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Sashco’s Slab vs. Mor-Flexx: Which is the Best Concrete and stucco Repair Caulk?


It can be confusing to choose the right caulking product when they have a lot in common.

Say you have a concrete crack in your sidewalk, and a crack in your stucco near a window. Sashco makes two great products, both made for these textured surfaces. So which one should you use?

The answer is both.

Yes, Sashco’s Slab® and Mor-Flexx® have some similarities:

How Slab and Mor-Flexx are different

Packaging (Yep, they look different.)
UsesCracks in horizontal concrete, like sidewalks, driveways, garages, basements, and more.
Slab - Where to Use Sidewalk
Cracks in vertical surfaces, like stucco, and the mortar in between brick and stone



TextureLightly textured to match the texture of concreteMore heavily textured to blend in with mortar and stucco
Color1 color: Gray, to match aged concrete
Slab Color Chart
2 colors: Gray and Beige, to match the most common mortar and stucco colors
FormulaSpecially formulated:


  • For superb adhesion to concrete
  • With extra elasticity, to handle the extreme movement and heaving that concrete undergoes with changes in temperatures and humidity
Specially formulated:


  • For superb adhesion to brick, stucco, stone, mortar, and other common building materials
  • With extra elasticity, to handle the movement that all normal homes undergo with wind and changes in weather

Can I use Slab in place of Mor-Flexx? Or Mor-Flexx in place of Slab®?

You can use Slab wherever Mor-Flexx is used, but it may not match as well. For better overall aesthetics, opt for Mor-Flexx.

In response to the second question, no. Mor-Flexx is not designed to hold up to foot and vehicle traffic.

The right product every time!

Sashco makes it easy for you to choose the right product for each project around the house. Click here to find your project and the Sashco products that are perfect for you.

See also:

VIDEO: Introducing Slab®: The Serious Fix for Concrete Cracks

VIDEO: How to Fix Cracked Mortar Around a Fireplace

How To Fix Concrete Cracks

How To Repair Cracks in Brick, Stucco, and Mortar

Concrete Crack Repair in 5 Easy Steps

Top 3 Reasons to Use Slab®