Moving rafters in existing flat roof

[DerMitchie]

This is a section of my flat roof extension.

The top rafters simply support a suspended ceiling below the original ceiling.

The bottom ones are only approx. 500mm short and are placed inside the RSJ that supports the building and connected to the frame that supports the roof light, I cannot see how these short rafters bear much of the load.

It would help me if I could move each of the two rafters indicated in light brown 100mm in either direction so as to help me fit a ceiling kitchen extractor fan and - more importantly - ducting.

Would this by risky?

 

[sxturbo]

Moving will be fine.

Though be mindful of you are replacing with plasterboard it may sag due to the 600mm gap, so not sure if after you fitted the fans you can put a horizontal Beam in

 

[Harry Bloomfield]

Moving will be fine.

Though be mindful of you are replacing with plasterboard it may sag due to the 600mm gap, so not sure if after you fitted the fans you can put a horizontal Beam in

Could he not install a new one in the middle, before removing the two light brown ones?

 

[sxturbo]

Could he not install a new one in the middle, before removing the two light brown ones?

i would have thought he thought of that already., i just assume its a mighty big extractor as he wants to move them both for a 600 gap.

as for ducting, he could just go straight out the top through the flat roof

 

[DerMitchie]

Thanks everyone and sorry for not replying - I didn't get any alerts. I moved one of the rafters by 15 cm without problems and fitted the extractor. I'm going to drop the ceiling a little, so the plasterboard will be attached to the false ceiling frame. As for ducting out, sadly there just isn't enough space above, so I'm running 204 x 60 flat ducting in the false ceiling and then out of the side of the garage.