Fitting velux to monopitch roof, double up on roof trusses?

[bandekk]

I'm just about to fit 3 new P10 velux windows to my single story extension and have looked into the fitting procedure. I've read about having to double up on the roof trusses around the velux windows, (either side, and top and bottom?) but as I have 7*2", this does seem a bit of an overkill? Is this right?

Also is there an easy way to get all roof trusses level when installing them. I know my wall plate and pitching plates are level and therefore should be able to cut all trusses to same profile, but I'd rather be absolute sure before doing this.

thanks

 

[mikric]

What size are your Velux windows and what centers are your rafters ?

 

[bandekk]

hi, velux windows are 940 * 1600, truss centres will be 400....

 

[bandekk]

should also say, roof dimension are 6460mm by 3600mm, so fitting 400 centre trusses means I could easily move then around to suit the velux window requirements.