That cheap foam backer rod trick saved me on a driveway pour in Austin

I was fighting with cracking on a big driveway job for two days. Tried different mixes and wet curing but nothing stopped the hairline cracks. Then an old timer told me to shove foam backer rod into the control joints before sealing. First pour after that? Zero cracks. Has anyone else used that trick or am I just late to the party?

3 comments

3 Comments

william_craig79d ago

Not late at all, man. The backer rod trick is old school but it works because it lets the sealant move with the concrete instead of ripping apart. Just make sure you're not jamming it too deep - you want the sealant to be about half the depth of the joint.

casey2689d ago

Wait, so you're telling me I've been shoving backer rod in there like I'm stuffing a Thanksgiving turkey and wondering why my sealant keeps cracking? That 'half the joint depth' rule probably explains why that one driveway patch looks like abstract art after winter. Honestly though, I still can't get over how some guys use way too much foam rod and then act surprised when the sealant bulges out like a muffin top. Must be nice to have that kind of confidence in your bad choices.

jennybailey9d ago

Read a study saying proper joint depth prevents 80% of sealant failures, just like @william_craig7 said.