Worn stumps and joists

"Stumps and joists can erode with damp issues, condensation, woodworm.
Joist typically erode when fitted into or next to brickwork.
Solutions are normally to make sure Damp proof membranes are fitted correctly in the walls protect all Joists/Stumps from damp"

"Not sure what you mean by stumps but joists can rot, particularly where they are 'pocketed' into a wall. To rectify this, ensure that the walls are not damp from penetrating rainwater, rising damp or leaks. Then replace the joists.
Joists can be hung from joist hangers instead of being pocketed into a wall and this allows better airflow."

"Could be a number of reasons. Re: have got damp/wet due to damp problem or no airflow so this creates moisture/condensation as they can’t breathe. Woodworm is another possibility.
Depending on the state of the joists... If woodworm, you can apply a sealant to kill and prevent the woodworm from spreading further. If there really warped and wet/damp then depending on how severe they are, you may have to change them. If it’s caused by moisture/condensation then maybe add an air brick and ducting.
Hope this helps.
Kind regards
Mitch..... MML Construction"

"They are worn because of water ingress. Firstly you have to prevent water ingress. Then you have to cut out the joist 60mm past the furthest point of erosion. Then you have to install a wall plate bolted to the wall with joist hangers attached. Then you bolt a new joist to the side of the cut joist ensuring that the bolts will carry the load. Installed into the new wall plate nailed into the joist hanger. The hanger must be nailed with twist nails. I highly recommend you used a construction professional to do the job."

"Seems like they have wet or dry rot can't really
Without looking, you would have to replace them
But if you have a dwarf wall underneath you could probably get away
With just doing from there hope this helps
Steve"