Comments on: Tips for Filling Contraction and Expansion Joints

By: Shea Walker

Shea Walker — Mon, 19 Oct 2026 14:20:22 +0000

In reply to Jim Krebs. Hi Jim. Don't use caulk. It will eventually shrink and crack. Instead, use a polyurethane self-leveling sealant like SikaFlex. You can usually find it at your local home improvement center or hardware store. It adheres well, flexes, and fully seals the joint for a finished look.

By: Jim Krebs

Jim Krebs — Mon, 19 Oct 2026 12:46:12 +0000

What type of caulk should I apply where the newly polysporatic coated floor meets the painted block walls? Would like to dress up the final project. Thanks

By: Shea Walker

Shea Walker — Sun, 06 Jul 2025 17:41:44 +0000

In reply to William. Hi William. You can't make the floor seamless from wall to wall if that is what you are asking. You can only fill and coat over contraction joints. This is what is referred to as the "seamless look". The perimeter joints are expansion joints and must be honored. You don't coat over them. In the latter half of the article we address using self-leveling joint fillers (such as SikaFlex) to fill expansion joints. This should be performed after the coating has been applied and cured. Does that answer your question?

By: William

William — Sun, 06 Jul 2025 15:59:18 +0000

Your article states:
“If you want a seamless-looking epoxy or garage floor coating, contraction joints must be filled with a specialized epoxy or polyurea joint filler that cures hard and with a higher elongation rate than the coating. This provides the required flexibility to help prevent the garage floor coating from cracking at the joints.”
Do you address these products? The photos are of seamless floors, most likely having expansion joints around the perimeter. So, I remove the material between the floor and foundation wall, then what should I do using a different product than say the Extreme 100 I used on contraction joints? Thanks for you time.

By: David

David — Sat, 14 Jun 2025 02:23:14 +0000

In reply to Shea Walker. Thanks! I’ll investigate whether I can get hold of that here in Australia…

By: Shea Walker

Shea Walker — Fri, 13 Jun 2025 15:52:15 +0000

In reply to David. Hi David. Yes, a 100% epoxy or polyurea with some flexion is what should be used in the joints if you want to fill them and grind them flush for a seamless look. Our favorite to use is Xtreme-Set 100 by Legacy Industrial. It's a fast setting 100% solids polyurea. You fill the joints with clean silica sand and then saturate them with the polyurea. You can grind 20 minutes later. We have a review of the product here.