I've had good, long-lasting results using self-leveling polyurethane
caulk over backer rod. I live in the Midwest with cold winters and hot
summers so there is significant expansion/contraction happening.
I just replaced my wood expansion joint. First I cleaned out the
joint. I used PT lumber, thinned it just enough for a snug fit,
stained it using gray decking stain, and secured it into place using
Liquid Nails. After a day, it was caulked using gray caulk. Should
last another 15 years, maybe more.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.