how much can i trim off a joist ?

[tomerny1]

Hi there, i am currently doing my loft conversion and about to put the joists in. The span is under 4 metres outside wall to internal load bearing wall. But at the outside wall i will have to cut joists at an angle to fit them in. I'm using 8"x2" timbers. The ceiling joists are 3"x2". I will probably have to cut joists down to 3" at the end. Does anyone know if i can do this.? or if there is a way of strengthening them at the ends ? Any help would be appreciated.. thanks...Tom..

[welsh brickie]

obviously you need to cut them but keep it as tight as possible to the angle of the roof,there is no other way.

[tomerny1]

thank you. was also thinking of using "restraint strap" to tie joist to rafter. thanks again...

[andy01]

you proposing to reduce the depth of the joist from 8" to 3". The shear is greatest at then ends and should be checked to ensure the timber does not fail. The structural engineer you are using to provided the required calcs to building control can check this out for you.
I would use JJIs or FJIs with the proprietry end supports for just this occassion, less calcs involved then