Appreciation post: I found a busted expansion joint in a garage floor last Tuesday

I was finishing a garage slab in Phoenix and noticed the expansion joint had this weird cracking pattern I hadn't seen before. Turned out the previous crew used the wrong filler material that dried up way too fast and left gaps. I learned it's worth checking the joint spacing even on small residential jobs. Has anyone else ran into filler failures on older slabs?

2 comments

2 Comments

the_hannah13d ago

That cracked filler issue is a common one in Phoenix with the heat. You're right to check the joint spacing, even on small jobs. I've seen where the filler shrinks and pulls away from the edges in just a few weeks, leaving a gap for dirt and water to get in. That water can freeze in the winter and make the problem worse over time. Best practice I've found is to use a self-leveling sealant that can handle the temperature swings and apply it in cooler morning hours so it has time to set before the sun hits it.

grant.parker13d ago

OH man, you are NOT kidding about the freeze-thaw thing in Phoenix! I swear, one morning I thought my driveway was just being dramatic, then I walked out and saw a crack that looked like it was trying to evolve into the Grand Canyon. I once patched a joint in July and watched the filler practically melt and run away like it was scared of the job. That self-leveling stuff in the MORNING is the only way to go, anything else is just asking for a goopy mess that'll make you question your life choices by noon.