I ripped up the drywall in our basement (supposedly built 20 years ago or so, but definitely built over 5 years ago) this summer. I remember inspecting the kiln wood joists and they all looked in great condition.

However, during this winter it seems like there has been some checking and cracking going on through the wood.

First issue:

I have a very long crack going through a spiked knot in a floor joist and the knot appears to be existing across the entire joist:




it appears the crack is affecting the other side of the joist as well:



The builders used 4 floor joists together as the load bearing beam. it appears one of the joists that form this beam has a knot crack that is at least 1-2 inches deep. However, i cant see how far up it really goes (for now, i put a temporary jack post there):



Lastly it appears that my bridging boards along the walls have checked along the nails and popped:




Any recommendations on how i deal with this?

Thanks!

 

Wood will crack, it's not surprising. Since your crack in your first photo has not even reached the other side of the wood, it is nothing to worry about.

The little crack at the knot in your 4 member beam is also very minor, nothing to worry about and you definitely do not need a post there.

The boards in your final pictures are not structural and could be removed completely. Looks like someone tried to bust them out and gave up and left them. They look like they may have been put there as blocking (it's not bridging) for a wall top plate (or maybe drywall) at one time, which has since been removed. Also not an issue.

 

Would have to agree, nothing I see in the pictures is exceptional or anything that I would consider repairing/replacing.