Rotten joist

[Jono11]

Hi

I am in the process of replacing a felt flat roof for epdm due to a leak.
I have removed the old roof boards for replacement with 18mm osb3 and have found one joist which is rotten and by the looks of it was rotten the last time the felt was done as some (rubbish) repair work seems to have been done. There are 8 joists and the 2 walls in a 3 x 3m roof, the rotten one is in the middle.
Would it be OK to just leave it

Thanks
Jono

 

[freddiemercurystwin]

Why go to all that trouble and then leave one duff joist?

 

[Jono11]

Only because I haven't got a clue hot to replace it, there is a board attached to the bottom which I assume is the ceiling, which I don't want to damage.
Or is there a way of replacing it without disturbing the ceiling.

 

[Jono11]

Ok it is a common problem here, so I cut the rot out and bolt a new joist to the old.
When the advise says bolt does it mean nut and bolt or can I use a screw

 

[catlad]

If you don't want to take out the old joist just buy another the same size and fit it close to the other one.

 

[Jono11]

Thanks, that I can do.

 

[ree]

Why not let a roofer deal with this issue?

Dont leave any rotten woodwork in any kind of roof esp a flat roof where, over time, wet rot can "turn" into dry rot. If you suspect dry rot pic and post on here.

Sistering a sound joist to a rotten joist will quickly lead to decay in the sound one.

The ceiling is fixed to most all the joists, and will perhaps be damaged a little when removing a joist.