joists in room rotted at external wall - how can i repair

[marialyons]

Hello, I was wondering if there is anyone that can help or advise with regard to ....rotten joists upper floor, no creatures just rotted underneath outer wall...suggestions so far are to put an rsj along the joists from the lower floor which will visible and have to be boxed off. These joists were sistered already about 50 years ago (old building) I think aluminium kits may be an option but not sure. I am told the joists / new with aluminium will have to go back underneath the outer wall to support the wall (nearly all of them are either rotted or eaten by 'rats') and all the cement underneath seems to have fallen. This could be done from the 1st floor with perhaps less invasiveness, than the lower floor approach.....but would like to do the better option. From the centre of the room extending about 8ft to end of the room, the floor has lowered approx 2" ....Can anyone tell me what might be best option please...I would be very grateful. Thank you

 

[^woody^]

Can you cut the rotten timber off and then hang the joist on a joist hanger into the wall?

If not bolt a similar depth joist about 1m long to the side (or each side) of the joist, and hang this off a joist hanger