Sashco Log Builder Caulking

Not all logs on your home move at the same rate; some may move a lot and others barely at all. When they make the recommendation they figure out the most movement you would see out of two logs touching each other factoring in the size of the logs. They recommend a joint size that will allow the stretch to happen without failure. The sealants and chink are designed to strech 2.5x the joint size before failing. Big logs overall move more so require a bigger joint. If you short it too much there may not be enough material to handle the log movement.

Some people want the joint to be smaller due to cost or the look.
For Example: If you took a 1.5" recommendation and went with 1" instead, you will notice a few more repairs over the years if you get two logs that really move. You are not likely to see failure everywhere if you were deep enough with the joint in the first place ( notice we are talking depth here...not the initial joint width question) The smaller you make the width the more likely you will see failures or separation. In our experience we have seen good results if people use at least 2/3 of the recommended joint size...but we don't recommend pushing it further than that.