pitch of a new lean-to roof is deep enough for velux windows. I'm hopeless at maths so if anyone can tell me what on earth this is as a % I'd be truly grateful.

The pergola is 3.4m deep (including rafter ends) Wall height is 10.5ft high dropping to 7ft high posts.

I believe minimum gradient required is 15%. Am I way out? Thanks in advance

Run should read 10ft, not 3.4m but have answer now anyway!