Originally posted by Nerevar:

check thier color with the hammer. if they turn deep red they can sometimes break as they lack stability.

note : wait atleast 2 minutes after placeing something for the colors to adjust for new pieces. otherwise they all show green at first. thier color slowly switches afterwards.

This ^^^^ There is quite an art to building in Valheim.. holding a hammer you can see the current state of your build piece by piece just look at the piece while holding hammer.. blue good, red bad and there are heights beyond which you need "iron wood" reinforcing.. normal building and buttressing does NOT help this "weight loading" represented by colour Dark red can hold no more above it.. maybe not even stay up..